Grading landscapingSMART. 3D-Machine Control Systems. Stormwater Management [2nd ed.] 3038215082, 9783038215080

Citation preview

Grading

landscapingSMART 3D Machine Control Systems Stormwater Management

Grading landscapingSMART 3D Machine Control Systems Stormwater Management Peter Petschek With a foreword by Peter Walker 2nd edition, revised and expanded

Edited by the HSR – University of Applied Sciences Rapperswil Landscape Architecture Degree Program Birkhäuser Basel

The photos at the beginning of each chapter are from the series “caminos,” by André Lehner, photographer, Zurich. The streetscapes are from Switzerland, South America, and Cape Verde. Editing and project management: Véronique Hilfiker Durand, Basel Layout, cover design, and typesetting: Manuel Aurelio Ramírez Pérez, Campanillas / Málaga Cover picture: André Lehner, Zurich Typeset correction: Véronique Hilfiker Durand, Manuel Aurelio Ramírez Pérez Translation from German into English: Laura Bruce, Berlin Copy-Editing: Susan James, Etobicoke, ON Proof-Reading: Sabine Rochlitz, Riehen

A CIP catalog record for this book is available from the Library of Congress, Washington D.C., USA. Bibliographic information published by the German National Library The German National Library lists this publication in the Deutsche Nationalbibliografie; detailed bibliographic data are available on the Internet at http://dnb.d-nb.de. This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, re-use of illustrations, recitation, broadcasting, reproduction on microfilms or in other ways, and storage in databases. For any kind of use, permission of the copyright owner must be obtained. The first edition entitled Grading for Landscape Architects and Architects was published in 2008 (ISBN 978-3-7643-8502-6). This book is also available as an enhanced e-book (e-Pub 3.0) (ISBN 978-3-03821-666-7). This book is also available in a German language edition Geländemodellierung. landscapingSMART, 3D-Maschinensteuerung, Regenwassermanagement (ISBN 978-3-03821-509-7). © 2014 Birkhäuser Verlag GmbH, Basel P.O. Box 44, 4009 Basel, Switzerland Part of De Gruyter Printed on acid-free paper produced from chlorine-free pulp. TCF ∞ Printed in Germany ISBN 978-3-03821-508-0

9 8 7 6 5 4 3 2 1

www.birkhauser.com

The author would like to thank the following people and institutions for their financial and expert support

Sponsorship: HSR – University of Applied Sciences Rapperswil Landscape Architecture Degree Program ILF Institute for Landscape and Open Space Grün Stadt Zürich A. Tschümperlin AG Visit the video lecture series of the HSR Landscape Architecture Degree Program.

REHAU

Expertise: Prof. Sadik Artunc Prof. Hannes Böhi Michael Fluss Peter Geitz Ulrike Nohlen Thomas Putscher Marco Riva Toni Sacchetti Christian Tack

Project management, editing: Véronique Hilfiker Durand

Contents

8

Foreword by Peter Walker

12

Introduction

18

History of Site Grading

19

Developments in Plan Representation

25

Selected Projects

26 29 35 39 45 50

The Pueblo Grande Ball Court The Pyramids of the Branitz Landscape Park The “Poet’s Garden” at the G 59 in Zurich The Olympiapark in Munich Irchel Park Zurich Landform at the Scottish National Gallery of Modern Art in Edinburgh

58

Landform

68

The Basics of Site Grading

69

Small and Large Scale

71

Slope

71 72 72 73

Slope Calculations in Percent Ratio Angle of Incline Gradient Formations

75

Interpolation

77

Spot Elevations

78

Contour Lines

84

Embankments

85

Profile

87

Cut and Fill Calculations

87 88 88

Volume Calculations Using Profiles Volume Calculations Using Contour Lines Calculating Volume with Triangular Prisms

90

Grading: Purpose and Techniques

90 94 95 95 96

The Purpose of Site Grading Important Criteria Minimum and Maximum Slopes Site Grading and Architecture Approach to a Grading Plan

102

Grading and Layout Plan

108 109 112 114 115 116 117 118 120 122 124

Landscape Stabilization Soil Erosion and Landslides Embankment Angle and Construction Technology An Overview of Slope Stabilization Construction Techniques Bioengineering Construction Methods Soil Protection Techniques Ground Stabilization Techniques

Stabilization Using Lime and Cement Reinforced Earth Geotextiles Retaining Walls

125 125 Cantilevered Retaining Walls 125 Gravity Retaining Walls 128 Gabions 130 Stone Block Walls 130 Pre-cast Element Retaining Walls 130 Natural Stone Retaining Walls 132 133 133

Grading Roads and Parking Spaces Grading and Roads Technical Basics

139 Grading and Parking Spaces 139 Terms 140 Arrangement and Dimensions 140 Horizontal Layout 141 Vertical Layout 142 Borders 142 Planting 143 Handicapped Parking 143 Parking Lots in Overview: Tables, Calculation

Basics, Layout

152 153 160 160 161

Grading and Stormwater Management Stormwater Management Basics Workflow and Calculations for Stormwater Man-

agement

1. Optimization 2. Water infiltration is not possible in the following cases

162 163 168 170 177 178

3. Calculating Stormwater Runoff 4. Sizing Debris Traps, Box Gutters, Manholes, and Pipelines 5. Infiltration Test to Determine the Specific Infiltration Rate (IRspec) 6. Sizing the Infiltration System 7. Calculating the Required Capacity

landscapingSMART and Digital Terrain Modeling

181

Data Bases and Data Collection

184

Small-Scale Data Collection and Staking Out Work

186

Wooden Pegs and Batten Profiles

188

Digital Terrain Models

193

Cloud Services

195

Analog models

195 History 195 Sand Models 197 Digital Models 197 Real-time Models 200

Grading and 3D Machine Control Systems

201

GNSS and DGPS

203

How 3D Machine Control Works

208

DTM Processing for 3D Machine Control Systems

209

The Requirements a DTM Must Fulfill to Be Applied by the Construction Company

209 Site Surveys / Basic Data 209 Interchange Format 209 Alignment 209 DTM “Surface Covering” 209 DTM “Subgrade” 210 Curbs 210 Road Construction Projects 210 Engineering Structures 211 Excavation Work 211 Lines and Pipes

212 215 219 221 222 224 226 230 232 236 240 242 244 246 248 250

252 253 275 281 284 285

Terrain Modeling and Construction Machinery Machinery for Soil Ecavation and Loading Machinery for Soil Transportation Machinery for Soil Compaction Construction Machines for “Rainbowing”

Grading in Practice Ertingen-Binzwangen Flatbed Glide, Geitz und Partner GbR Landschaftsarchitekten Erlentor Stadthof, Basel, Westpol Landschaftsarchitektur Swiss Cottage Open Space, London, Gustafson Porter Northumberlandia, Cramlington, Charles Jencks and the Banks Group SGI/Google Corporate Headquarters, Mountain View, SWA Desert Ridge Marriot, Phoenix, SWA 2500 Hollywood Way, Burbank, SWA Qiaoyuan Wetland Park, Tianjin, Turenscape Landscape Architects Victorian Desalination Project, Victoria, ASPECT Studios Millenium Parklands, Sydney, PWP Landscape Architecture

Appendix Exercises in Grading Glossary Literature / Sources Illustrations Biographies

Foreword by Peter Walker

It is with great pleasure that I write this introduction to Grading. landscapingSMART, 3D Machine Control Systems, Stormwater Management. Certainly, the importance of earth grading to our profession cannot be overestimated. In my first public project as a young landscape architect in 1960, the grading established the site plan but also determined the human scale of the car-free campus. Foothill College in Los Altos Hills, California, near Palo Alto and Stanford University, was one of the first post-war, two-year junior colleges to be built according to an ambitious Californian master plan to expand all higher-education facilities in the state. The site consisted of two rather steep small hills with a series of mature oaks and redwoods that we intended to preserve. The proposed complex of buildings, however, was too large to fit comfortably on either hilltop, and so it was decided to divide the spatial plan with the academic complex on the northern hill, and the sports facilities to the south. The two hills were joined by a wooden footbridge. Since there was still not enough level terrain for the plan, we decided to grade down both hilltops. Our goals were accomplished with a balanced grading plan that aesthetically shaped the site into a beautiful and prizewinning campus of rolling lawns and winding paths, without the loss of any of the major existing trees. For thousands of years, earth-moving work was done manually. Buildings and roads, farms and fields were generally adapted to the existing contours of the site, which remained largely unmodified. Moving earth was so expensive that only kings and emperors could afford major projects, such as the famous Imperial Gardens outside Beijing. Then, early in the twentieth century, motorized draglines, bulldozers, and trucks began to bring down the price of grading, beginning with major public works projects and strip mines. After World War II, the increased size of the mechanical equipment further reduced the costs and time required for extensive grading. In the late 1940s, earth grading was greatly expanded to include the building of roads, urban and suburban building complexes, and the post-war housing explosion. It became less expensive to modify the shape of the land than to fit the building’s foundations to the natural morphology of the site. Mass grading revised the age-old techniques for dealing with foundation construction, compaction, drainage, and water retention. These new techniques were primarily the domain of engineers and builders. Only a small group of landscape architects and landscape designers recognized the aesthetic potential for shaping the land. Engineering, mapping, and design techniques were generally limited to abstract geometric forms

Foreword

9

Peter Walker, November 17, 2005 during his lecture to the Landscape Architecture Degree Program at the University of Applied Sciences Rapperswil.

and straight, linear transitions. Design was limited to the balance of cut and fill. Often the visualization of the graded form was restricted to a series of cross sections that only depicted cut and fill. Soil analysis was generally limited to gauging porosity and compaction potentials. Occasionally, organic topsoil was stripped off the graded site (to be replaced later), but usually this was done to remove soil that was difficult or impossible to compact to levels that would support foundations or building slabs. Landscape architects from the late eighteenth century onward have worked with a system of contours displayed on a plan that enabled trained eyes to visualize the shaping of the land, not only to accommodate land uses, but to produce three-dimensional forms of aesthetic importance. Landscape architects made models to visualize the three-dimensional results. In the 1970s, the public became aware of environmental concerns, such as water use and retention, and the protection of wetlands and aquifers. At first, issues surrounding erosion and habitat triggered a negative public reaction to all grading. Then, over the next generation, as scientific knowledge increased in soil science, hydrology, erosion control, planting strategies, and rebuilding of habitat, it became possible for landscape architects to design grading and planting concepts both on the regional scale and for specific sites. This has opened up a great new opportunity for shaping an environment that is conducive to human requirements—and also for repairing the damage that resulted from the unsophisticated earth grading and strip mining that was prevalent through most of the twentieth century. The last fifty years have seen a massive increase in the space allocated to automobile parking. If roads are included, this driving-parking combination comprises almost half of all “designed” land uses. Parking largely requires flat surfaces, and, hence, dominates grading and drainage practice. Considering the modern demands of sustainable water us-

10

Grading and vegetation.

age, a careful consideration of surface parking is of prime importance. It therefore seems useful to consider these two areas of design together. In the post–World War II explosion of development in the United States, earth moving played a major positive, as well as negative, role in the creation of the modern environment. At worst, millions of trees have been removed, countless millions of cubic meters of topsoil have been lost forever, and in many places the recharging of drainage and groundwater has been ignored, often resulting in landslides and flooding. At best however, these design techniques have produced elegant parks and recreation areas, and reclaimed brown fields and strip mines. The difference between the two outcomes lies in the knowledge, vision, and skill of those designing our environment. Grading is an important tool for broadening knowledge, and hence increasing the opportunities for site designers, engineers, and landscape architects throughout the world.

Spring 2014

Foreword

11

Introduction

Grading plays a key role in landscape architecture. Although the professional spectrum is very broad and grading is not necessarily part of every project, each intervention designed by a landscape architect involves some modification of the earth’s surface. As a basic principle, design and ecology interact with technology and economy to lay the foundation for good landscape architecture. This tenet also applies to grading. Along with vegetation, grading counts as one of the most important design tools of landscape architects. Organizational principles of architecture such as hierarchy, symmetry and asymmetry, or rhythm and repetition can be used in grading. An artificially created hill in the English Garden in Munich holds a powerful appeal for park visitors: the strolling pedestrian wants to know what can be seen from the top of the hill. The terraces of the Italian Renaissance gardens—defined through levels, embankments and walls—create formal, clearly laid out spaces, which usually incorporate the views of the surrounding landscapes as an integral part of the design. In contrast, the poetic miniature landscape of the Katsura Rikyu Gardens in Kyoto surprises visitors with its ever-changing views of the lake and buildings on the site: a few steps taken in the garden and the view is suddenly broken by a swell in the ground, and replaced by a new scene. Circulation routes are the ideal means of implementing spatial dramaturgy through grading. The English landscape gardeners of the eighteenth century were masters of manipulating terrain for dramatic circulation. When a path disrupted the view into the distance, it was made to disappear by being sunk out of view. Grazing animals were kept away from paths and lawns through ha-has. These trenches, dug with the most basic tools, enabled views without the presence of obtrusive fencing in the landscape, while retaining the cows and sheep as decoration.

Introduction

13

The Monopterus is a wellknown viewing hill and attraction in the English Garden in Munich. Friedrich Ludwig von Sckell, the founder of landscape gardening in Germany, designed the park at the beginning of the nineteenth century.

Soil is an elementary material in nature’s household and the chief building material used in grading. On construction sites, soil is sometimes handled carelessly. This is in part due to the frequent showers and long cold periods of continental Europe, as well as the ubiquitous muck of a construction site. On the other hand, when it is explained in a warm, dry lecture hall that we are dealing with a material of life-giving importance, practitioners willingly agree. Weathered rock material, mixed with dead and metabolized organic substances, together with air and water, form the product soil. It takes around a thousand years for a few centimeters of topsoil to accumulate. Soil cannot be manufactured and therefore should not be wasted. Today, in most countries, building standards and guidelines regulate soil conservation on construction sites. In addition to light and water, soil is a prerequisite for plant life. The significant role of vegetation in ecological systems should be well known to readers. Here are just a few key points: — Plants produce oxygen — Plants serve as a food source — Plants protect the soil — Plants affect local climate conditions In the context of grading and terrain modeling, it should be pointed out that with sensitive grading, woods, trees, and protected vegetation areas can be conserved. As such, grading is an important instrument for ecologically oriented designers.

14

Katsura Rikyu in Kyoto was built between 1620 and 1645. It is one of the first accessible gardens of the Edo period and a classic of Japanese garden art.

Repetitions in the form of earthworks. Marina Linear Park in San Diego, USA, by Martha Schwartz Partners.

A ha-ha in front of Heaton Hall in Heaton Park, Manchester. The grading provides a view into the distance.

Introduction

15

A soil section provides information on important soil parameters.

“Keep water away from the building” is an old and well-known builder’s rule of thumb. It can only be achieved with well-functioning grading. In antiquity, the Romans constructed roads atop earth-filled dams that were built up to a meter above the surrounding terrain. The road surface was then laid on top of these dams. This might be the origin of the word “highway.” Technical competence in surfacing, surface grading, geotechnology, and horizontal and vertical road alignment, as well as rainwater management are the basis of good grading. During grading design, economic considerations unfortunately often cause adverse changes to the local landscape character. For instance, in gardens where the client wishes to have a level area running up to the property line, unattractive prefabricated concrete elements are often used to hold back steep slopes. These ugly retaining walls, commonly found in new housing developments, contribute to the interchangeability of places. Roads that cut through hills and mountains to allow faster travel have small-scale yet cumulative harmful effects on the character of the landscape. A committed and responsible landscape architecture should pursue meaningful variation, carefully considering design, ecology, technology, and economy. Proficiency in grading is indispensible.

16

Site grading can only be learned through extensive practice.

“The contour line is the single exact possible representation for the free, natural shaping of a site in plan; so, become proficient with this instrument!” (Loidl, 1990, p.  34). Hans Loidl, landscape architect and professor, formulated this statement in his treatise on landscape design. His declaration is correct, but where and how can one best gain these skills? In America, grading is found in the core curriculum of every accredited university. Students at the bachelor level in European postsecondary institutions most often study grading as part of surveying classes. The importance of technical surveying knowledge and site mapping is indisputable. This forms the essential base for all site grading, particularly since the advent of digital terrain modeling and easy-to-use tacheometers with interfaces to CAD programs. Nevertheless, the strengths of the landscape architect remain in site design. Landscape architects must be in a position to design using contour lines, to quickly develop alternatives, and to evaluate variations based on design, ecology, technology, and economy. This can only be learned through intensive work with contours in an independent course on grading.

Introduction

17

History of Site Grading

Developments in Plan Representation The development of grading plans is closely linked with that of cartography, as the transfer of landforms to maps is the most important field of activity for cartographers. In particular, sea-faring maps were of strategic importance in the past, and were drawn and updated with the utmost secrecy. In the era of Google Earth maps and mobile GPS equipment, it is difficult to imagine what life was like without geo-information. To begin with, relief was presented in profile. The famous Swiss cartographer Eduard Imhof (1895–1986) described the typical early mountain symbol as a molehill (Imhof 1965). This landform representation style was followed for many centuries. During this period, maps resembled two-dimensional pictures that showed cities, castles, monasteries, forests, and mountains. The Renaissance discovery of perspective led to a more realistic portrayal of landforms. The maps of Tuscany that Leonardo da Vinci drew between 1502 and 1503 are good examples of this new technique. Individual hills and towers that are typical of the region, and home to the often rival families, are clearly identifiable. These folios are early evidence of the use of perspective in landscape representation. The transfer of isometric delineation to maps began in the seventeenth century. The military required better mapping to be able to use new weapons technology. Cavalier, or military, perspective definitively replaced the profile view. A “cavalier” is a high parapet of a fortress. From here, the surrounding landscape is visible in half-perspective. Among the best-known illustrations of the age are the town images by Matthäus Merian (1593– 1650). The lighting in his etchings always comes diagonally from the left. The resulting play of light and shadow creates a very spatial impression. By the end of the eighteenth century, the bird’s-eye view had replaced the cavalier perspective. The observer’s viewpoint had shifted upwards. In the nineteenth century, map representation developed in the form of the plan view. Cross-hatchings and other shading methods were introduced to emphasize topography, which made reading and understanding the map considerably easier. Slope hatchings are always in the direction of the drawn line of the steepest decline. Where there are dramatic relief forms, the cartographers use shadow shading. The Dufour map (1844–1864), drawn by the French federal chief of staff General Guillaume-Henri Dufour at a scale of 1:100,000, is a fine example of such plastic landform representation. Today, shading is used in combination with contour lines to portray landforms on topographical maps. In most maps, the lighting is from the northwest, so that the relief form stands out best.

History

19

Konrad Türst’s Map of the Federation from 1495/97. This is the oldest map of Switzerland. Even Türst used the molehill technique to represent mountains.

Leonardo da Vinci: Codex Madrid. Several folios of Volumes I and II, which were lost until 1965, are land maps of Tuscany.

A cavalier perspective of Zurich by Matthäus Merian, Topographia Helvetiae, Rhaetiae et Valesiae, 1654.

Right: Dufour map (1844–1864), Matterhorn detail.

In parallel with the very effective relief representation techniques, the contour line started to gain importance in the nineteenth century as a way to represent elevation information. Determining spot elevations and laying out the resulting contour lines was made possible by the introduction of an international metric system and an ascertained null datum. Contour lines are lines that connect points of the same height above a reference surface (sea level). Their function is to map the relief (or topography) of a landscape. The advantage of contour lines is that they deal in quantitative information about the terrain. Other terms for contour lines are isopleth, isoline, isogram, isarithm, and isohypse. Lines beneath a zero horizon are known as depth contours or isobaths.

20

History

21

The highest point in Switzerland (4634 m above sea level) was named the Dufourspitze in honor of the cartographer General Guillaume-Henri Dufour. The summit is the small, dark rockface in the middle.

The earliest application of contour lines is attributed to the Dutch surveyor Nicolaas Cruquius. In 1730 he drew a map of the river Merwede. Using depth soundings, Cruquius measured the depth of the waters and documented his results in the form of contour lines. Today, contour lines are not found only in marine charts, but are used in a wide range of maps, including recreational maps. Contour lines are considered to be the cartographical representation of topography. As they communicate a graphical impression of the shape, slope, and elevation of the terrain, landscape architects use them to show intended earthworks. The evolution of computer technology has led to the development of new working methods and presentation techniques in mapping and planning. The first research into digital-level mapping was carried out in the late 1950s by C.L. Miller and R.A. Laflamme in the Photogrammetry Laboratory of the Civil Engineering Department of the Massachusetts Institute of Technology (M.I.T.) (Miller, Laflamme 1958). In the 1960s and 1970s expensive mainframe computers—VAX, McDonnell Douglas, and Intergraph computers—were required to compute terrain models. Only universities and large firms were able to afford this technology.

22

The western page of “De Boven-Merwede” by Nicolaas Cruquius, 1730.

The eastern page of “De Boven-Merwede.” These etchings are two of the earliest contour maps.

History

23

Coordinate map 1:25,000 (original scale) from the LK25 map sheet 1111 Albis, Swisstopo.

Contour line plan (hand drawing) by the golf course designer Peter Harradine.

The commercial introduction of personal computers at the beginning of the 1980s gave rise to the IT revolution, and meant that medium-sized and small businesses could acquire computer technology. One of the first PC programs developed for technical drawing was AutoCAD (Version 1.0–1982). In the mid-1980s, the mathematician and software writer Kevin Lynch developed the program AutoMap, based on AutoCAD. This program was able to automatically interpolate polylines from x, y, and z co-ordinates and was probably the first PC terrain modeling software. In 1986, this program caught the interest of David Arnold, David Paine, and Terry Bennet of the small engineering consultancy DCA, established in 1985. They wanted to open up a new niche, and started with two IBM PCs, a Calcomp 1098 printer, and two copies of AutoCAD Version 1.5. As the CAD program was not set up for the construction industry, DCA developed survey procedures and a symbol library, which they were quickly able to sell to other local firms. Along with a version of AutoMap released by Lynch, they brought DCA Engineering Software onto the market in 1987. In 1989, DCA Engineering Software purchased the licensing rights to AutoMap, and was known during the 1990s as a software producer in the road and civil engineering industry under the name Softdesk. In 1997 the company was bought out by Autodesk, and together they developed what is now the most popular civil engineering and terrain modeling program in the world, Civil 3D.

24

CAD workstation in a landscape architecture office in 1988 with a PC (16 MHz, 8 MB RAM, MS-DOS operating system, AutoCAD Version 9), digitizer tablet, and pen plotter.

DCA site model by the author for a golf course, 1991.

Selected Projects If topography is to be factored in as a design element, it is worth taking a short look back into history. This short selection is by no means exhaustive. The selection criteria were the particular landform and the availability of construction information. Shaping topography is of course much older than landscape architecture. Round or oval areas, often terraced into the site, were used in ancient times as performance sites for competitions and theater. However, it was not just the Greeks and Romans who used earthworks to build recreational facilities.

History

25

Adobe settlement in the American Southwest.

The Pueblo Grande Ball Court The Hohokam were Native American Indians who cultivated corn, beans, tobacco, and cotton up to the sixteenth century in what is now Arizona and northern Mexico. Pueblo Grande is an archeological excavation of this culture, which lies on the outskirts of Phoenix, Arizona. Along with the affiliated museum, the archeological park documents the life of this now-extinct tribe. From the perspective of grading, the “football pitch” or “arena” areas in Pueblo Grande are very interesting. According to museum documentation, there are several of these spaces in each Hohokam settlement. Grounds or courts for ball games are found in other excavation sites in Central and North America; however, in these other cases landform is of no importance. The Hohokam “arena” is an oval about 25 to 35 meters long, about 15 meters wide, and slightly sunk into the ground. The excavated soil is banked into earthen walls up to three meters high that surround the arena. As in modern sports arenas, these served as seating for spectators. The large Hohokam arena just outside of Phoenix has earthen walls with a spectator capacity of around 500 people. The playing surface of the arena has been made smooth by means of a lime stabilizer and formed like a tub. At each end of the grounds, a small opening formed a goal. As in soccer, the players tried to get the ball into their opponents’ goal. Stone markers in the ground in front of the goals and in the middle of the pitch indicate the play areas. Unfortunately, nothing more remains of the game, as the Hohokam Indians no longer played it by the time the Spanish arrived in Arizona in the mid-sixteenth century (Andrews, Bostwick 2000, p. 26). Anyone who lands at Phoenix airport and is interested in topography should certainly visit the nearby Pueblo Grande!

26

A bare earth playing field for Hohokam Indian ball games.

The stone in the middle is a play area marker; in the background is the goal.

The surface is drawn up the sides like a tub and is smooth.

History

27

Isometric view of the shaded triangulation.

Plan (triangulation) of the Pueblo Grande Ball Court. The internal area is 30 meters long and 25 meters wide.

28

The steps up the land pyramid.

View from the land pyramid to the lake pyramid.

The Pyramids of the Branitz Landscape Park Hermann Fürst von Pückler-Muskau (1785–1871) was a landscape gardener, well-traveled writer, eccentric bon vivant and gourmet. “Very regularly the 24 hours of my day are divided into four parts: one quarter is devoted to parks, another to writing and reading, and the remaining two to sleeping and eating.” (Lauer, 1996, p. 28). A great enthusiast for the English landscape garden, Pückler-Muskau built two significant parks in Germany in the nineteenth century. His main work was the garden at the family seat in Muskau. In the book Andeutungen über Landschaftsgärtnerei (Suggestions on Landscape Gardening) he expounds on his design principles. Because his expensive lifestyle landed him deep in debt, and despite his tirelessness in perfecting the garden, Pückler eventually had to relinquish the residence in Muskau. In 1845 he moved to an estate he had inherited in Branitz near Cottbus, about 12 kilometers from Muskau. There, even though constantly plagued by money troubles, he built his second great garden masterpiece. From 1846 until his death he designed the landscape park in various phases. Topography played a dominant role in this garden. The Branitz Landscape Park features two earthen pyramids: a lake pyramid and a land pyramid. The lake pyramid, built between 1856 and 1857, was intended to serve as his own sepulcher. “So the path to the tumulus is opened to me,” were Pückler’s last words (Lauer, 1996, p. 9). The land pyramid, intended for his wife, was completed in 1863. On the tops of the pyramids Pückler had inscribed: “Tombs are the summits of a distant new world.”

History

29

Original pencil drawing from 1866/1867 of Branitz Landscape Park, showing both pyramids (section).

Pückler’s pyramids relate in function and proportion to the ancient Egyptian burial tombs. The pyramids at Giza were perhaps the archetype for the water pyramid. These could be reached by boat when the Nile was in flood. For the land pyramid, Pückler borrowed from the Egyptian pyramid at Meidum, which rises out of a mountain of rubble (Tietze, 1999, p. 36). Pückler himself had climbed to the top of the Great Pyramid of Cheops during his trip to Egypt. “But so as to endow here a rarity, which is hardly to be found in the rest of Europe, I arrived at the idea of erecting an ancient tumulus as my tomb, a four-sided pyramid made of earth.” (Lauer, 1996, p. 9). Pückler spent 1854 occupying himself with the design of the pyramids. “There is not too much to say about this. The most important thing may be that one must spare them as much as possible. The natural unevennesses of the site are generally more picturesque than that which Art can achieve with much effort. Artificial hills normally have but little effect. However, they may be necessary to obtain a view from the top, to give planting more height or to dispose of the earth spoils from a dug lake.” (Pückler-Muskau, 1988, p. 137). The steepness of the lake pyramid led to discussions with his head gardener. Pückler wanted a slope of 45° (1:1). In the end, the works contract fixed a height of 12.80 meters and a base width of 32 meters, resulting in a slope of 39° (1:1.25). For comparison: in road construction today, embankments with a slope of 33.7° (1:1.5) are typical. In addition, the contract contained information about the technical construction of the

30

In all likelihood, the inmates of the Cottbus penitentiary used “pushcarts” like these to build the pyramids (Henz 1856, plate IV).

On very steep sites horse power assisted the pushcarts (Henz 1856, plate IV detail).

pyramid: “Soil compaction should be performed with a piling hammer every four feet, and sandy soil should be laid only in the interior of the pyramid. The exterior should be clad with a 3-foot-strong layer of heavy earth.” (Neumann, 1999, p. 10). The construction of the pyramid was projected to take six months. To keep the cost down, the earthworks were built using the labor of inmates from the Cottbus penitentiary, using wheelbarrows. “For the laborious earthworks in the park, as a rule about 50 to 60 prisoners were used, and at times up to 120.” (Schäfer, 1999, p. 137). Being a landscape gardener and gourmet, Pückler was not one to neglect his own physical well-being: “I spend several hours daily at the pyramid with a jug of beer beside me, as we have very thirsty weather . . . you know how much I love that.” (Kohlschmidt, 1999, p. 194).

History

31

The Princely Park, Branitz Landscape Park Plan from 1903, a donation by the Vereinigung ehemaliger Schüler der Potsdamer Königlichen Gärtneranstalt (Association of Former Students of the Potsdam Royal Gardening School).

The Branitz pyramids are just one example of the numerous earthworks projects of that era. A description of site grading in English landscape parks alone would fill volumes. Nevertheless, Pückler’s eccentric earthworks remain unique. To have built burial pyramids for oneself and one’s wife in an age without bulldozers and diggers, while at the same time accumulating a mountain of debt, is a highly peculiar endeavour.

Top right: The tumulus, tableau of the stately home Branitz and its surroundings, 1857. Steel engraving by Poppel and Kurz after a drawing by Gottheil. Bottom right: Tableau of the stately home Branitz and its surroundings, 1863. Steel engraving by Poppel and Kurz after a drawing by Gottheil.

32

History

33

The lake pyramid in the foreground, the land pyramid in the distance.

View of the lake pyramid from the park.

“Tombs are the summits of a distant new world,” reads the engraving on the railing of the land pyramid.

34

The grass pyramids in the “Poet’s Garden” were very popular with children. However, many adult visitors did not understand the abstract garden space.

The “Poet’s Garden” at the G 59 in Zurich Two-thirds of Switzerland is covered by mountains. On a clear day, the Alpine panorama is breathtaking. Grading is a particular challenge in Switzerland, as there are usually impressive, natural examples right in front of one’s nose—except when it is foggy. Ernst Cramer (1898–1985), one of the most important Swiss landscape architects of the twentieth century, was asked to design a “Poet’s Garden” for the first Swiss Garden Expo, G 59. It was not an easy undertaking to create a contemplative space in the middle of a colorful sea of flowers; indeed, the G 59 was aptly titled “Flowerland.” The temporary exposition was located on the eastern shore of Lake Zurich, known today as the Blatterwiese. The 2500-square-meter installation was composed of four grass pyramids, a grass cone, and a flat water basin that reflected those shapes. The pyramids were 2, 2.8, 3, and 4 meters high. The asymmetrically stepped cone was 3 meters high and 11 meters in diameter. Interestingly, many visitors estimated the pyramids to be twice their actual height. The perspective effect of the sloped sides certainly contributed to this impression (see Weilacher, 2001, p. 108). “The garden was not so much a garden as a sculpture to walk through, abstract earth shapes independent of place, with sharp rises foreign to the nature of their material” (Kassler, 1964, p. 56). The project, with the abstract grass pyramids reflected in the water’s surface, was included in a 1964 publication by the Museum of Modern Art in New York, titled Modern Gardens and the Landscape, next to work from Burle Marx and other high-profile landscape architects, architects and artists, and thus achieved world renown. As no construction documents are extant, and according to Fritz Dové, a landscape architect who was employed by Cramer for many years, no construction documents were drawn, technical construction details can only be deduced from photographs. Fritz Dové wrote: “The published drawings probably also served as construction drawings. By entering the height of the tops of the pyramids they were useable for the rough grading

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The “Poet’s Garden” shortly before completion.

work, and the final form was influenced by the quantity of available material and the sinking of the fill area,” (Fritz Dové, email on August 9, 2007). Dové goes on to explain that in any case, Ernst Cramer felt more at home on site than at the drawing table and often made important design decisions in situ. The garden was built by Cramer’s own landscape construction firm. Children frolicking on the earth shapes quickly caused erosion and loss of the precise geometry (see Weilacher, 2001, p. 115). To prevent damage from the wear-and-tear of people walking, and to ensure the development of a stable sod, the grass should not have been accessible during the first season. But because it was a temporary garden and had to be built in the shortest possible time, this was not possible. Despite these structural shortcomings, it should be stated that in his projects Cramer put much emphasis on professional site earthworks. In an interview between the landscape architect Stefan Rotzler and H. J. Barth, a landscape architect who worked for Cramer for five years, Barth made the following remark: “Plants and earth levels were not some dull task as in other offices, but rather there was a special doctrine of harmonics. For example, an embankment had to become increasingly flat towards the bottom, to produce a very flat embankment base, and the top edge was quite strongly emphasized. This was a very specific motif which E. Cramer paid meticulous attention to.” (audiotape transcription, anthos 2/87, p. 5). Unfortunately, in the fall of 1959, at the end of the Garden Expo, Ernst Cramer’s trail-blazing earthworks were completely leveled.

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Sides up to 45° steep made the work on the earth pyramids difficult.

The slope’s top edges were not further stabilized.

Cramer placed great value on precise site modeling in his construction company.

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Design drawing of the “Poet’s Garden” by Ernst Cramer, Zurich.

Reflection of the earthworks in the garden’s water basin.

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The park’s viewing hill made from rubble from World War II and the excavation spoil from the Olympic facilities shaped the site.

The Olympiapark in Munich In addition to defining aesthetics and orientating site use, site grading can also be used to convey a political idea. The Olympiapark in Munich is a good example of this. “The goal of the 1972 Olympiapark in Munich is a contrast in spirit and architecture to the Olympic facilities built for the 1936 Games during Hitler’s era. The new facilities were to represent a different Germany, a tolerant, liberal country.” (Grzimek, 1973, p. 14). The motto of the first big international sporting event in post-war West Germany was “the Happy Games,” and for ten days even the whimsically shaped parking areas manifested this idea. Regrettably, a subsequent terrorist attack overshadowed the event. The Oberwiesenfeld site, situated to the north of Munich’s inner city, equals the inner city in area with its 280 hectares (2.5 x 1.5 kilometers). It had been used earlier as a parade ground and sports airfield, and during World War II was used as a dump for rubble from destroyed buildings. Apart from a single 60-meter-high mound of debris, the area was flat and bare. The construction of the sports facilities required a lot of excavation, so the flat site lent itself ideally to a new grading concept. The design and construction of the Olympiapark lasted from May 1968 to August 1972, and while the architects Behnisch & Partner were responsible for the overall master plan, responsibility for the design, construction documentation, and construction supervision of the landscape lay with Günther Grzimek (1915–1996). Frei Otto developed the roof construction in collaboration with Leonardt + Andrä. The interweaving of landscape and architecture is characteristic: sometimes the landscape seems to flow over the architecture, and at other times the landscape is totally penetrated by the architecture.

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The tent architecture was designed by the architects and engineers Behnisch & Partner, Frei Otto, Leonardt + Andrä; landscape architecture: Günther Grzimek.

Günther Grzimek has explained the “Olympic park idea” in various publications. Among other things, he emphasizes the esthetic of naturalness, describing the park as a “…place for daily use. Hill and lake, tree and grove, meadow and bog, shore and path, stone and gravel are the building blocks for a landscape that is natural and at the same time hard-wearing, as a good utility object should be.” (Grzimek, 1984, p. 71). He aspired to create a “user park” and a “utility landscape”; the park was to follow the people and not the other way round. It was to deliberately inspire people to freely and spontaneously use the lawns. A differentiated path system with main and secondary routes was developed to meet the requirements of both large-scale events and everyday leisure. A second important aim was the revitalization of a metaphor of educational freedom, which also defined the English landscape garden. Symmetry, hierarchy, and stone monumentality were avoided. Above all, as much as possible, nothing was to be forbidden: “The park allows its users largely free decision-making about their behavior.” (Grzimek, 1984, p. 70). Landform design is the main theme of the park. It is this that creates the connection between landscape and architecture, as a few quotes from Grzimek, who also taught as Professor of Landscape Architecture at the Munich University of Technology confirm: “The relief energy results from the relationship and composition of horizontal and vertical leading lines in the landscape. It increases with the diversity of the surface modeling, the richness of topographical elements, as there are flats, peaks, slopes and depressions, and so on.” (Grzimek, 1972, p. 11).

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Landform detail of the “utility landscape.”

The “taking” of the hill during the opening of the Olympiapark.

“The key concept developed for the Oberwiesenfeld was a continuous dialectic opposition and coexistence of significant topographic elements, whose formal polarity correlates with the contents of ‘privacy’ and ‘communication’.” (Grzimek, 1972, p. 12). “Apart from the elementary and inexpensive materials (gravel, stone, grass, trees, bushes), the program was an integral factor in the low construction costs. Large areas of the hill landscapes—the steep mountainsides—were created as wildflower meadows on poor soils. The ground was worked solely with machines. The gravel-rich soil proved highly robust for this purpose.” (Grzimek, 1984, p. 70). “[People do] not walk rigorously in a straight line, they wander—even without noticing it. They gladly oscillate in the third dimension—but with only 1 to 3° deviance from the flat. When they go up a mountain, it is either in a cut—or a long-drawn-out hill. One can anticipate the pathways. Nothing is by chance.” (Grzimek, 1993, p. 32). “On the grass, people walk differently than when on a designed path. There are no leading lines, so they move according to their feelings and the contours—when this is offered to them.” (Grzimek, 1993, p. 33).

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Different spaces are created using tree spacing and landform. Sketch by Carlo Weber.

The athletic stadiums were envisaged as earthworks with integrated spectator bleaches. Sketch by Carlo Weber.

Top left: Master plan of the Olympiapark by Behnisch & Partner, Stuttgart. Bottom left: Concept sketch at 1:2000 by Behnisch & Partner, Stuttgart. Sketch by Carlo Weber.

The park has a diverse, use- orientated circulation system ranging from informal trails to pedestrian lanes for large events. Sketch by Carlo Weber.

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View of the construction site from the lookout hill.

The view from the TV tower of the construction site from the upper end of the lake.

Landscape grading in progress in the fore- and middle ground, completed landform creation in the background.

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Panoramic hill, Irchel Park, Zurich.

Irchel Park Zurich Irchel Park, at thirty-two hectares, is one of the largest inner-city parks in Switzerland to be built within the last fifty years (construction duration 1980–1986). The basic concept was to contrast a raw, natural park —which was popular at the time— with the cubical architecture complex of the new university. The award-winning competition project by ASP Landschaftsarchitekten and architect E. Neuenschwander included a thirty-meter-wide “green bridge” that spanned the cut of the interrupting arterial road, so that both sections of the park could be connected and become a coherent park experience. The topographical relief is of particular interest. Four hundred thousand cubic meters of excess excavated soil were piled into belvederes and, on the lower perimeter of the area, into a chain of hills to serve as sound protection from street noise. This created a high level of contrast between convex and concave, between hills with a view above and hollow areas below. It also made it possible for all of the accumulated earth material, for environmental protection reasons, to be used on site. In the former agricultural area, all of the streams had been drained and covered over. These were re-naturalized and directed to flow around the buildings, and combined with the building’s drainage and roof water, into the lake and ponds of the area’s hollow areas. The tree-lined streams make the campus seem cloaked in green.

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Architectural grading near the new university buildings.

On the peripheries, the noise protection ramparts were forested, which intensified their effect and served to enclose the area. This produced a visual partitioning from the urban surrounding, and an Arcadian-like atmosphere for the park. Wet and dry areas, flower meadows, indigenous trees, the use of natural stone, wood, water-permeable ground surfaces and green roofs were part of the program, which more than satisfied the wishes of the natural sciences faculty. This “natural” design, however, was initially criticized by other professionals in the field as being arbitrary. Yet the design drive is very present in its implementation, moreover even geometric near the buildings, and hence, quite clear. An additional important aspect was the inclusion of outdoor artworks: ten striking works enrich the park experience. From the outset, the design considered the element of transformation for the entire site, which over the course of time is to develop a dynamic of its own. This transformation accounts for the successions of the plants and animals that inhabit the area, as well as the traces left behind by users. Irchel Park was welcomed from the very beginning by the population and has developed into an extraordinarily ecologically rich-in-species topos. It is a very popular and frequented place of rest and recreation in the city of Zurich, which reflects the important purpose of landscape architecture in the 1980s, and hence, is respected by other professions in the field here and abroad.

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Plan of the convex hill in levels, Irchel Park, Zurich.

Sketch of the overall situation: panoramic hill and new university buildings.

Detail sketch of the panoramic hill, Irchel Park, Zurich.

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Plan of Irchel Park, Zurich.

Concave terrain basin with staircase and lake.

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Grading near the new university buildings.

Grading detail: seating arrangements.

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The Scottish National Gallery of Modern Art, with the landform at the entrance, is situated on a hill named “The Mound” at the edge of the city center of Edinburgh.

Landform at the Scottish National Gallery of Modern Art in Edinburgh The architectural theorist Charles Jencks is considered the father of postmodern architecture. Several years ago, Jencks also began working on a practical level with landscape architecture. He combines two principles in his artistically shaped landscapes. The first originates from Chinese garden art and is the principle of “borrowed landscape,” meaning gardens as miniaturized landscapes. This principle is linked to the characteristic hill and lake landscapes of Scotland. The second principle is that of the wave. For Jencks, the wave is the basic pattern of all life and a metaphor for the entire universe. In an interview Jencks called his work “contour gardening,” referring to the hard edges of his graded earth embankments, which, particularly at dusk, distinctively trace the shape of the landform ( Jencks, 2005). A very impressive landform project designed by Jencks is found in front of the National Gallery of Modern Art in Edinburgh. The Scottish landscape architecture office Ian White Associates was responsible for the project management and construction supervision of the £350,000 project. The planning and construction each lasted one year; the project was completed in 2002. John Farquhar, the project landscape architect from Ian White Associates, wrote:

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Landform detail.

“As the completed landform was to be accessible to the public, safety and durability issues were critical to the construction process. A detailed site analysis was carried out followed by a rigorous construction methodology to determine the best approach to the works on site. A set of detailed drawings and specifications were prepared for tendering the project to an approved list of civil contractors. The landform covers approximately 3000 m2 (0.75 acres) consisting of 3500 m3 of fill material, stands 7 meters at its highest point and has three shallow serpentine pools holding 1,500,000 liters of water. A recirculation system linking all the pools provides a constant flow of clean water. The integrated irrigation system ensures the greening of the turf. The generous depth of topsoil across the front of the Gallery site was removed and stored for reuse as rootzone material. The lack of suitable site material to form the mounds necessitated the importing of inert oil shale as fill material. The material is an industrial waste product from the oils hale industry found locally to the west of Edinburgh. It has a very dense composition, generally ranges from 15 millimeters in diameter to dust in size, but due to its oily nature provided a cohesive quality for construction. The shale was placed and compacted in 300-millimeter-deep layers to the designed profiles. A series of cross sections were produced to highlight the varying gradients across the landform and a local grid was established to provide accurate setting out points for the serpentine ponds. The artist stipulated the steepness of the maximum 45¼ gradients on the landform. The benching of the layers was neatly finished along the edges by hand trimming to form a key for the rootzone material.

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Landform detail.

Right: Finished “Level and Grades Plan,” prepared by the landscape architecture office Ian White Associates. Page 54: Cross sections, Ian White Associates landscape architecture office. Page 55: Construction detail, prepared by the landscape architecture office Ian White Associates.

Everyone can access the landform, not only swans.

The approved profiles were then covered with a 200-millimeter-deep layer of manufactured rootzone material. This was composed of sixty percent site topsoil, thirty percent coarse sand and ten percent grit. To this mixture were added polypropylene mesh elements supplied by Advanced Turf, Netlon Ltd. at a rate of 3.50 kg/m3 to provide the necessary reinforcement for the rooting medium. The material was placed in one layer and accurately trimmed to design grades with a machine, however, care was required to avoid raking out the mesh elements. The finished landform was then inspected and approved before being covered with turf.

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History

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Landform under construction showing the formwork for the water edging.

The selected turf consisted predominantly of drought-resistant cultivars of fescues. Large rolls of turf were positioned on the top ridge and rolled out vertically down the face of the landform and pegged to secure at 600 millimeter centers with 150-millimeter-long biodegradable pegs. The joints were filled with a sand-soil mixture. Public access to the landform is limited to the opening hours of the Gallery; however, due to health and safety concerns, access is not permitted when the steep slopes are slippery and wet. The steepness of the turfed slopes necessitates the use of Flymo lawn mowing machinery on a rope and operated from the top ridge. An integrated irrigation system along the ridge of the landform ensures the greening of the turf. As an installation it does not have a predicted life, but there are renewable items such as pond liners and pumps that will have to be replaced in the future.” ( John Farquhar, Ian White Associates, email, September 4, 2007).

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Landform during the site grading.

Landform under construction showing the laying of the turf rolls.

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Landform

In geography, the term “landform” is used to describe the different formations of the earth’s surface. These can be divided into three main categories: convex, concave, and flat landforms. The inclines of convex forms descend downward from an apex, a flat area, or a lineal area, to the surrounding terrain. A hilltop is one example. The inclines of concave forms run down towards a surface, line, or point, as seen from the surrounding terrain. A depression is a typical concave form. Small leveling gradings can disrupt the inclines of both landform types. The term flat can be used to describe landforms with only minimal gradient. The three co-ordinates x, y, and z define the landforms described above. An appropriate graphic code is needed in order to represent three-dimensional information on a two-dimensional map. Isohypses (contour lines) are used on topographical maps for this purpose. The name originates from the Greek isos, meaning equal, and hypsos, meaning height. Contour lines run along the landform and refer to sea level. They are separated by a constant interval, called the “equidistance.” For unpracticed map-readers, contours are often only a distracting tangle of lines. However, once the observer has a bit of practice, contour lines open up a huge reservoir of information. By making a few successful contour line interpretations, the map’s landscape can be automatically visualized in the mind’s eye. The next step is to formulate the discovered shapes verbally so that information can be exchanged about them. Unfortunately, this is where we encounter our next problem. It is not only in daily language that terms for the diversity of existing landforms are used with great imprecision. One important reason why such a multitude of terms exists may be that up to now no general standard work has been established in the field of landform terminology. Georg Schulz has taken a step towards improving the situation with his book Lexikon zur Bestimmung der Geländeformen in Karten (Lexicon for Identifying Landforms in Maps). In contrast to other literature on map interpretation, the author limits himself to landforms, providing 300 definitions with detailed slope, height, and size indications. He also provides an interpretation key for correct landform terminology. A selection of landforms is presented on the following pages. These examples have been selected as they are both particularly common in continental Europe and didactically suitable for learning about contour interpretation. In each case, a contour map is compared with the corresponding three-dimensional terrain model. The brief explanations about the individual shapes and the digital models correlate with the principles clarified in Schulz’s Lexikon. There is not enough space here for an exhaustive exposition on the extensive field of landform. For this, we strongly recommend the above-mentioned work.

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Drumlin landscape near Menzingen in Canton Zug, Switzerland (convex).

Volcano in southern Italy (concave).

Spurs in a garden in the National Garden Festival (Bundesgartenschau) in Munich, 2005.

The Linth flats near Weesen, Switzerland (flat).

Depression shapes in a Japanese garden. Cone shapes in a hotel garden in Guatemala.

Constant slope With a constant slope the gradient is more or less the same over the entire area of inclination. In a topographical map, the constant slope is shown by consecutive parallel contour lines at an equal distance from one another.

Concave slope A slope is defined as concave when it possesses a curve negative to its mid-point. This basic form is shown in maps in the characteristic pattern of contour lines, which are initially far apart, but become closer with rising elevation.

Convex slope As the reverse shape of the concave slope, the curve of the convex slope is positive. On the map, this slope form is recognizable in the contour lines which are increasingly far apart with increasing height.

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Terrace A terrace is a flattening-out, which interrupts the uniform inclination of a slope. A terrace is composed of the terrace flat, the uphill slope lying above it, and the downhill slope below. When a slope is composed of many terraces on top of one another, it is described as terraced.

Pan A pan is an extremely flat, round depression, with slowly rising inclinations around the circumference. The extent of its surface is many times that of its difference in elevation.

Knoll In plan view, knolls are round; in profile they are a bell-shaped rise. The sides of a knoll are convex and radially abut the flattened summit area.

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Cone Cones are practically circular in plan, with the sides varying from elliptical to concave. They are centrally tapered and of various sizes.

Drumlin The term “drumlin” refers to an elongated elliptical hill with a width to length ratio of 1: 4. They are found in glacial landscapes, where the longitudinal axis lies in the direction of the glacial action. This landform resembles a droplet in shape.

Basin A basin is a roundish, concave landform with gently rising sides. These shallow and usually concave side slopes surround the flat basin floor on all sides.

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Cuesta The term “cuesta” refers to a steep escarpment formed through the erosion of different rock layers. A flat, gently sloped plateau, with a slope that corresponds to the underlying geological strata, is found at the top of the long extended escarpment.

Shoulder A shoulder is a long, high-altitude area that slopes down on two sides like a roof. But unlike the mountain ridge, the sides of a mountain shoulder are convex in shape when seen in cross section. Changes in elevation along the ridge line are significantly smaller than the changes in elevation of the side inclines.

Ridge Ridge defines an extended mountain edge where the two sides fall downwards from the ridge line like a roof. Changes in elevation along the ridge are less than in the cross section. If the ridge is already strongly eroded, convex, rounded dome forms are present. In contrast to a shoulder, the ridge cross section line is straight to gently concave as it tapers up to its crest.

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Summit ridge The summit ridge has a sharply formed ridge line with side inclines that fall away steeply, and are usually concave in cross section. Differences in elevation along the ridge are significantly less than those in the cross section.

Saddle The term “saddle” defines an indentation in a mountain ridge. In longitudinal section, a saddle appears as a basin-like depression.

Spur A spur is a long, narrow projection jutting out from a bigger, convex landform.

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Depression A depression is a broad, flat hollow that lies at the beginning of a valley. In cross section it is basin-like, whereas in plan it is not completely surrounded by rises. Unevenness on the depression floor is characteristic.

Basin valley A basin valley is shaped with a basin-like cross section, meaning the sides and valley floor are concave, whereas the sides may have a slightly convex top. The longitudinal section features a concave shape with an even slope.

V-shaped valley A V-shaped valley is a broad concave landform with V-shaped or rounded valley walls in cross section. The valley floor is largely the same as that of a water body. The longitudinal section gradient is even.

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Gorge A gorge is the typical steep canyon of mountain regions, having very steep, and sometimes even overhanging, walls. The valley floor of the gorge is completely occupied by a river.

U-shaped valley A U-shaped valley is a valley transformed by glacial action. Its lower sections have a U-shaped cross section, and its upper sections are V-shaped.

Braided river valley The braided river valley is a long, extended, concave landform. The cross section reveals a wide flat floodplain, which is home to a meandering river bed. The bordering hillsides are convex. “Braiding” refers to the way the meandering river splits into small streams and then comes together again.

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The Basics of Site Grading

“Practice makes perfect” is a justifiably popular phrase in the site grading profession. The following pages will familiarize you with some of the basics. Exercises at the back of the book will help you put into practice everything you learn in this chapter. Small and Large Scale The terms “large scale” and “small scale” come up frequently during project meetings. Have you noticed that many professionals actually use these terms incorrectly vis à vis their cartographical meaning? Here is what you should know. Plan drawings are the basic tool of a designer. Scale was first used in cartography and drawn in maps before anyone had ever dreamt of zoning or detailed design plans. It is therefore cartography that provides the correct definition of large and small scale. A definition that should be used both verbally and in writing. Scale describes the relationship between two points on a map (or plan) and the actual distance in nature. For example, a scale of 1:100 means that one unit on the plan corresponds to 100 units of the same size in nature. The bigger the scale, the closer it approaches actual size. Plans with a small scale (meaning a larger number in the ratio) show larger parts of a project. They are less detailed than large-scale plans. Thus, a plan of 1:10 is larger scale than a plan of 1:100. Put simply, the rule is: large scale = small area, small scale = large area. Typical scales for construction documents are: 1:1 – 1:5 – 1:10 – 1:20 – 1:50 – 1:100. Typical scales for site grading are: 1:100 – 1:200 – 1:500 – 1:1000.

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Land use plan, scale 1: 5000–small scale (the scale corresponds to the original drawing).

Detail drawings, scale 1:10/20/50–large scale (the scale corresponds to the original drawing).

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Slope in percent, ratio and angle.

Slope What is the difference between grade, slope, ratio, and angle of incline? Generally speaking, there is none. These terms are different ways of defining an inclination. A bit more clarity will be shed on this terminology below. Slope Calculations in Percent Mathematicians speak of slope, which is represented using the letter m. In the Cartesian coordinate system, which uses a horizontal x-axis and vertical y-axis, the two points P1 and P2 are defined in coordinates as follows: P1 = (x1,y1) P2 = (x2,y2) The slope of the line connecting points P1 to P2 can be calculated using the following formula: m=

y1 - y2 difference in y = x1 - x2 difference in x

Water needs a gradient in order to drain away from plazas, paths, and built structures, which is why landscape architects always speak of gradient. As in slope, gradient is denoted as g, the ratio between ∆h, the height difference between two points, and ∆l, the length or distance between two points. The value g is multiplied by 100 to obtain gradient as a percentage. g = ∆h : ∆l g = g * 100 % These two conversion formulae are very useful: ∆l = ∆h : g ∆h = g * ∆l

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A sample calculation for gradient in percent.

Ratio The gradient of a hill can be denoted as a ratio. The height difference is given before the colon, and the horizontal distance after the colon. Common ratios are: 1:1, 1:2, 1:3, 2:3. 1:1 1 : 1.5 1:2 1 : 2.5 1:3 1:4 1:5 1:6 1 : 6.6

= 100% = 66.6% = 50% = 40% = 33.3% = 25% = 20% = 16.7% = 15%

1 : 8.3 1 : 10 1 : 12.5 1 : 16.7 1 : 20 1:5 1 : 33.3 1 : 50 1 : 100

= 12% = 10% = 8% = 6% = 5% = 4% = 3% = 2% = 1%

Ratios and their percent gradient.

Ratios and corresponding percentage gradient.

Angle of Incline The angle of incline of a plane can be calculated based on the x-axis. In civil engineering this is termed “embankment angle” and can be used to compute earthwork calculations for the design of dams, road embankments, construction trenches and utility trenches. Angle of incline for the most important grade ratios: 1:3 1:2 1 : 1,5 2:3 1:1

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= 18.4° = 26.6° = 33.7° = 33.7° = 45.0°

Funneled slope to a single lowpoint.

Pitched slope with a single plane.

Reversed pitch with longitudinal fall.

Reversed pitch without longitudinal fall.

Gradient Formations Three forms of gradient are possible for hardscape drainage: — funneled slope, — pitched slope, — reversed pitch, with or without fall. Hipped roof slopes, reversed funnels, and reversed roofs are drainage forms that do not commonly occur in hardscape drainage. The following profile types describe roads and paths: (illustrations see next page) — soft crown, — sharp crown, — pitched slope.

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Hardscape surface with several funnel drains and multiple lowpoints.

Hipped roof slope.

Reversed funnel slope with a single highpoint.

Pitched slope without fall.

Road profiles: pitched slope, sharp crown, soft crown.

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Part distance = 3 Total distance = 9 Total change in elevation = 10 Part elevation = x 3: 9 = x : 10 or x = 3.33 Spot elevation = 93.33 m

Interpolation Interpolation is based on the ratio of part elevation to total elevation equalling the ratio of part distance to total distance. Or put more simply, the ratio of the part to the whole. Manual interpolation used to be the chief method used to create contour maps. A uniform grid was laid out on site, and elevations were taken. The grid and elevation readings were then transferred onto a scaled plan and, using interpolation points of identical elevation, were connected, creating the contour map. Several digital methods now replace this onerous process. Instead of calculating slope, interpolation provides an elegant method of finding the elevation of a point between two contour lines. In the example below, we want to find the elevation of point x. Using the formula “the ratio part distance: total distance equals part elevation: total elevation,” we can quickly determine the elevation of the point x.

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Grid and spot elevations from a site survey.

Contour map based on the interpolation of elevations along the grid lines.

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Spot elevations are essential to the construction, not contour lines. However, plans with spot elevations can quickly become confusing. Plans with both contour lines and spot elevations are therefore needed to control the profiles of the levels.

Spot Elevations You will not get far on a construction site using contour lines, because you need spot elevations to get things built. For paths and plazas, spot elevations should be shown at intersections, junctions, buildings, high points, and low points. A “+” or “x” to the left of the number indicates the exact location of the spot elevation in the grading plan. Conversely, an equilateral triangle is commonly used in sections, elevations, and profiles. Depending on the level of precision required, the spot elevations are shown to two or three decimal places, and normally refer to mean sea level. In Germany, the reference datum is the sea level at Amsterdam, and since the end of the 1990s the abbreviation NHN has been used for normal zero level. In Austria, an average value for the Adriatic at Trieste is used and is abbreviated m.ü.Adria. Switzerland and the Principality of Lichtenstein use meters above sea level (m.ü.M.), referring to the sea level at Marseille. Small construction projects may use a local spot elevation as a reference point (for example, a manhole cover, the house entrance and so forth). All other elevations are then given relative to this point. To avoid negative elevations, professional literature recommends using a number with a high, rounded value, for example H = 100 (see Lehr, 2003). Particular attention must be paid to building entrances, as the given elevations can be for either finished or unfinished floor levels. Note: Geographers use the term “invert level” instead of spot elevation.

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Contour lines are always closed; but this may not always be shown within the plan area.

Proposed contours are shown with a continuous thick line, and existing contours are always shown with a dashed line. This grading concept requires “cut and fill.”

Contour Lines Contour lines are the best method for representing three-dimensional landforms in two dimensions on a map or drawing. Contour lines are also very effective for indicating proposed changes to a project area. Imagine you are to design a golf course. It is basically impossible to visualize the design using only spot elevations, whereas with contour lines one can quickly gain a spatial impression of the concept. For landscape architects, contour lines are the essential tool for visualizing and manipulating outdoor spaces. A contour line connects points of the same elevation. The elevation of a given point refers to a reference benchmark or datum. For maps and plans, the reference datum is generally mean sea level. The term isohypse is also used to indicate contour lines. In contrast, isobaths indicate underwater depth lines. The shorelines of puddles, ponds and lakes are visible as contour lines in the landscape. Contour lines are drawn in scale and shown at regular equidistances (intervals) on topographic maps and plans. To improve readability, main contour lines can be shown using lines of greater thickness to differentiate from contour lines of only secondary importance. Contour lines should always be labeled. The base of the elevation label sits on a line or between two lines with its base oriented downhill. If the interval between contour lines is known (for example, 1 meter, 5 meters, 10 meters), a single contour line elevation given on the plan is enough to clearly define in which direction the terrain rises or falls. Existing contours are always dashed; proposed contours are drawn with a continuous line. Both existing and proposed contours should be shown in design and construction drawings, and thus both line types should be present. The perpendicular line between two contour lines is the shortest distance. This path also has the greatest slope. Water always takes the fastest and steepest route downhill; consequently water flows at right angles to contour lines.

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Arrows show the direction of water flow. Water always runs at a right angle to the contour lines.

A shaded model of steps.

The proposed contour lines of a retaining wall run along the wall face.

The contour lines run at even intervals along the steps.

Contour lines are continuous and represent a closed shape, sometimes shown within the extent of the drawing and sometimes not. Accordingly, a single, unclosed contour line cannot lie within closed contour lines. If we want to show high points or low points using contours, the lines will either be closed (even if this occurs outside the limits of the drawing) or run parallel. Contour lines never split. Overlapping only occurs when overhangs are depicted. Spot elevations can be used in addition to contours to indicate changes of elevation between contour lines. If no spot elevations are present, we can assume a uniform and consistent gradient between contour lines. The base line connects the points at which the proposed contour lines meet the existing ones.

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79

Contour lines never split into two lines.

Instead of splitting, they run parallel to each other, even when separated by only a very small distance.

Contour lines cross only when showing the difference between existing and proposed grading or to show an overhang as here.

80

A single contour line that just stops, as shown here, is not possible.

Contour lines are always closed.

In which direction does the terrain rise?

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81

The contour leveling near a road lined with curbstones. When roads and streets are edged with curbstones, the contour lines run along the side of the edging until the level is reached where they lead back to the terrain.

Profile of the street.

The run of the contour lines for a sloped road with a curb.

The layout of contour lines along a curb always appears at first glance to be somewhat complicated. The trick is to systematically calculate spot elevations along the axis. The best way is to start in the middle of the road and draw an y-axis (dashed line) and an x-axis (dot-dashed). The long and cross gradients are defined through arrows and notations. Once the elevations have been worked out along the y-axis, switch to the x-axis and calculate the elevations there. Points of the same elevation produce a profile that can be repeatedly copied if the gradient remains constant along the road.

82

Road detail with a 10 cm curb, an 8.5% longitudinal gradient, and a ditch on the side (with 1 : 2 and 2 : 3 embankments). Spot elevations are calculated for the x-axis (dotted line) and the y-axis (dashed line).

Contour plan of the road with spot elevations and contours.

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83

Dam

Cut Channel

A dam and channel embankment.

shoulder foot

berm crown

floor

cut-away point embankment incline

Embankments A hill is a naturally sloped landform. If a mound is created artificially, it is called an embankment. Embankment forms include dams (filled embankments), channels (cut embankments), and double profiles (half dam with fill, half channels with cut and side cut embankments). The embankment incline is given in degrees from the horizontal, as slope ratio or percent slope. An embankment has a foot or lower edge, sides, and an upper edge. Drainage channels can be found below or above the embankment. Berms are step-like subdivisions of the embankment. They have a width of 1 to 2.5 meters. Berms fulfill the following purposes: — decreasing the earth pressure on the embankment foot, — access paths for maintenance of the embankment, — drainage for high embankments, — anti-fall safety barriers, — interception point for falling material. The embankment angle b is the angle between the horizon of the ground and the line of the embankment. For example, dry sand has a natural angle of repose of between 28 and 45°, depending on density, grain shape, and particle size grading. Embankments with an angle of 2:3 (33.7°) are typical, and are considered stable. If the embankment angle is greater than 33.7° (2:3 or 1:1.5), it is referred to as a steep slope. In this case, stabilization elements are generally necessary, as the proposed slope is steeper than the natural angle of repose (b).

84

The natural angle of repose of gravel.

Embankment lower edge, drainage channel, and embankment upper edge, the Garden terraces of Haifa, Israel.

Binding soils have a higher silt and clay content than other soils. This additional cohesion indicates the ability of the soil particles to bind to one another. If the cohesion of the soil is very high, the embankment angle may exceed the natural angle of repose. Embankment angle b for the most important gradient ratios: 1:3β 1:2β 1 : 1,5 β 2:3β 1:1β

= 18,4° = 26,6° = 33,7° = 33,7° = 45,0°

Grade ratios and correlating embankment angles.

Profile A profile is the side view of the earth’s surface taken along a given plane. In contrast to a section, which includes information about the inner make-up of the cut object, a profile gives information only about the surface. Profiles are drawn to scale based on the plan view. The elevations of the profile plan are commonly enlarged by a factor of ten to make the elevation differences more pronounced. The vertical increase is expressed as follows: Vertical exaggeration = horizontal scale / vertical scale

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85

Digital longitudinal profile of a proposed stream with a vertical exaggeration of 10:1.

Manual preparation of a profile.

For example, a profile with an exaggeration of 10:1 has a horizontal scale of 1:1000 and a vertical scale of 1:100. In road construction, profiles are called gradient diagrams. However these are not to be confused with grading and layout plans in landscape architecture. Longitudinal profiles of roadway alignments are based on the central axis of the road. This line is defined as a gradient and is broken into 20-meter sections. The sections are called stations, and often start with the station 0 + 000.000 = 0 kilometers. The curvature string is a schematic representation of the alignment elements (lines and curves) with the stations and, in road projects, is located below the gradient diagram. A technical profile drawing should always include the following: — reference elevation, — profile number, — scale (scale exaggeration, where relevant), — existing elevations, — proposed elevations, — horizontal and vertical stations, for example 0+25, — changes in direction. To prepare a profile manually, the following steps are necessary: 1. Connect two points on a map with a line. 2. Define the highest and lowest points. 3. Label and draw horizontal elevation lines on the new profile drawing. 4. Orient the map to the profile drawing. 5. Draw perpendicular lines from the contour line to its relevant horizontal line on the profile drawing. 6. Connect the points of intersections, creating the profile.

86

The base line connects the points where proposed and existing contour lines intersect. This is an example of balanced cut and fill. The base line also functions as the axis beyond which the cut material can be dumped in the fill area.

Cut and Fill Calculations How much does it cost to remove a cubic meter of soil? The operator of a Swiss landfill charges CHF 7.50 per clean tonne of soil material. The specific weight of a cubic meter of soil is 1.8 tonnes, making the disposal costs of a cubic meter of excavation material CHF 13.50 (€11 or about $12). If the cut material can be re-used on site for fill, so that no soil needs to be transported to or from the site, we call it balanced cut and fill. It is always worth trying to balance out the cut and fill to keep costs down. Volume Calculations Using Profiles A trapezoid is a geometric shape with a parallel base and top. A road can be thought of as a series of trapezoids. The trapezoid formula is a helpful method of calculating the volume of long objects. It is assumed that the terrain runs straight from profile to profile. The profiles are parallel to one another and are always at a constant distance of d. A1 and A2 indicate the profile surface areas. The surface area of an intended profile in the middle is called Am. Using this data, the volume between the profiles can be calculated. d (A1 + 4Am + A2) Trapezoid formula: V = 6 * The area between the first and last profile and the existing terrain are remainders and their volume can be calculated using the following formula: V=

A d 3 *

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87

Calculation of earth volumes using the approximation formula:

(

Example of volume calculation from contour lines using the approximation formula:

)

V= 50 * A + A+B + B+C + C 3 2 2 3

(

V= 2 * A + A+B + B+C + C+D + D 3 2 2 2 3

)

To calculate the surface Am, their basics points must be averaged between corresponding points of adjacent cross sections. This calculation is complicated, so we use the following approximation formula, the two remaining peaks are likewise included in the calculation: V=d*

(

A1 + A2 A1 A2 + + 3 3 2

)

Volume Calculations Using Contour Lines This is perhaps the quickest analog method of determining volumes, as it can be done using only a plan, with no need to generate profile drawings. However, a correct set of existing and proposed contour lines is essential. In principle, volume calculation using contour lines relates directly to volume calculation using profiles. The interval between the contour lines corresponds to the distance between profiles; the surface area between the existing and new contour lines is one such profile. The above-mentioned trapezoid formula can therefore be employed. Calculating Volume with Triangular Prisms The triangular prism method of calculation is used in digital terrain models (DTM). A differential DTM is triangulated based on an existing DTM and a planned DTM. This creates numerous triangular prisms. The prisms can be used to determine the volume by means of volume calculations. This method creates very accurate flow measurements. However, the profile method provides better verification and control.

88

Calculation of earth volumes using the prism method.

Digital terrain model of the Ravensburger Playland project. Design: Rotzler Krebs Partner Landschaftsarchitekten BSLA. DHM: Peter Petschek.

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89

Grading: Purpose and Techniques

The Purpose of Site Grading Every landscape architecture project, whether it is a big development or small domestic garden, deals with changes to the site’s surface. A good, restrained grading concept will determine whether a project is successful or not. Too little gradient and water will puddle, possibly penetrating into built structures and causing frost and meltwater damage. Conversely, overly steep gradients can lead to landslides and soil erosion, both of which can cause enormous damage. We all know of projects where buildings, roads, and other infrastructure are poorly integrated into the landscape. Integration, or rather accentuation through site and vegetation, improves landscape character. The three main focuses of site grading are as follows. Creating Level Space Seating areas, parking lots and sports facilities all need level space. The term level is not entirely correct: These level spaces also have an internal grade so that water can drain away. Circulation Roads and paths connect point A to point B. Roads and paths generally have slopes. Embankments are used to create an interface with the existing site. Standard gradients for roads and pavements, as set down in building and engineering codes, should be observed. Natural Grading Geometric or naturally landscaped hills, swales and depressions create accents. They are important design elements in landscape architecture. The task of collecting and infiltrating rainwater in depressions without outlets (hollows) and open ditches with a slight gradient (swales) has gained increasing importance in recent years.

90

A level seating area.

Accessing a lookout hill via a path graded into the site.

Natural site grading with a swale and hollow for rainwater infiltration.

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91

Creating level space for a building using site grading.

Site grading is always part of designing circulation.

Depressions and swales can serve both as design elements and water infiltration infrastructure.

92

Private garden on the outskirts of Dubai. Landscape architect Heiko Heinig, Orient Irrigation Services, Dubai.

Al Hamra Golf Course, Ras al-Khaimah, United Arab Emirates. Golf course architect Peter Harradine, Harradine Golf, Dubai.

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93

Important Criteria There are many important criteria that must be kept in mind while developing a grading concept. The most important points to ensure functioning site grading are: 1. The grading around buildings should always be orientated so as to fall away from the building. 2. Level areas with standing water should never be allowed to occur. 3. Site grading extends only to the site boundaries. 4. The grading concept always begins with the elevations of existing buildings, roads, or paths. 5. An initial grading concept on sketch paper with contour lines should be further developed in parallel with the overall design and drainage concept. The end result should be a grading and layout plan with existing and proposed contour lines, spot elevations, gradient indications, grade parting (crown) lines, and the layout of all important construction elements. 6. The maximum and minimum gradient of various surfaces must be observed (see the grading guidelines on the next page). Gradients of four percent and above are visible to the naked eye! A manual lawn mower can only be used on gradients up to 26.6° (1:2 or 50%). Manufacturers of ride-on mowers recommend a maximum of 10° because of the mowers’ high center of gravity. Special mowers are used for steeper embankments. 7. Spot elevations should always be shown at the following locations: — corners of buildings, entrances to buildings, — all corners of parking lots, — terraces and other paved surfaces, — at path/pavement intersections, — at the top and bottom of steps and walls, — drain inlets and high and low points. Spot elevations are more important than contour lines. 8. The throughfall is the line resulting from the vertical continuation of the edge of the tree’s crown downward towards the ground. Trees require a protection area of the crown’s extent plus 1.5 meters outward. No grading should ever take place within this area.

94

Minimum and Maximum Slopes Type

minimum slope

maximum slope

Roads / Pavement / Plazas road longitudinal gradient, 30 km/h speed limit road cross gradient, 30 km/h speed limit pedestrian path longitudinal gradient

0.5% 

12%

2% 

7%

–

10%

pedestrian path cross gradient

1%

4%

disabled access ramp

6%

8%

parking longitudinal gradient

1%

5%

parking cross gradient

1%

10%

seating area

1%

2%

service area

1%

8%

Planted Areas football field (competitive) grass play area (non-competitive) lawn

0.5%

1%

1%

5%

1%

25%

0.5%

10%

embankments with normal soil

–

66%

embankments with poor soil

–

50%

planting areas

drainage channels longitudinal gradient

1%

8%

drainage channels cross gradient

2%

25%

drainage swales cross gradient

2%

10%

Paving natural stone slabs and pavers, sawn / flamed natural stone slabs and pavers, split concrete slabs and pavers, sandblasted exposed aggregate concrete slabs in situ concrete, lightly structured in situ concrete, rilled

Gradient Standard Guidelines.

1% 2% 1.5% 2% 1.5% 2%

crushed limestone/compacted chipping surfaces

1.5%

grasscrete pavers

1.5%

asphalt

1.5%

protective matting surfaces

1.5%

Site Grading and Architecture The precise siting of architectural elements is a necessity. There are several ways in which the base of a building can be inserted into the terrain in relation to the existing site: — as a cut, — as a fill, with the foundations as the spatial edge, — as a combination of cut and fill.

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Siting the building as cut.

Siting the building as fill with the foundations as the spatial edge.

Siting the building as a combination of cut and fill.

The pros and cons of each variation should be looked at in relation to the architectural expression of the building, its spatial and internal organization, circulation, and so on. The overall effect of the building in the landscape is equally important. Approach to a Grading Plan On a southwest-facing slope, a building is to be constructed centrally on a terrace. The terrace edge has a finished height of 37.4 meters. Grade the terrace with a ten percent gradient in the available area. As the project progresses, a gradient would of course be planned for the terrace. Additional exercises can be found in the appendix.

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Laborers’ cottages in Beregg, Zurich Oberland, Switzerland.

Farmer’s house in the drumlin landscape near Menzingen, Canton Zug, Switzerland.

Farmer’s house in Oberegg, Etzel, Canton Schwyz, Switzerland.

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Chapel designed by Mario Botta on Monte Tamaro in the Canton of Ticino, Switzerland. A long walkway, supported by two walls, leads to a plateau overlooking the Magadino Plain, which lies deep in a valley. A second access walkway within the two walls forms a flight of stairs that climb up from the natural terrain.

Herzog & de Meuron along with Ai Weiwei designed the Serpentine Gallery Pavilion in 2012. Placed at irregular intervals, twelve cork-covered steel columns support a round steel roof, which also forms a shallow pond twenty-five millimeters deep. Beneath this, the foundations of the previous Serpentine Pavilion offer seating options, covered with wood and steampressed cork. The restricted field of view from the pavilion, which is cut into the ground, offers new and unusual views of Hyde Park.

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Paul Klee Center, Bern, Switerland. Architect: Renzo Piano. “It was clear to Piano from the beginning that the artist Paul Klee ‘needed to take in more air and breathe more deeply’ than he would be able to if locked inside a ‘normal building.’ As for the vision of his own work, Renzo Piano was also inspired by the identity of the site and the lines of its softly curving terrain.” From: www.zpk.org, architecture, Die Idee, 2012).

100

Paul Klee Center.

The Basics 101

Grading and Layout Plan A grading and layout plan is an essential tool for transferring a design from the drawing onto the construction site. Such plans provide scaled spatial definition in plan and elevation. Using the layout plan, the contractor should be able to stake out everything that is to be constructed on site. Since the drainage elements, such as gutters, manholes, and pipes, must also be localized, this information is often integrated into the plan. This would then be a height, surveying, and drainage plan.

Initial situation with existing contour lines and the terrace.

The alignment of the terrace was extended and then used as a basis for calculating the planned heights. The remodeling of the gradient formula used: Δl = Δh : g.

After entering the levels on the plan, the spot elevations were raised to the same levels as the proposed contour lines and connected to them.

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Section of an earthwork plan (at 5-meter intervals) with existing levels, proposed levels, and level differences. These three points are essential if not working with a GPS machine control system.

Digital levels, grades, and drainage plan (Civil 3D) with coordinate dimensioning (students of HSR – University of Applied Sciences Rapperswil).

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Chain dimensioning is the correct dimensioning style for building construction. It is composed of individual dimensions, part dimensions, and total dimensions.

Running dimensioning is good for garden and landscape construction, as the numerical values never need to be calculated on site.

Using easy-to-use total stations, non-surveyors can now also use coordinate dimensioning to stake out.

The main purpose of the grading and layout plan is to give the appointed contractor a simple and precise overview of essential dimensions. The landscape architect must consider carefully which dimensions are necessary and which are redundant. You should never double up on dimensions or provide too many. The intended communication of the plan is best achieved when the given dimensions are limited to the least, but most efficiently organized, data. The three most important dimensioning systems used in grading and layout plans are: chained (consecutive), running, and coordinate dimensioning. It makes sense to differentiate between fixed, partially fixed, and flexible areas in the layout plan. Fixed elements such as buildings, site boundaries, or benchmarks are not dimensioned. They either already exist in the project area or will be erected at exactly the right spot. Proposed buildings are defined during construction using a tensioned line or marker pegs. The staking out by a surveyor provides the contractor with flight lines and the extents of the building. Once the building has been erected, the surveyor returns to survey the building to update official records (property, cadastral, and local land survey). This record will help you to detect errors, which fortunately rarely occur. Walls, steps and trees can be staked out using the building marker stakes as a reference.

104

Plan example of running dimensions.

Plan example of chained (consecutive) dimensions.

The Basics 105

Stake out markers define the precise location of the building.

Right: Digital levels, grades, and drainage plans (Civil 3D) with coordinate dimensioning (students of HSR – University of Applied Sciences Rapperswil).

Partially fixed elements such as walls, steps and trees are referenced to building edges, boundary markers or coordinates. Fundamental landscape architecture elements such as paths, walls, and steps can best be defined through a central axis with perpendicular width values. Flexible areas and objects do not need dimensioning. For example, if the beginning or end of a path is clearly defined, a numerical value for its length would only add confusion. Big earthworks projects, such as golf courses, or parks with large bodies of water and hills, need their own earthworks plans. Earthworks plans should always include an elevation grid. The grid size depends on the required grading and the scale of the project. The following information should always be included in an earthworks plan: — existing elevations, — proposed elevations, and — the difference between the two.

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The Basics 107

Landscape Stabilization

Two terms define sloped landscape elements: — hill and — embankment. While the word “hill” describes a natural landform, “embankment” refers to an artificial earthwork structure. There is no particular reason for this differentiation in terms of structural stability. Regardless of whether it is part of a hill or an embankment, soil will slip or collapse when the incline of the slope exceeds the shear strength of the soil material. Landslides and soil erosion can cause devastating catastrophes. The following pages give an overview of soil stabilization construction techniques used to prevent soil slips and erosion. Soil Geotechnology differentiates between unconsolidated rock and bedrock. Types of bedrock range from granite to conglomerate (nagelfluh), where the microstructure is durably bonded by minerals. Unconsolidated rock can be subdivided according to particle size. The following particle diameters define six mineral size classes: — clay less than 0.002 mm, — silt 0.002 to 0.06 mm, — sand 0.06 to 2.0 mm, — gravel 2.0 to 6.0 mm, — cobble 6.0 to 200 mm, — boulder larger than 200 mm. A particle distribution curve indicates the sum total of a sieved material, shown as particle size distribution. Using these measurements and other criteria, a given soil can be categorized into a class of soils having the same or similar characteristics. The loadbearing capacity, workability, and frost and water capacity of soils can be estimated based on the soil class. In practice, geotechnical laboratories carry out testing and give on-site recommendations as to the workability and stability of the soil. Naturally occurring soil “grows” over thousands of years, forming soil horizons of: (a) topsoil, (b) subsoil, and (c) substrate. The substrate is composed of either unconsolidated or consolidated rock, without soil accumulation or the presence of biological activity. The transitional layer is of weathered base material, which is usually well interspersed

Landscape Stabilization 109

slimes clay 100

sieving grain

silt medium

fine

large

Mass proportion of grains in % of total

90

fine

large

gravel medium

fine

stone

large

0 10

risk of frost

low risk of frost

80

sand medium

20

risk of frost

70

30

60

40

frost-proof

50

50

40

sensitive to frost

60

30

70

20

80

10

90

0

0.001 0.002

0.006 0.01

Particle size distribution chart showing frost-proof and frost-susceptible soils.

0.02

0.06

0.1

0.2

0.6

1

2

6

10

20

60 100

100

grain diameter in mm

with roots. This is the subsoil, which extends to depths of 50 to 150 centimeters. The topsoil layer is organically active, rich in humus, dark-colored, and usually includes extensive root development. The topsoil is normally between 5 and 40 centimeters thick. Soil that is to be excavated, transported, distributed, and driven on should be treated as follows. — Soil should be excavated and deposited only if the soil water tension level equals ten centibars (cbar). Soil water tension is the energy needed to hold back the water in the soil pores and surfaces. The drier the soil, the greater its water tension. This measurement is of central importance when making or altering earthworks, because of the soil’s load-bearing capacity and how that relates to its degree of dampness. Soil water tension is measured with a tensiometer. – 0 to 6 cbar = wet soil – 6 to 12 cbar = damp soil – 12 to 20 cbar = damp to drying soil – over 20 cbar = dry soil, ideal to be worked. Practitioners warn against walking on, driving on, or working the soil when it is kneadable (plastic). — Wheeled vehicles should be used only on the substrate or on defined circulation tracks. — Drainage must be provided while the earthworks projects are being carried out. — The difference in pH value between the topsoil and subsoil must not exceed 0.7 pH units. Using soils with greatly differing degrees of acidity results in very different soil solution environments, and may restrict plant and root growth. — Soil should be laid down in layers no thicker than 0.5 meter, and each layer should be compacted (see FaBo, Fachstelle Bodenschutz, Canton of Zurich, 2003).

110

Sieving tower used to determine soil particle size distribution.

For the interim storage of soil: — Drainage must be provided. — No other materials should be stored at the interim soil storage area. — The soil should not be driven over. The soil should be loosely piled up and immediately planted with vegetation. — The maximum height for stockpiling topsoil is ≤ 2.5 meters for interim storage of less than one year and ≤ 1.5 meters for storage lasting longer than one year. — The maximum height for stockpiling subsoil varies from ≤ 1.5 meters for delicate soils to > 2.5 meters for more robust soils. — Topsoil and subsoil should be excavated separately and stored separately. — Mixing clean soil with polluted soil should be avoided (FaBo, 2003). Excavating soil changes its volume. For topsoil, an expansion factor of 1.2 is used for the transition from a dense to a loose state. The expansion factor for subsoil and substratum is approximately 1.3. When topsoil has been redistributed it will settle and compact naturally, its volume changing by a factor of 0.85. Newly laid subsoil and substrate have a settling factor of 0.75. Clean sand and other frost-proof materials used for the base course have the following expansion and settling factors: solid – loose 1.25 and loose – solid 0.8.

Landscape Stabilization 111

A tensiometer used for measuring soil water tension.

Erosion and Landslides

Erosion Erosion and landslides are the two main dangers in site grading. “Erosion,” in contrast to “soil erosion,” is the natural weathering process of rock on the surface of the earth. Soil erosion means the movement and transfer of soil caused by humans. Mechanical erosion, water erosion, and wind erosion are three additional types of erosion. Plowing and the compaction of a site by hikers or grazing animals cause mechanical changes. In steep meadows in the Alps, animals tend to walk in tracks parallel to the slopes. These animal tracks are an example of mechanical soil erosion; soil researchers call them track slips (Trittblaiken). Water erosion is triggered by heavy and extended rain events. A closed vegetation layer restricts water erosion. On a construction site, plastic sheeting does the job of protecting excavations from water. Fine, sandy soils are particularly susceptible to wind erosion; sand dunes are one result. Windbreaks such as natural stone walls or plantings are used in many countries to protect against wind erosion. Landslides The earth’s gravity is the cause of landslides, for as soon as its shear resistance is too low, soil moves downward. “Landslide” is used in geotechnology as an umbrella term for damage caused by soil breaches. Geotechnical scientists differentiate the downhill movement of soil into different categories: topsoil landslides, translational slips, slumps, and shear failure. Common causes of landslides are: — infiltration of surface water, — very steep inclines,

112

These animal tracks in the Tössbergen, Switzerland, are an example of mechanical erosion produced by animal grazing.

Even excavation sites sometimes look like works of art. The plastic wrapping is for protection against water erosion.

Sand dunes produced by wind erosion.

Landscape Stabilization 113

A falling wall in the form of a translation slide, a rotational slide, or a slump (from left to right).

— excavation at the foot of an embankment, — tremors, earthquakes, — too much weight on the crown of the embankment or earth structure. Suitable countermeasures should be coordinated with a geotechnical engineer. Careful attention should be paid to all construction measures. Every large site-grading project should start with a geotechnical survey.

Embankment Angle and Construction Technology Depending on the embankment’s angle of slope, the following construction methods are appropriate for stabilizing embankments and hillsides. 0° to 33.7° Stabilization measures are not needed at this relatively low range of steepness. However, even the flattest slope needs vegetation. The standard slope of normal soil type embankments in road construction is around 33.7 degrees (2:3). Temporary erosion protection is recommended (using, for example, a natural textile) to get vegetation established as soon as possible. 33.7° to 45° An incline angle between 33.7 degrees (2:3) and 45 degrees (1:1) requires soil stabilization. Bioengineering construction methods or soil reinforcement with surface protection are suitable.

114

Embankment stabilization works on a bypass, Canton of Zurich, Switzerland.

45° to 70° An embankment angle greater than 45 degrees is referred to as “oversteep.” Reinforced earth, geotextile walls, and to a certain extent bioengineering construction techniques, are appropriate stabilization methods. 70° to 90° Only a retaining wall can stabilize a slope with an angle of incline between 70 and 90 degrees. An Overview of Slope Stabilization Construction Techniques Various stabilization techniques can be employed to reduce erosion and landslides in site grading. The author urgently reminds the reader that the following construction techniques should only be used in consultation with professional experts: — bioengineering construction methods (soil protection and ground stabilization methods), — lime and cement stabilization, — reinforced earth, — geotextiles, — retaining walls (gravity and cantilever).

Landscape Stabilization 115

Embankment stabilization using coconut netting, ZurichLeutschenbach (dipol Landschaftsarchitekten).

Bioengineering Construction Methods Bioengineering combines technical and biological knowledge. Plants take center stage. Plant roots do more than take up nutrients; their root systems also stabilize the soil. Some plants reproduce asexually: cuttings are planted, and by the next spring leaves uncurl on the thin saplings and new roots have already anchored into the soil. In this special area of landscape architecture, plants not only have an esthetic and ecological function, but also serve as a primary construction material to conserve soil. We refer to this as live implementation. Construction methods that use living material are complex and depend heavily on local habitat factors such as soil, water, climate, and the availability of local vegetation. Numerous publications deal with this topic skillfully and in depth. This section of the book is merely a brief introduction to the subject. If bioengineering construction methods are to be employed, study of technical literature (see Zeh, 2007) and consultation with local professionals are an absolute must in order for the project to be implemented successfully. Bioengineering applies soil protection methods to protect against soil erosion, and ground stabilizing techniques to prevent landslides.

116

Embankment construction on the Birs River using branches of willow by landscape architecture office Geitz & Partner.

Soil Protection Techniques Soil protection techniques protect the topsoil layer from erosion. They include the following four general categories: — Live brush mats : Branches are laid down closely packed, with their thicker end pointing into the ground so that they can sprout. They are also secured with wooden stakes and wire, and then covered with earth, leaving ten centimeters showing. — Erosion protection mats and nets : Erosion protection mats are usually seed mats constructed of two layers with the seed held between. Once the mats have been spread out over the embankment surface, stakes or pegs are used to anchor the mats to the ground. The same method is used for nets: biodegradable geotextile netting products cover the embankment and protect seeds and seedlings from being washed away. — Seeding : The simplest kind of embankment stabilization is seeded turf or grass. The ideal sowing period extends from the beginning of April to mid-June and from the beginning of September to mid-October. Installing turf mats or rolls is expensive, but very effective. — Wet seeding/hydroseeding : A mixture of seed, straw (for mulch) and adhesive is a surface treatment method typically used to vegetate road embankments. A mixing tank mounted on a truck mixes environmentally friendly adhesive, meadow or shrub seeds, fertilizer, soil improvement compost, and water. The mixture is sprayed onto the embankment using a high-pressure hose. In step two, the embankment is covered with straw. Mounted on the back of a truck, a large pneumatic pipe blows straw onto the artificial bank. Step three is to spread an additional layer of adhesive onto the straw to secure it to the ground.

Landscape Stabilization 117

To build a wooden stake fence, a structural frame of trunk sections is used in addition to sprouting branches to stabilize the embankment. A restoration project designed by the landscape architecture office Geitz & Partner.

The completed project.

Ground Stabilization Techniques The purpose of ground stabilization construction methods is to prevent landslides. The methods are complex and are used only by specialist planners working with specially equipped landscape contractors who are able to carry out the construction procedures in extreme locations, such as in the mountains or on hydraulic engineering projects. Ground stabilization methods include layering, wattle fences, fascines, and wooden stake fences. In layering, there is a difference between brush layering, hedge layering, and a combination of the two. The construction materials in brush layering are branches that are capable of sprouting, whereas rooting shrubs are used for hedge layering. The plant material is planted in stepped trenches, where the earth material of the upper trench is used to backfill the trench below, including the plant layering material. About ten centimeters of the plant material should be visible once the trench has been backfilled. Flexible willow lengths or other sprouting rods are used to make wattle fencing, which is secured with wooden stakes. Rods are also used to build fascines: bundles of long rods are laid in trenches, secured with wooden stakes, and then covered up with earth. This construction technique originated in Italy and has been used in hydraulic engineering projects for hundreds of years. [As an aside, in ancient Roman times the fasces was a bundle of rods with an ax, which officials carried in order to make way for important dignitaries. The term fascism finds its origin here as well.]

118

Wet seeding or hydroseeding: Step 1: Spraying on the seed mixture.

Step 2: Shooting on the straw.

Step 3: Anchoring the straw with adhesive.

Landscape Stabilization 119

Ivy-covered embankment, Baha’i Terraces and Gardens of Haifa, Israel.

Embankment maintenance, Baha’i Terraces and Gardens of Haifa, Israel.

Stabilization Using Lime and Cement Using lime and cement to stabilize the ground is not new in road and earthworks. The Romans mixed puzzolanic material into their roads. Pozzuoli is a small town at the foot of Mount Vesuvius, where volcanic ash has been mined since ancient times. The ash has characteristics similar to cement and was used in the production of concrete (Latin: opus caementicium). A gravel and sand aggregate is the ideal material for road foundations. However, massive amounts are needed. Gravel and sand aggregates have the important ecological function of acting as a storage medium for ground water. As good aggregate becomes increasingly expensive and as the transportation of large quantities is harmful to the environment, lime and cement are increasingly being used to strengthen soils that are naturally unstable. Soil stabilization makes it possible to use cohesive (binding) and wet soils. The addition of lime has an immediate effect on soil structure. In the long term, the hydrological and frost stability of the soil improves. Lime is used to stabilize clay soils, whereas cement is used to stabilize gravelly-sandy soils. A combination of lime and cement additives is appropriate for silt or silty sand. Personnel who come into contact with unslaked lime (calcium oxide) during the onsite mixing and installation procedures must wear protective clothing. In particular, the mouth and eyes must be protected. As a consequence, only contractors with specialist equipment use this technique. Lime stabilization is also sometimes used to waterproof pond bottoms and embankments.

120

The BMX-Club “Grab on Kids” in Volketswil near Zurich wanted a new racing track. ARGE KIBAG/Innauen + Koch built the project in the spring of 2005. About 12,000 cubic meters of excavation material was used for the subgrade earthworks of the obstacle course, which is 380 meters long and between 5.5 and 10 meters wide.

The excavation material was graded into rough mounds by a 30-tonne excavator. After lime stabilization and compaction, smaller diggers were used to shape the professional standard race track.

The surface material is finely crushed stone of 0 to3 mm. The fine crush was mixed with water and applied like a thick paste, then compacted using a vibrating plate.

BMX test run.

Landscape Stabilization 121

SYTEC TerraMur with the folded-up geogrid used as mechanical stabilization. The side of the existing embankment must always be provided with drainage.

Reinforced Earth When used in combination, metal reinforcing mesh, geogrids, and fill material are known as “reinforced earth,” “mechanically stabilized earth structures,” or “terre armée.” In addition to being more economical than concrete constructions, reinforced earth constructions also have the following advantages: — high loadbearing capacity, — not susceptible to subsidence, — quick installation (60 square meters per day is normal), — earthquake resistant, — existing excavation material can generally be used, and — no limit to the maximum built height. SYTEC TerraMur is a popular reinforced earth system in Switzerland. The galvanized or non-galvanized reinforcing meshes are inclined between 60 and 70 degrees. Brackets ensure that the angle of inclination is maintained. Geogrids are synthetic mats and are attached mechanically to the steel reinforcing mesh. Once the geogrid has been laid out and covered with backfill, it is then folded up. The anchoring of the fill material in the webbing of the synthetic mats distributes tensile stress while acting as erosion protection for the front edge. There is a difference between front fill and backfill. Front fill material should be excavated earth without coarse granules and without organic material. A gravel and sand aggregate makes the most suitable backfill material. Drainage behind the stabilizing reinforcement is essential.

122

TerraMur with TerraGreen vegetation.

TerraMur after half a year planted with a low-maintenance extensive grass mixture.

Landscape Stabilization 123

To stabilize an embankment, geotextile retaining walls made from stacked layers can also be built using natural fibers (coconut). A project by the landscape architecture office Geitz & Partner.

Geotextiles Geosynthetics are made from a polymer-based material. They come in various forms, including geotextiles, geonets, and geogrids. Commonly used in geotechnology, these products have special functions, for example: separation, filtration, drainage, reinforcement, protection, waterproofing, and erosion protection (Rüegger/Hufenus, 2003). There are also biodegradable geotextiles made from raw materials such as coconut, flax, cotton, and jute. Natural-fiber slope stabilization materials remain functional for about one year, which is the time normally needed for roots to become established. Geosynthetic textiles last for more than ten years. Geotextile retaining walls work on the same principle as reinforced earth. With the folding up of the geotextile sheet on the outer front, the geotextile wall looks like a long, multi-layered piece of upholstery. So they are sometimes called “geotextile barrels.” The geotextile takes on the reinforcement function of the earth structure. The surface of the geotextile retaining wall must be vegetated, using either spray seeding or lines of shrubs. Depending on the fill material, angles of incline up to 60 degrees are possible.

124

A gravity wall is kept stable by its own weight. With a cantilevered wall, the counterweight of the earth on the foundation foot makes it stable.

Retaining Walls Basically, retaining walls are divided into cantilevered retaining walls and gravity retaining walls. Both wall types need frost-proof foundations and natural soil or they will not be stable, because of frost heave and thaw settling. The accumulation of ice expands the soil and causes heave. During the subsequent thaw periods, the water content of the soil will change. This can result in uneven settling. In the lowlands in Switzerland, frost reaches down to 80 centimeters. High mountain areas more than 1500 meters above sea level have a frost depth of up to 250 centimeters. Cantilevered Retaining Walls Cantilevered walls are relatively thin, and are suitable for large changes in elevation. The earth under the cantilever foot gives the wall stability. However, this stability depends on a wide cantilever foot on the embankment side and a lot of earth movement compared to a gravity wall. The wall should always be reinforced: the wall may be slim with very low concrete mass, but it must be high-strength. Cantilevered retaining walls can be built vertically or leaning back towards the embankment. The base and foot of the wall should have a slope of ten percent to allow water to drain away from the substructure. Gravity Retaining Walls The classic concrete gravity retaining wall has little or no reinforcement. The strength of the concrete is low, as is the width of the foundations, and the amount of excavation required. The large quantity of concrete required must be mentioned as a disadvantage. Gravity retaining walls are suitable for good load-bearing soils and have a tapered incline of between 5:1 and 10:1. As a rule, the width of the foundations (W) is 40 to 50% of the height (H), even in level sites. The category of gravity retaining walls includes: (i) gabions, (ii) stone block walls, (iii) pre-cast element walls, and (iv) natural stone walls.

Landscape Stabilization 125

p

p

p

n

H

h

Calculation of the foundation foot width of a cantilevered retaining wall (Baukader Schweiz 2006, pp. 198–201).

0.00 m

Terrain

-0.80 m

w

w1

W

soil type

b

g [kN/m3]

humus

0.41

18

sand / gravel, moist loam / clay up to 4m loam / clay over 4m

0.33

18

0.41

21

0.49

20

formula for cantilevered retainig wall with cutoff formula for cantilevered retainig wall without cutoff

b (Beta) – slope angle g (Gamma) – moisture densitiy of th soil p – load p = 3.5 kN/m2 – car p = 5 kN/m2 – storage area p = 3.5 kN/m2 – truck n – width of wall n= 0.25

H´ = p : g w=

H * b * (H + 3 * H´) [m] 1+ 4 * n

w=

H * b * (H + 3 * H´) [m]

cutoff w1 = n * w [m]

W = (1+ n) * w [m]

example: clay soil, wall height H = 3.0m, p = 5kN/m2, cantilevered retainig wall with cutoff H´ = 5 : 21 = 0.24m

126

w=

3.0 * 0.41 * (3.0 + 3 * 0.24) =1.51m 1 + 4 * 0.25

cutoff w1 = 0.25 * 1.51 = 0.38m W = 1.89m

I w = W/3

II w = W

IIIw = W/2

IV w = 2W/3

H

n

I w = W/3

II w = W

IIIw = W/2

IV w = 2W/3

H

n

w

w

W

w

W

w

w

W H

I

II

III

IV

6.00

3.29

3.29

2.98

2.90

5.50

3.02

3.02

2.74

2.66

5.00

2.74

2.74

2.49

2.42

4.50

2.47

2.47

2.25

2.19

4.00

2.19

2.19

2.00

1.95

3.50

1.92

1.92

1.76

1.71

3.00

1.65

1.65

1.57

1.47

2.50

1.37

1.37

1.27

1.24

2.00

1.10

1.10

1.02

1.00

1.50

0.82

0.82

0.78

0.76

1.00

0.55

0.55

0.54

0.53

w

W

W

w

W

W

w W

W

n

n

0.50 0 0

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0.45

2. Determine Height H, and foundation foot length W. 0,15

0,20

0,25

0,30

0,35

0,40

0.55

0.60

Quick graphic determination of foundation foot width and the average thickness of cantilevered walls. The data is used for the initial rough work. A civil engineer must calculate the values ​​before implementation.

1. Select a type: I, II, III, or IV.

¸ ¸

0.50

0,45

0,50

0,55

0,60

3. Then determine the thickness of the wall n on the same line over the curve.

Landscape Stabilization 127

n

n

Gravity walls.

Gabions Gabbia is the Italian word for “cage,” and gabions are basically similar to wire cages. They have been used for over a century to build gravity walls. They are stable, durable, resistant to settling, and permeable. The relatively thin wire makes quick construction adjustments possible. Similar to dry stone walls, the loose stone filling allows small organisms and plants to establish themselves within the gabion walls. The diversity of possible fill materials and even the integration of lighting are some of the reasons why gabions have found a place in garden design as an esthetically pleasing retaining wall option. Currently, gabions can be used for retaining walls up to a height of three meters. Due to structural considerations, large support constructions are unadvisable. Gabion retaining walls are engineered as normal gravity walls. The principle is simple: the higher the wall, the wider the base. Using enormous amounts of stone is only economically feasible if the stone can be found on site or nearby. As this is most often not the case, the height of a gabion wall is restricted. Gabion walls require foundations, ideally made from a gravel and sand aggregate mixture. As with all retaining structures, attention must be paid to drainage. Since gabions are permeable, it is sufficient to separate the gabions from the soil using a filter membrane. Geomembranes tend to become blocked, so it is important to use a filter membrane! Conventional drainage using a combination of a drainage layer (such as a drainage mat) with a permeable drainage pipe is also an option.

128

Construction concept of a gabion retaining wall by SYTEC.

Gabions in a garden.

Today, gabion baskets are made of rectangular wire meshing, spot-welded and assembled with clips or spirals. Intermediate walls and spacer elements stiffen the baskets. The meshing, walls, and spacers are all made of galvanized aluminum wire. Ideally, gabions should be filled by hand. However, different mesh sizes and wire strengths allow mechanical filling, as well as filling with different materials (for example, the extruded crushed glass product Misapor). The esthetic of the wall will vary correspondingly. Fine mesh sizes or double mesh systems emphasize the metal mesh more than larger meshes. As a basic rule, the fill material must match the mesh size. Ready-filled gabions have also become available recently. The ready-made gabion baskets come straight from the quarry, where they are filled right on vibrator plates. They are made using six- to eight-millimeter wire, often combined with flat-bar steel, and can therefore be made very large, and lifted and transported once filled. This new generation of gabions makes sense for large sites with simple geometries. Adjustment on site is not possible. When there is poor access to a site, or complex layout geometries need to be built, unfilled gabions are the better option. Peter Geitz, landscape architect and bioengineering specialist, writes: “Gabions should contain both soil and vegetation so that the empty spaces between the rocks can support growth, increasing both their aesthetic and ecological value. We plant layers of shrubs, hedges or shrubs and hedges, as was once common practice, between the layers of gabions. The gabions are thus grown through with roots and hold together better long-term, even if the wire should rust through.” (Peter Geitz, Geitz & Partner GbR, mail October 16, 2007).

Landscape Stabilization 129

A stone block wall acts as the embankment retaining element adjacent to a garage entrance.

Planted retention elements in a new housing development. Poor design is the price of maximum use.

Stone Block Walls Stone block walls are walls made from big, flat-surfaced blocks. For large heights they are combined with nailing (cuts) and reinforcement (fills). Stone block walls require gravel and sand aggregate foundations. Pre-cast Element Retaining Walls Planted pre-cast retaining elements belong to the gravity wall group and are only suitable for heights of up to four meters because of their narrow width. Pre-cast retaining wall systems are found in almost every construction material catalog. However, their appearance is often unappealing. Natural Stone Retaining Walls Natural stone walls with concrete backing are most often found in mountainous regions. The backing concrete is poured as the front stone cladding is built up. The wall should be composed of at least 30 percent connector stones (24 centimeters thick and interlocking at least ten centimeters into the concrete). The reinforcement should be calculated by a structural engineer. Walls up to one meter high can be built as dry stone walls.

130

Concrete reinforced natural stone wall.

Dry stone wall.

A natural stone wall at Frank Lloyd Wright’s Fallingwater in Pennsylvania, U.S.A.

Landscape Stabilization 131

Grading Roads and Parking Spaces

Grading and Roads The lines that roads draw through our landscape greatly affect how the landscape looks as a whole. When considering different alternatives in context with environmental impact analyses, landscape architects assess and compare the impact of a road on the landscape. They are also involved with landscape conservation support plans in the road planning itself. Landscape architects also plan the access roads that lead to hotels and clubhouses, and go through parks. All these activities require basic knowledge of road development, which can readily be transferred to the planning of simple pathways. The following information about the required basic technical knowledge refers to roads with very slow traffic: “slow roads.” However, the relevant road construction standards are more specific about road requirements. Technical Basics — The minimum lane width for a slow road is three meters. — The longitudinal profile (slope) of a road should coincide logically with the horizontal lines. If a change in direction is required, it is planned before and not after the crest of a hill. — Cutting grades should not be done because of drainage and snowdrifts. — A position slightly more elevated than the surrounding terrain is recommended in lowland areas (better drainage, less ground fog, snowdrifts), and is given a side-strip and an embankment (1:4 to 1:5). — The lines of a road are always defined by the axis in the site plan, a longitudinal profile (gradient), and a cross-section. — Very simple curve geometry on the axis of straight line—circle—straight line is applied for slow traffic conditions. The transition from the straight line to the circle

Roads and Parking Spaces 133

A right-angle access to the contour lines is the quickest way to get from point A to point B, but could require stairs or trenches for certain gradients.

A pathway or road running almost parallel to the contour lines would take longer to travel along than a right angle from point A to point B, but does not require stairs or major changes to the terrain.

extends until the straight line touches the circle. Here the straight line lies perpendicular to the radius at the contact point. A clothoid curve principle is used for roads with heavy traffic. This provides a continuous transition between the circle and the straight line. Clothoid curves are used to ease vehicle steering. — Lines of a road on a map: fifty meters is the minimum radius of curves at a speed of 30 km/h. — Lines of a road in longitudinal sections: the maximum longitudinal slope at a speed of 30 km/h is 12% and the minimum 0.5%; the radii of the curves of peaks/troughs is 2100/1200 meters. — Lines in the cross section: – in straight lines—min. 2.5%; max. 3% cross slope. – in curves—min. 2.5%; max. 7% cross slope, inward slope.

134

A road axis with simple curve geometry in the plan.

Section of the road axis with the curve geometry of straight line–circle–straight line.

Roads and Parking Spaces 135

The line of the road in the longitudinal profile with a sag (dip) and two crests.

Section of the road crest.

Section of the road sag (dip).

136

Cross section of the road with connection to the existing terrain.

The new road incorporated in the gradient diagram.

Civil 3D terrain model of the road.

Roads and Parking Spaces 137

The dirt track of a slope is indeed the fastest connection between bottom and top, but useless as a long-term solution for the site development.

A mountain pass in the Swiss Alps winds up a mountain. The Romans used it as a fortified road connecting northern and southern Europe.

Cross section of a Roman road. An early example of directing rainwater into trenches on the side of the road’s surface (see Eidenbenz 2001, p. 8). This design is still useful for road construction today.

138

Highlight Towers Munich, PWP Landscape Architecture.

Grading and Parking Spaces Parking has been around since time immemorial. Initially animals and carts were parked; today we park individual means of transportation such as trucks, cars, motorcycles, and bicycles. Although public transportation is becoming increasingly important, individual means of transport will continue to exist in the future. Multistory underground and above-ground parking lots accommodate vehicles in city centers, where the cost of land is high. Above-ground parking lots are the most cost-effective solution if enough space is available. While transportation planners focus mainly on functional aspects, the task of landscape architecture is to incorporate parking spaces into a creative context. However, this issue is sorely neglected, as demonstrated by the lack of literature. The layout, planting concept, surface coverings, and drainage of parking lots are more than worth a closer look, because such parking places for cars have the potential to become actual PARK places. Terms A parking lot is an uncovered parking area for vehicles and refers to the entire area, consisting of: — the parking spaces, with different parking field angles, — the road, with lateral parking areas, — the approach road (no parking spaces), — planted strips, and — planted islands.

Roads and Parking Spaces 139

German Post HQ, Bonn, PWP Landscape Architecture.

Arrangement and Dimensions Basically, there are three possible arrangements for parking spaces: vertical, diagonal, or longitudinal. The most efficient is the vertical arrangement. It occupies little space and can be accessed easily from both directions. However, it takes a bit longer to maneuver a vehicle into a vertical space than it does into a diagonal formation. If a parking lot is also a dead end, the driver of the vehicle should be able to see whether parking spaces are available before entering the lot. If there is no way to turn around, the spaces have to be arranged vertically, so that the width of the road itself allows for turning. In the United States, turning bays are built at the end of parking spaces if there is no other way to turn around. They make it easier to exit the parking area from the farthest spaces. The diagonal formation requires more space, in spite of the narrower width of lanes and parking spaces. However, this arrangement allows vehicles to be parked quickly and easily. The longitudinal formation is the least efficient, as it requires the most amount of space. It is used for loading and for parking on roadsides. Horizontal Layout In designing access roads to parking lots with a speed of 30 km/h, a simple tangent— curve—tangent central axis geometry is used. Transition curves are not applied, because the key factor for the horizontal radius in low-speed access roads is the stopping sight distance, and not the dynamics of vehicle movement, as is the case with roads that carry high-speed traffic. The minimum horizontal radius for those roads is twenty-five meters.

140

Parking lot layouts by HSR students.

Vertical Layout Parking lots and the surrounding grounds must be considered together. Lowering the elevation of a parking lot can improve sightlines and reduce the visibility of the site. The spaces and the pathways (including ramps) both need to be drained. Funneled slopes, pitched slopes, or one-sided slopes are possible methods. However, the slopes should never be more than five percent in the longitudinal and transverse direction. With steeper slopes, there is a risk of the vehicle rolling away, and of damage to the vehicle’s doors if they swing open. Unlike road construction, at the entrances to parking lots (30 km/h), there are no hillcrests or troughs that the vehicle could hit. This is because of the maximum of six percent slope. For optimum water drainage, roadways must be constructed with a one-sided or roof-shaped slope of two and a half to three percent. The following values apply if the vertical longitudinal slope is greater than six percent: Knoll: Rv min = 20m Trough: Rv = min 40m

Roads and Parking Spaces 141

Action of SWA Los Angeles to PARK(ING) DAY (www. parkingday.org).

Borders There are various ways to design the verge between the parking area and the planted area or the access road. Increased elevation at the verge protects trees from damage and root zones from compacting. If it is not possible to raise the verge elevation, tree protection systems are an effective, though costly, alternative. The elevation increase of the verge in the form of a curbstone should be no more than eight centimeters. Higher curbs can cause damage to vehicles. These are also called overlap strips. They must be taken into consideration in the construction of walls, plumbing, and planting. Sometimes parking lots have wheel stops. These are mostly precast, sometimes dyed concrete, which are fixed onto the surface covering and are meant to keep the vehicle within the parking field perimeter. These elements are not always recommended, since they may pose tripping hazards and act as dirt traps. They also impede snow removal. Planting Planting strips with trees should be part of every parking lot. Trees provide shade, contribute to increasing the air humidity, and add to the visual layout of parking spaces. Planted islands are larger planting strips with parking bays. They separate two-sided parking spaces and have T-shaped, square, or rounded heads at the ends. Sometimes a walkway is also integrated. A tall canopy tree needs a tree pit with an area of six square meters and a depth of at least 1.20 meters. Therefore, the minimum width of a planting strip or planting island, measured from inner edge to inner edge of the curb, must be two and a half meters, and a width of three meters is preferred. It is advisable to consult the literature, and to select tree species recommended by local park departments for planting along roads. The same applies to the underplanting of trees. Trimmed hedges, in combination with trees or as an independent planting concept with a maximum height of eighty centimeters (it is essential to consider visibility in the aisles, exits, and so on), offer an additional means of planting parking lots.

142

Handicapped Parking A disabled parking space should be at least twelve feet wide, should not have a slope, and should be clearly marked on the ground. Cobblestone and grass pavers are unsuitable. The parking space could be combined with the pedestrian area if this is not separated from the parking space by a curb. Wheelchair accessibility is an essential consideration. Projecting walls, columns, or pipes should not impede or obstruct the path. It is advisable to provide covering for outdoor handicapped parking. A covered link to a building entrance is a great relief for wheelchair users, and is essential in snowy regions. In the case of public buildings and facilities, at least one disabled parking space must be located near a wheelchair-accessible entrance (Handbuch Hindernisfreies Bauen, p.  21, Swiss Paraplegic Foundation, 2005). Parking Lots in Overview: Tables, Calculation Basics, Layout The following pages contain tables and drawings on the subject of parking lots. The information comes from standards and publications, some of which are no longer available. They have been compiled by the author based on his many years of teaching experience. The same questions arose again and again during his supervision of student work. The information has been condensed and put into graphic form in order to make it easier to read.

The data is taken from the Swiss standard SN 640 291a (VSS Swiss Association of Road and Transport Professionals). The standard distinguishes between the following comfort levels: A – passenger cars near residential and commercial buildings, B – passenger cars near public institutions, hotels, shopping centers, and so on, and C – delivery vans.

Minimum lane widths for diagonal and vertical parking spaces in relation to comfort levels Minimum lane widths for diagonal and vertical parking spaces in relation to comfort levels Type of traffic Type of traffic

Lane width Lane width L[m] L[m]

Turning loop width Turning loop width Fk [m] Fk [m]

One-way traffic One-way traffic

3.00 3.00

3.40 3.40

Two-way traffic Two-way traffic

5.00 5.00

5.40 5.40

One-way traffic One-way traffic

3.30 3.30

3.70 3.70

Two-way traffic Two-way traffic

5.60 5.60

6.00 6.00

Comfort level Comfort level A, B A, B

C C

Minimum dimensions of vertical parking spaces for small cars in relation to comfort levels Minimum dimensions of vertical parking spaces for small cars in relation to comfort levels Comfort level Comfort level A A B B

Parking Parking space length space length L [m] L [m] 3.70 3.70 4.00 4.00

Edge parking space length Edge parking space length Lr1 [m] Lr1 [m] 2.80 2.80 2.80 2.80

L2r [m] L2r [m] 4.30 4.30 4.60 4.60

Parking Parking space width space width w [m] w [m] 1.80 1.80 1.80 1.80

Overhang Overhang strip width strip width T [m] T [m] 0.20 0.20 0.20 0.20

Lane width Lane width L [m] L [m] 3.00 3.00 3.00 3.00

Roads and Parking Spaces 143

Minimum dimensions of diagonal and vertical parking spaces in relation to comfort levels Comfort level

Parking space angle

Comfort level A b [m] 2.35 2.50 2.65 2.80 2.45 2.60 2.75 2.70 2.90

Comfort level B b [m] 2.50 2.65 2.80

45° 30°

90°

75°

A, B

Parking space width

60°

L [m]

75° C 60°

L2 [m]

Overhang strip width

Lane width

Area per parking space

U [m]

F [m]

[m2]

6.50 5.75 4.00 3.00 5.00 4.20 3.00 3.50 3.00

19.4 19.7 18.6 18.2 19.1 19.2 18.7 18.9 19.6

5.00

10.00

0.50

2.60 2.75

5.30

9.50

0.50

2.90

5.25

9.05

0.45

3.30

3.55

4.90

8.60

0.35

3.00

21.1

4.70

5.00

4.10

8.30

0.25

3.00

26.3

7.80 7.00 5.40 6.20 5.20 3.30 4.40 3.50 3.30

26.3 27.2 26.7 25.9 26.4 25.3 25.8 26.5 28.2

2.60 2.80 3.00 2.70 2.90 3.10 3.00 3.25 3.50

90°

6.20

12.00

0.70

6.50

11.50

0.70

6.40

11.00

0.60

45°

3.70

5.90

10.60

0.50

3.30

27.9

30°

5.20

5.00

10.25

0.35

3.30

34.6

Fk b

W

144

Parking space length

U

U

L-U

L-U

F

F

L2

Fk

b

L2

F

F

L

L W

Geometry in diagonal and vertical parking spaces: b – width of a parking space. F – width of the lane. Fk – width of the lane in hairpin bends. L – length of a parking field. L2 – length of two contiguous parking fields. U – width of the overhang strip. W – wall.

1

2

3

4

The tighter the parking angle, the more ground area is needed in a car park (see table previous page): 1. 90 ° 2. 60 ° 3. 45 ° 4. 0 °.

Parking space requirements for motorcycles.

Parking space requirements for bicycles.

Parking space dimensions and lane widths in bicycle parking facilities.

Roads and Parking Spaces 145

1 Without planted strips.

2 With planted strips.

3 The recess solves the problem of sight obstruction caused by the parked cars.

4 Doubled capacity due to parking pallets.

5 Installation on steeper paved gradients and slopes.

Planted strips and variants of planted islands and parking bays.

146

Overhang strip.

Parking space edge formations (Source: Simon Bell, 2008: Design for Outdoor Recreation, Taylor & Francis, Abingdon).

Parking surface coverings:

Gravel turf.

Grass pavers.

Pavement.

Asphalt.

Roads and Parking Spaces 147

Arconda Tree Protection System for streets and roads.

Structure of Arconda Tree Protection System (Tschümperlin AG):

5

5 The galvanized, flat-bar steel tree trunk protection system protects trees from vehicle collision. They are also available with stove enamel finishes with RAL.

4

4 Three-piece, cast inner ring for mounting on the cast cover. The inner ring may be removed at a later date if the tree outgrows it.

3

3 Cantilevered, four-part cast cover with a non-braked wheel load of 50 kN. The cast cover is placed loosely into the steel frame and then bolted together. 2 Two-piece, galvanized steel frame, which is set in a mortar bed on the planted pit extension in the corresponding gradient and bolted together. 1 Concrete foundation with a planted pit extension to provide more space for roots. The planted pit extension is based on four point bases.

148

2

1

3.50

6.00

5.00

2.50

5.00

R2.00

3.30 W2

R2.00

2 2

4

3.00

R2.00

W1

1

Recommendations for constructing parking lot entrances (source: Forschungsgesellschaft für Strassen- und Verkehrswesen, Empfehlungen für die Anlage von Erschliessungsstrassen (Recommendations for Constructing Access Roads), Cologne, 1995, p. 59). W1 – width of road lanes. W2 – width of access roads.

3

4

5

R [m]

R [m]

R [m]

6

8

10

12

2

4

6

8

10

12

2

4

6

8

10

12

2.75

3.50

2.50

2.20

2.00

1.90

1.90

4.80

3.20

2.80

2.60

2.40

2.30

8.80

6.30

4.30

3.50

3.20

3.00

3.00

3.30

2.40

2.20

2.00

1.90

1.90

4.40

3.20

2.80

2.60

2.40

2.30

7.60

5.30

3.90

3.40

3.10

3.00

3.25

3.10

2.30

2.10

2.00

1.90

1.80

4.10

3.10

2.70

2.50

2.40

2.30

6.90

4.70

3.70

3.40

3.10

2.90

3.50

3.00

2.30

2.10

2.00

1.90

1.80

3.90

3.00

2.70

2.50

2.40

2.30

6.30

4.40

3.60

3.30

3.00

2.90

3.75

2.80

2.20

2.00

1.90

1.90

1.80

3.70

2.90

2.60

2.50

2.30

2.30

5.90

4.20

3.50

3.20

3.00

2.90

4.00

2.80

2.20

2.00

1.90

1.90

1.80

3.60

2.90

2.60

2.40

2.30

2.20

5.70

4.20

3.40

3.20

3.00

2.90

4.50

2.60

2.20

2.00

1.90

1.90

1.80

3.40

2.80

2.50

2.40

2.30

2.20

5.00

3.90

3.30

3.10

2.90

2.80

4.75

2.50

2.10

2.00

1.90

1.80

1.80

3.30

2.70

2.50

2.40

2.30

2.20

4.80

3.80

3.30

3.10

2.90

2.80

5.50

2.30

2.00

1.90

1.90

1.80

1.80

3.00

2.60

2.40

2.30

2.30

2.20

4.40

3.60

3.20

3.00

2.80

2.80

6.50

2.20

2.00

1.90

1.80

1.80

1.80

2.80

2.50

2.30

2.30

2.20

2.20

4.00

3.40

3.00

2.90

2.80

2.70

Recommendations for constructing parking lot entrances (source: Forschungsgesellschaft für Strassen- und Verkehrswesen, Empfehlungen für die Anlage von Erschliessungsstrassen (Recommendations for Constructing Access Roads), Cologne, 1995, p. 59). 1 Road lane. 2 Arc radius. 3 Car access. 4 Delivery van access. 5 Refuse vehicle access.

Roads and Parking Spaces 149

22.00 22.00

22.00

18.00 18.00

6.50

6.50

3.40 8.60 6.00 3.40 6.00 1.00 1.00 1.00 1.00

R 12.00 R 12.00

7.60

6

7.60 6.00 6.00 0.90 0.90 1.00 1.00 1.00 1.00

7.606.00 6.00 0.90 0.90 1.00 1.00 1.00 1.00

14.35 9.00 25.00 2.00 2.00 23.30 23.30

23.30

R 12.00 R 12.00

23.30

R 6.50

7.60

25.00

14.35 2.00

5.00 1.00 11.80

5.00 1.00 2.00

11.80 22.40 6.50

R 6.50

14.35 0.84

25.00 2.00

R 13.00 R 13.00 8.60 3.40 3.40 6.00 6.00 1.00 1.001.00 1.00

Examples of turning areas (turning loops and turning circles). They are often used at entrances to parking lots:

2.00

2.00

15.50 2.00

1.25

5.00 1.00

2.00 5.00 1.00

2.00 15.50 15.50 2.00

2.0015.50

0.84

3.00 6.00 1.753.00 1.75

R 6.50R 6.50

22.40 11.80

22.40

2.00

9.00

12.00

2.00

R 6.50 R 13.00 R 13.00

8.60

150

3.00 6.00 1.75 3.00 1.75 1.25 1.25

1.25

4

2.00

R 6.50R 6.50

8.60

5

6.00

2.00

22.40

7.65 9.75 9.75

7.65

9.75

19.00 2.00

2.00

5.00 1.00

2.00 19.00

R 6.50

9.75

19.00 19.00

6.00

2.20 1.80

2.00

7.65

5.00 1.00 7.65

5.00 1.00

2.00

5.00 1.00

2.00

2.00

R 15.00 R 15.00

11.80 6.50

4.00 6.00 2.20 4.00 1.80

3

12.00

4.00 2.20 2.20 1.80 1.80

2.00

6.00

6.00 4.00

0.84

2.40

R 15.00 R 15.00

9.00

R 9.00

14.35 25.00 9.00 0.84

17.60

17.60 32.00 12.00 2.40 32.00 2.40 17.60 12.00 2.40 32.00 32.00

00 6.

00 6.

6.00

00 6.

00 1.

R 20.00 R 20.00

18.00

00 1.

R 9.00R 9.00

R 9.00

R 20.00 R 20.00

18.00

00 6.

00 7.

00 7.

R 11.00 R 11.00

00 1.

00 1.

00 1.

00 1.

17.60

00 7.

00 7.

R 11.00 R 11.00

2

22.00

00 1.

00 1.

1

1 Turning loops, symmetrical, for a ten-meter-long truck. 2 Turning loops, symmetrical, for an eight-meter-long truck. 3 Turning circle, left, for a tenmeter-long truck. 4 Turning circle, left, for an eight-meter-long truck. 5 Turning circle, symmetrical, for a ten-meter-long truck. 6 Turning circle, symmetrical, for an eight-meter-long truck.

8

9 4.00

4.0 0

4.00

1.00

7 Loop in a parking lot for an eight- to ten-meter-long truck.

8.00

1.00

1.00

10.00

10.00

R2.00

R2.00

Examples of turning areas in a parking lot and for two mini traffic circles:

8.00

1.00

4.0 0

7

8 Mini traffic circle with traversable central island: radius of eight to ten meters.

9 Mini traffic circle with a partially traversable center island: radius of ten to twelve meters.

Access road and parking lot layout: ideas in a landscape context (Source: Simon Bell, 2008: Design for Outdoor Recreation, Taylor & Francis, Abingdon).

Roads and Parking Spaces 151

Grading and Stormwater Management Michael Fluss, Peter Petschek

Stormwater Management Basics Clean water is an essential and very precious asset. Precipitation replenishes the groundwater needed for drinking and watering vegetation. In order to keep groundwater free of the toxins and other contaminants acquired during precipitation and infiltration, the complex subject of stormwater management should be given the attention and care it deserves. This chapter will focus mainly on infiltration systems that can be created by grading; we will not be addressing the entire range of infiltration installations. The basic objectives of stormwater management are: — replenishing groundwater with clean rainwater, — optimizing infiltration by means of grading, and — optimizing the design of open space in order to slow drainage velocity by installing long drainage conduits through planted swales and basins (flood protection). Grading offers the most efficient solutions for on-site infiltration of stormwater: even something as simple as raising the level of paths and hardscape areas will create infiltration and retention areas in the green spaces that lie between. Runoff water from roofs should be channeled through gutters and swales into the natural water cycle by a downspout on the facade, rather than into the public sewer system through pipes embedded in concrete. Planted swales or pavement gutters, with elevations that can be determined by grading, can easily be linked to form a simple infiltration network. The landscape planner and stormwater expert, Michael Fluss, speaks of “communicating swales” in this context. Such a system is easier to maintain than pipes. In addition, the “communicating swales” system can save money. For instance, to relieve pressure on the public sewer system, many cities have lowered the wastewater charges for infiltration, in order to encourage people to stop channeling surface water into the sewage system. Moreover, local infiltration is not only easy on the wallet, but also on the ecosystem, because water flows directly back into the natural water cycle.

Stormwater Management 153

A park in Phoenix, Arizona, located between a parking lot and two very busy streets. The grading, implemented at little cost and effort, transformed the space from a traffic island into a park.

A shallow swale carries the runoff from the parking lot to a sunken hollow in the middle. Here the water can infiltrate on site and so save money.

For locally and ecologically viable wastewater disposal, the best solution is provided by a combination of green roofs, permeable surfaces, and surface infiltration. The ideal situation would be as follows. A green roof slows the drainage of rainwater. The water filtered by permeable surfaces is collected in a rainwater tank so it can be reused to irrigate the garden. Rainwater that accumulates on surfaces is channeled through surface infiltration directly into adjacent vegetation areas with lower elevations. To prevent waterlogging, the edges of path surfaces should be designed in a way that allows the water to be uniformly distributed over the entire lawn or planted surface. When surface infiltration rates can’t keep up with rainfall, the capacity can be increased by adding a swale-trench infiltration system. This entails replacing soil one to two meters below the swales with gravel, and installing a drainage pipe (trench). Then the backwater volume in the gravel and the pipe supplements the surface storage. When space is tight and for safety reasons (for example ensuring the safety of children if water levels are above twenty centimeters), subsurface system components can be used to retain water in storage elements and allow it to drain slowly. These innovative stormwater retention systems are increasing in popularity. Modular retention systems are used wherever pools, ponds, and wells are not suitable for reasons of space, design, or safety. The hollow bodies, mostly made of plastic, are now able to withstand the pressure of three to four meters of soil covering. In order to verify the required compressive strength, the supplier must be able to provide test results from independent and reliable institutions.

154

1 4 6

2

3

5

Natural rainwater management: 1 Infiltration. 2 Retention. 3 Reduction of rainwater runoff into sewage system. 4 Surface collection. 5 Rainwater use. 6 Delayed drainage.

The multi-dimensional, permeable containers have a storage capacity of ninety-five percent, are very variable, and can be “hidden” underground. Due to the technical development of plastics and manufacturing processes, stormwater use and infiltration systems offer increasingly favorable price-performance ratios. Consequently, stormwater management is now possible in areas where it was rejected due to cost in the past. Stormwater contaminated with pollutants is a problem. Toxic contamination results from precipitation encountering locally polluted air and surfaces, such as traces of oil and tire wear in parking lots and on streets. The quality of groundwater is threatened when this water infiltrates the soil directly: it needs to percolate through a live, filtering layer of topsoil. If no green area is available, filter shafts such as Rehau Rausikko Hydroclean provide a good alternative to a live topsoil layer. In a rainwater filter shaft, the rainwater inflow is cleansed of coarse and fine sediments and dissolved contaminants such as metals. Then the purified rainwater is channeled into storage blocks. Swale-shaped seeping basins made of polypropylene (PP) with a filter substrate can also be used successfully to purify stormwater. Such filter shafts are most often used in construction projects where green spaces are not available, and, if properly maintained, guarantee a tested and consistently reliable purification of stormwater. A maintenance contract ensures that the filter substrate containing contaminants is disposed of in accordance with regulations.

Stormwater Management 155

A grass swale with subsurface retention elements.

Swale with natural planting.

A swale with a garden-like planting scheme. The term “rain garden” is used in Australia and the U.S.A. for this concept.

156

8 5

6

1

3

7

4

2

4 1

3

2

Infiltration basin and infiltration swale (basis: VSA Swiss Water Association Stormwater Management Guidelines): 1 Subbase with sufficient drainage capability. 2 Ground water levels. 3 Topsoil > 20cm. 4 Subsoil > 30cm. 5 Inflow. 6 Maximum retention level. 7 Riprap and paving. 8 Level drain.

Stormwater Management 157

Rainwater runs from a downspout into an open swale.

A rectangular section drainage channel with its own grade carries any uninfiltrated rainwater to a swale area.

D-Rainclean–the PP filtration channel with substrate is used to purify and infiltrate polluted rainfall runoff from roads, parking lots, and copper or zinc roofs (www.funkegruppe.de).

158

Unlike pipes, open channels can always be inspected.

A permeable surface should have a slope of at least 2.5 percent.

Paving manufacturers recommend a minimum slope of 3 percent, even when permeable paving is used. The underlying layers (base layer, subbase, etc.) should have the same gradient as the paving surface.

Stormwater Management 159

A retention system built several meters deep into the earth. However, health and safety requirements were not met during construction. Regulations stipulate that deep excavation walls must be protected with temporary sheet piling.

Storage blocks made ​​of PE (polyethylene) with a storage capacity of 95 percent.

Workflow and Calculations for Stormwater Management It often happens that the project budget is not sufficient to finance an additional specialist such as a hydrogeologist. Therefore, in small projects, landscape architects must be able to correctly assess and manage the retention and infiltration of rainwater. The author has developed a stormwater management system in collaboration with the landscape architect Michael Fluss, based on Swiss standards and guidelines. The main goal of the workflow that follows is to support the planning process for stormwater drainage, infiltration, and retention by simplifying the process as much as possible. Although this stormwater management workflow is based on Swiss standards, it can be applied worldwide. In the e-book edition of this book, all the calculations can be done interactively. 1. Optimization The following questions should be taken into consideration before planning a drainage system: — Can the elevation of paths and hardscapes be raised above the surrounding green area? (This allows small retention areas in the green spaces.) — What would the longest possible rainwater discharge conduit over the open space look like? — Is it possible to create shallow infiltration swales by grading? (Swales designed with small trees, shrubs, and stone are almost invisible and yet optically appealing.) — Can drainage plates, open-jointed slabs, turfstone, or rock-filled woven wire mats be used? — Can the roof be planted, or even fitted with a water retention surface? — Can a rainwater utilization system with a rainwater tank be installed?

160

— Can stormwater from the downspout be channeled through gullies or shallow, planted ditches? Gullies and ditches are easier to maintain than pipes. 2. Water infiltration is not possible in the following cases: — in groundwater protection zones, — in earth fills, — in contaminated soil, — where the groundwater levels are high. (The distance between the bottom of the seepage basin and the highest groundwater level under one meter.) — If the soil is not capable of seepage (silt and clay), — if gradient stability is insufficient, — when water in gradient areas poses a risk to areas downstream, — near leaky basement walls. The following soil types are unsuitable: — brickearth with fine sand particles, — brickearth, — clay, and — soils contaminated with pollutants.

8

2 1 7 6

4

Stormwater management project in a restricted area: 1 Subsurface infiltration system by Rehau. 2 Vegetated filtration channel. 3 Green roof. 4 Permeable surface. 5 Pavement channel. 6 Box gutter. 7 Downspout. 8 Emergency overflow drains.

5

7 3

2

7 4 5

2 Stormwater Management 161

If the above points do not apply, permission is generally not required for infiltration of small amounts of water from roofs, garages, and other subsidiary buildings where no specific facilities are installed, and where the top layer of the soil is not damaged (surface infiltration). The project requires that no third party (such as a neighbor) is affected, and that other relevant laws and regulations (such as building laws and neighborhood laws) are observed. Larger infiltration systems are structural systems and therefore generally require authorization. If on-site infiltration is not possible, the stormwater must be channeled into the sewage system or other receiving waters. Suitable soils for infiltration are: — humus-rich topsoil, — sandy and gravelly soils, — coarse, medium, and fine sand, — sand with fine sediment, and — sandy fine sediments. 3. Calculating Stormwater Runoff The formula used to calculate the stormwater runoff is: QR = A * r * C * SF [l/s] QR – stormwater runoff per partial or total surface in l/s, A – effective irrigated area, horizontal projection, in square meters, r – rainfall yield factor l/s, m2. Areas with average precipitation are to be calculated with a value of r = 0.03 l/s m2. Depending on the region and the possible consequences of overloading the drainage system, a rainfall intensity of up to 50 percent higher is to be calculated. C – runoff coefficient (dimensionless). Accounts for the properties and condition of the irrigated area and the resulting discharge delay.

162

Concrete and asphalt surfaces, waterbound surfaces incapable of drainage: C = 1.0, effective infiltration areas: C = 0.6, sloped and flat roofs: C = 1.0, extensive green roofs: 2–4 cm, 4–6 cm, 6–10 cm, 10–15 cm: C = 0.7, 0.6, 0.5, 0.4, intensive green roofs: 15–25 cm, 25–50 cm, over 50 cm: C = 0.3, 0.2, 0.1, SF – Safety factor (dimensionless). If water penetration into buildings can lead to high losses, the rainfall yield factor r is multiplied by a safety factor SF: 1.0 = no additional security (that is, no building), 1.5 = water causes more damage (such as shopping centers, factories), 2.0 = exceptional protection required (hospitals, museums, etc.). 4. Sizing Debris Traps, Box Gutters, Manholes, and Pipelines Debris traps gather and confine sediments and floating debris in rainwater. They also serve as a selective inlet and an odor trap. The debris must remain in the separation chamber for a minimum of thirty seconds. The debris traps in the list below fulfill this requirement for each inflow. Box gutters with or without internal gradients are linear stormwater collectors that must also be connected to a debris trap. With rainwater pipes, manholes must be installed at 40-meter intervals. Rainwater pipes are usually made from high-density polyethylene (PE-h) or polypropylene (PP). They should be installed in frost-free zones (usually eighty centimeters below ground) with a minimum gradient of one percent and a maximum of five percent. On gradients over five percent, a fall slope with two 45-degree bends should be provided and identified in the plan. Junctions of additional lines (splitters) are possible only at an angle of 45 degrees. The pipeline should be built herringbone-shaped, meaning that the stormwater is conducted from the farthest chamber through the main line into the secondary lines. All information on sizing, if not stated otherwise, is based on the Swiss standard SN 592 000 (as of 2012) of the VSA Swiss Water Association.

Stormwater Management 163

Debris trap.

≥ 0.1

2 3

7

5

4

1 Inflow grate. 2 Shaft depth. 3 Separation chamber. 4 Mud retention chamber. 5 Elbow pipe. 6 Diameter. 7 Usable depth.

0.05

1

6

1

Establishing the dimensions of a debris trap. The numbers refer to the chart above.

164

2 l/s

3 m2

4 m

5 ø in m

3.3 4.7 6.3 8.3 13.2 20.5 29.5 52.3 81.8 117.8

0.20 0.28 0.38 0.50 0.79 1.23 1.77 3.14 4.91 7.07

1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0

0.50 0.60 0.70 0.80 1.00 1.25 1.50 2.00 2.50 3.00

Galvanized steel box gutter, Leutschenbach Park, Zurich. Special design, Dipol Landschaftsarchitekten.

1

Establishing the dimensions of a debris trap for use in subsurface infiltration systems: 1 Debris trap. 2 Inflow. 3 Separation surface. 4 Usable depth from the bottom edge. 5 Applicable shaft.

2 l/s 1.4 1.9 2.5 4.0 6.2 8.9 15.7 24.6 35.4

3 m2 0.28 0.38 0.50 0.79 1.23 1.77 3.14 4.91 7.07

4 m 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1

5 ø in m 0.60 0.70 0.80 1.00 1.25 1.50 2.00 2.50 3.00

Box gutters Regarding the stormwater runoff ratio (QR): gutter length can be gauged roughly to determine whether a 100-millimeter-wide box gutter can handle stormwater. There is no problem with ratios less than or equal to 0.5, but values a​​ bove 0.5 are considered critical. Calculation example: One hundred square meters of asphalt surface is drained using a 100-millimeter-wide gutter. The channel line has a length of five to ten meters. 100 m2 * 0.03 l/s m2 * 1 = 3 l/s (QR) For a channel length of ten meters: 3 l/s : 10 m = 0.3 For a channel length of five meters: 3 l/s : 5 m = 0.6 This data is purely for pre-dimensioning: For more detailed information you will need to contact the box gutter producers.

Stormwater Management 165

Manholes.

Drawing of a manhole, floor plan and section.

166

1

2

3

4

less 0.6 m

ø 0.8 m

ø 0.8 m

ø 0.8 m

0.6 to 1.5 m

ø 0.8 m

ø 0.8 m

ø 1.0 m

over 1.5 m

ø 1.0 m

ø 1.0 m

ø 1.0 m

1 Shaft depth. 2 One inflow. 3 Two inflows. 4 Three inflows. From 1.2-meter-deep shaft with manhole ancilla.

Pipe.

%

Ø

1.0 %

1.5 %

2.0 %

2.5 %

3.0 %

3.5 %

4.0 %

4.5 %

5.0 %

4.2 6.8 12.8 23.7 37.6 44.9 80.6

5.1 8.3 15.7 29.1 46.2 55.0 98.8

5.9 9.6 18.2 33.6 53.3 63.6 114.2

6.7 10.8 20.3 37.6 59.7 71.1 127.7

7.3 11.8 22.3 41.2 65.4 77.9 140.0

7.9 12.8 24.1 44.5 70.6 84.2 151.2

8.4 13.7 25.8 47.6 75.5 90.0 161.7

8.9 14.5 27.3 50.5 80.1 95.5 171.5

9.4 15.3 28.8 53.3 84.5 100.7 180.8

100 125 150 200 225 250 300

Pipe sizing with pipe gradient and pipe diameters.

Stormwater Management 167

60 475.24 474.44 473.44

m

0/

PE 1 % -h Ø (5 12 .7 474.05 l/s 5 )5 .80

m

(2

10 0

A3 - 150m2, C - 0.6, SF - 1

1 50

(2

PE -h .7 Ø l/s 10 )8 03 m %

50 475.10 474.30 473.30

12 5

/1

25

474.05

3P

12

5/

60 475.24 474.44 473.44

m

15 0

E 1 % -h Ø (5 12 .7 l/s 5 )5 .8 12 5

m

10

0m

/1

50

1

473.99 PE 5 % -h Ø (4 1 0 .5 l/s 0 )9 .2 0

PE 1 % -h Ø (3 10 l/s 0 )1 5.1 0

PE -h .7 Ø l/s 10 )8 03 m %

475.00 474.20 473.20

m

1

A3 - 150m2, C - 0.6, 50 SF - 1

Project example: 1 Debris traps specifying shaft diameter, lid height, outlet, base. 2 Manhole specifying shaft diameter/diameter of the cone, lid height, inlet, outlet. This manhole requires a boarding aid because the shaft depth is greater than 1.2 meters. 3 Pipes must always specify the following data: pipe type, diameter, gradient, l/s, pipe length. 4 Introduction to an infiltration swale.

A2 - 150m2, C - 1.0, SF - 1

A1 - 100m2, C - 1.0, SF - 1

PE 5 % -h Ø (4 10 .5 l/s 0 )9 .20

PE 1 % -h Ø (3 10 l/s 0 )1 5.1 0

475.00 474.20 473.20

473.99

PE 1 % -h Ø (1 15 0.2 0 l/s )1 1

.70

PE 1 % -h Ø (1 15 0.2 0 l/s )1

475.10 474.30 473.30

m

1.7

0m

80/60 475.90 473.87 473.32

200 1: 200

2

80/60 475.90 473.87 473.32

4

QR = A x r x C x SF A x rxx 1.0 C x SxF 1.0 = 3.00 l/s A1: QR = 100QRx= 0.03 A1: QR = 100 x 0.03 x 1.0 x 1.0 = 3.00 l/s 150Q x =0.03 x 1.0 x 1.0 = 4.50 l/s A2: QR =A2: 150 x 0.03 x 1.0 x 1.0 = 4.50 l/s R 150QRx =0.03 0.6x x0.61.0 l/s A3: QR =A3: 150 xx0.03 x 1.0==2.70 2.70 l/s

5. Infiltration Test to Determine the Specific Infiltration Rate (IRspec) The limiting factor is the rate of infiltration of the soil. These calculations are complicated because assessing absorption capacity depends on soil properties such as porosity, soil type, humus content, and so on, and on the water table and the current level of saturation. Some of these factors are either unknown or approximated. Consequently, the soil’s rate of infiltration can be taken into account only roughly when calculating dimensions. The most important parameter for sizing an infiltration system is the specific rate of infiltration of the natural soil layer (the B-horizon) beneath the topsoil (the A-horizon). A simple method was chosen to evaluate the infiltration situation, in order to quickly create a database.

168

Infiltration test to determine the specific infiltration rate, IRspec.

How to estimate the specific infiltration rate: 1. Lift the turf soil layer. 2. Make a cylindrical hole of about 40 centimeters in diameter (dba) and 40 centimeters deep (hba) in the B-horizon or infiltration base. 3. Cover the base with three inches of fine gravel to prevent colmation. 4. Measure the depth or the diameter. 5. Presoak the hole with 40 liters of water to saturate the soil. 6. Lay a board horizontally over the hole. 7. Fill the hole quickly with 40 liters of water (QW). 8. Measure the distance from the board to the water level (∆lWT). 9. Establish the time it takes to infiltrate (ts). 10. Calculate the specific drainage (or consult the software program). 11. Test and critically evaluate the IRspec comparing the calculated value with the tabular values. dba = seepage ditch diameter [cm] hba = seepage ditch depth [cm] ∆lWT = distance from board to the water table [cm] QW = water flow [l] IRspec = specific infiltration rate [l / s m2] ts = infiltration duration [s] IRspec =

QW ts

*

1

[(

dba 2

2

)

* π + dba * π *

hba – ∆lWT 2

]/

10,000

Note: It is possible to calculate the specific infiltration rate interactively in the enhanced e-book by entering the values. There is also a video on how to conduct the infiltration test.

Stormwater Management 169

Reference values IRspec: Coarse gravel > 100 l/min * m2 – very appropriate. Gravel (clean) > 20 l/min * m2 – very appropriate. Fine gravel, sand and silt content > 10 l / min * m2 – appropriate. Sand, silt and gravel content 5–10 l/min * m2 – appropriate. Gravel and sand, slight clay content 0.5–5 l/min * m2 – very appropriate to moderate. Humus 1–3 l/min * m2 – moderately appropriate. Loamy gravel, sand with clay content 0.5–2 l/min * m2 – moderately appropriate. Gritty clay < 0.5 l/min * m2 – not appropriate. Silt, clay < 0.1 l/min * m2 – not appropriate. 6. Sizing the Infiltration System The interactive calculator in the enhanced e-book aids in determining the required retained volume of an infiltration system. The result, however, should only serve to as a rough preliminary guide: Use the software program at your own risk. There is no liability for incorrect calculations. The following steps are performed: 1. Enter the specific rate of infiltration values of the soil ​​determined in the infiltration test # IRspec [l/min * m2] 2. Enter the previously determined stormwater runoff QR [l/s] 3. Calculate the planned storage capacity [VP] and the corresponding effective infiltration area [AS]. A variety of different forms of infiltration basins are available: free-form infiltration basins, a truncated-pyramid-shaped basin, subsurface rectangular hollow boxes such as the REHAU “Rausikko Box,” a simple gravel formation, and a half-barrel -shaped seepage system. Enter the length, width and retention level of the relevant infiltration system.

i i

i

[#] Input field in the enhanced e-book = Output field in the enhanced e-book =

170

o

Infiltration basins: free form

A1 H1

A2

A1 = maximum retention area A2 = base H1 = maximum retention height VP = planned storage capacity AS = effective infiltration area

i [m ] i [m ] i [m] o [m ] o [m ] 2 2

3 2

Formula for the planned storage capacity (calculated approximately) [m3]: VP ≈

( A1 + A2 ) * H1 2

Effective infiltration area (calculated approximately) [m2]: AS ≈ ( A1 – A2 ) * H1 * 0.5

Stormwater Management 171

Infiltration basins: truncated pyramid

W1 L1 H1

L2 W2

H1 = maximum retention height L1 = maximum retention length W1 = maximum retention width L2 = base length W2 = base width VP = planned storage capacity AS = effective infiltration area

i [m] i [m] i [m] i [m] i [m] o [m ] o [m ] 3 2

Formula for the planned storage capacity [m3] (Only half of the side panel surface is taken into account.) Vp =

H1 * ( L1 * W1 + 3

L1 * W1 * L2 * B2 + L2 * W2 )

Formula for the effective infiltration area [m2]: AS = L2 * W2 +

172

(

(L1 + L2 ) * 2

H12 +

((L 2– L )) 1

2

2

+

W1 + W2 2 * H1 + 2

2

( W –2 W ) 1

2

)

Gravel formations: rectangular

H1

L1

W1

H1 = maximum retention height L1 = base length W1 = base width VP = planned storage capacity AS = effective infiltration area

i [m] i [m] i [m] o [m ] o [m ] 3 2

Formula for the planned storage capacity [m3]: VP = W1 * L1 * H1 * 0.20 Formula for the effective infiltration area [m2]: AS = L1* W1 + L1 * H1 + W1 * H1

Stormwater Management 173

Rectangular hollow box such as RausikkoBox REHAU

H1

L1

W1

In general, the hollow rectangular boxes are installed in several layers and rows. The total expansion is used for the calculation. H1 = maximum retention height [m] L1 = base length [m] W1 = base width [m] VP = planned storage capacity [m3] AS = effective infiltration area [m2] 0.95 = porosity factor (“RausikkoBox,” depending on the pore volume of the filler ma- terial).

i i i o o

Formula for the planned storage capacity [m3]: VP = W1 * L1 * H1 * 0.95 Formula for the effective infiltration area [m2]: AS = L1 * W1 + L1 * H1 + W1 * H1

174

1 2 3

4 Possible applications of underground stormwater management systems: 1 Rainwater retention with large pipe storage and delayed discharge into surface water or stormwater channel. 2 Subsurface infiltration/retention with upstream debris trap or stormwater treatment, with topsoil passage through swale infiltration trough. 3 Subsurface drainage/retention with mechanical pretreatment using sedimentation. 4 Subsurface drainage/retention with chemical and physical treatment (replacement of topsoil passage).

The Rausikko HydroClean rainwater filter purifies unacceptable polluted stormwater from a surface of 500 to 1000 square meters, depending on the type and amount of contamination in the connected area.

Stormwater Management 175

Seepage tunnel (cylinder with circular segment cross section)

H1 L1

W1

H1 = maximum retention height (circle segment height) L1 = base length W1 = base width VP = planned storage capacity AS = effective infiltration area

i [m] i [m] i [m] o [m ] o [m ] 3 2

Formula for the planned storage capacity [m3]: Radius calculation [m] r=

W12 + 4 * H12 8 * H1

VP = r 2 * L1 * arccos

((

r – H1 r

)

– ( r – h)

2rH1 – H12 r2

Formula for the effective infiltration area [m2]: arctan AS =

176

1 ( 4H12 + W12 ) ( 2H W1 ) *

2H1

* L1 * 0.5

)

7. Calculating the Required Capacity After the planned storage capacity (VP) and the effective i​​ nfiltration area (AS) have been calculated based on the infiltration system dimensions, the required storage capacity (Vn) has to be determined. These values (​​ VP), (AS), (Vn) are automatically output by the enhanced e-book program. In general, the value of the intended storage capacity (Vp) will differ from the calculated necessary capacity (Vn). In order to equalize the two volumes, the dimensions of the selected infiltration basin must be modified iteratively until both values are ​​approximately congruent. The following calculation steps are necessary: rate of infiltration [l/s] AS = effective infiltration area [m2] IRspec = specific infiltration rate) [l/s * m2] QS = infiltration capacity [l/s] Qs= (AS * IRspec) / 60 Specific discharge rate [l/s]: QR = rain runoff QS = specific runoff [l/s]

o o

Qab = QR - Q The required storage capacity [m3]: tR = rainfall duration 10 [min] Vn = required storage capacity Vp = planned storage capacity

o [m ] o [m ] 3 3

Vn = ( QS * 60 * tR ) / 1000 Vp ≈ Vn (both values ​​have to be made congruent by adjusting the dimensions of the infiltration system.) For a precise calculation, the authors recommend the REHAU RAUSIKKO software that can be downloaded for free from the website: www.rehau.com.

Stormwater Management 177

landscapingSMART and Digital Terrain Modeling l a n d s c a p i n g S M A R T

data output: paper plane

data output: analog model – cnc, 3d printer

data output: 3D machine control system no data: project start

data model

data input: gis data, grid ascii , ascii point cloud

data modeling: digital terrain modeling , 3d modeling

data output: real time model – 3d pdf, Google Earth data modeling: cloud services

The workflow of landscapingSMART.

BIM stands for “Building Information Modeling” and was originally developed for building construction. Over time, BIM has become important in infrastructure projects and is gaining in importance for landscape architecture. The idea is based on using a shared data model through various project partners such as government agencies, planners, civil engineers, and construction companies. A shared BIM model makes it possible to detect errors as early as the planning phase rather than on the construction site. landscapingSMART is a term that the author derived from the BIM initiative buildingSMART (www.buildingsmart.org). It stands for the efficient creation and use of a digital data model in landscape architecture. Increasingly user-friendly survey instruments can be employed for precise height recordings and to support staking out work on digital grading projects. Meanwhile, every CAD program is able to use the recorded elevation points for a triangulation and create digital terrain models. The digital terrain model (DTM) plays a central role in landscapingSMART. Over time, the field of landscape architecture has been subdivided into different fields of practice: planners plan, landscape architecture companies build. With “smart landscaping,” both worlds are brought closer together again: the digital terrain model is then directly linked to 3D machine control. Road builders today are increasingly using 3D machine control systems. Even free-style landscaping work, which is typical of landscape architecture, can be executed with accuracy to the centimeter without the need for extensive

landscapingSMART and Digital Terrain Modeling 179

staking out. This depends, however, upon the planner delivering his or her plan, based on a digital elevation model of the existing terrain, as a triangulation to the contractor. The data is transferred on site via USB stick by the construction company’s technician, directly into the control box of the excavator or dozer—making any staking out work unnecessary. The machine reaches the desired height immediately, provided the terrain data are correct. The machine converts the data one to one on site. In this manner, any possible errors in calculation in the data are converted directly, meaning that responsibility shifts from the builder to the planner. The planning data in digital terrain models thus needs to be given very close attention. It is safe to assume that 3D machine control systems in combination with digital terrain models created by the planner will also play an increasing role in gardening and landscaping in the future. However, despite the rapid development in digital terrain modeling and machine control, analog models remain indispensable tools for the creative process. Initially popular only in engineering, computer-controlled machinery is now used in architecture and landscape architecture (CNC milling), and in 3D printing, for the production of analog models. Until now, it was very complicated to convert changes made to the analog model back into digital data. However, this converting of data is becoming increasingly important for providing the 3D machine control system with digital data. Software from the research fields of photogrammetry, image processing, and computer vision in the form of cloud services now provides simple, fast, and surprisingly accurate results. The digitized model can be easily reintegrated into the DTM. While the topic of plan graphs has always held a firm position in the digital world of landscape architects, and is very important for “selling” a project, the role of interactive presentation techniques will continue to grow: No one wants to be “sold” a project; they prefer to envision it themselves. 3D PDFs or Google Earth real-time models are very well suited to this. Room planner Peter Zeile writes in his Ph.D. thesis that, “The task at hand, and for more than just the planning disciplines, is not the programming itself, but the use of these services and the willingness to learn about and engage in new developments.” (Zeile, 2010, p. 118) In addition to constantly updating the technology and data, the combined use of different software, cloud services, and hardware—in other words, working with a “mashup”—will become an ever more important skill in the global information society. landscapingSMART gives this complex whole a frame. New developments will arise and some will disappear. Digital terrain modeling, as a core element of landscapingSMART, will gain increasing importance in the office and on site.

180

Detail of the cadastral plan of the town of Rapperswil-Jona.

Data Bases and Data Collection Property boundaries, buildings, and uses are officially specified in cadastral plans and managed in a GIS system. The vector data are always present in a nationally uniform coordinate system with high numerical values. For one’s own site recordings, these plans allow one to quickly locate the local, permanently embedded brass bolts with their respective reference heights. Additional elevation data are provided by the land surveying offices in the form of ASCII point clusters. ASCII stands for “American Standard Code for Information Interchange” and contains a maximum of 256 symbols. A cluster of ASCII points on a single line always contains information regarding point number, easting, northing, z-value, and description. The data set can be opened with a simple text editor. Architects like to shift the cadastral data to the zero-point-zero (0.0) location of the CAD system, and then work with smaller numerical values. They also rotate the digital plans because of the layout. But if there are no established reference points, the positional reference may be lost in the national coordinate system. Working with national coordinates has a number of essential advantages over running a project using shifted plans. Therefore, we strongly discourage managing a landscape architectural project outside the national coordinate system. The reasons are below. — When using the national coordinate system, all data from architects, engineers, and technical engineers are at the same location. Reconciliation errors that might occur during the job can be recognized more easily. — Elevations for grading, axes of walls, stairs and pathways, and even the locations of trees, are all clearly defined by national coordinates. The respective easting and northing ​​can also be used to stake the site.

landscapingSMART and Digital Terrain Modeling 181

Cadastral surveying benchmarks.

An ASCII Grid matrix in a text editor, where the numerical values are in elevations per pixel.

An ASCII Grid terrain model in Global Mapper, based on an ASCII Grid matrix.

182

The same ASCII point clusters in Civil 3D.

ASCII point clusters in the text editor.

Caution should be used when speaking to surveyors about x and y values. CAD programs work with the Cartesian coordinate system. The horizontal axis is referred to as either the abscissa, the x–axis, or the right axis. The vertical axis is called the ordinate, the y-axis, or the vertical axis. In surveying work, easting and northing values define the positions of elements. However, here, the letter y represents easting, and x represents northing. For large projects, elevation data originate from overflights or laser scans. The term LIDAR data is occasionally used in connection with the laser scanning method. LIDAR stands for “light detection and ranging.” The responsible GIS office or private providers deliver these often-large amounts of data in the form of raster files. The elevations are represented in the form of grid cell elements. These “picture cell elements” (PIXELs) are uniform in size and arranged in a matrix. Every computer user is familiar with pixels from typical image editing programs. When elevation data is displayed in a grid format, each pixel has an additional value attribute for the terrain height. The data format is called ASCII Grid. It is also occasionally referred to as DEM (Digital Elevation Model). Professional CAD DTM programs can read this data. When this is not available, a lowcost program such as Global Mapper (globalmapper.com) can be used to convert grid elevation vector data into elevations.

landscapingSMART and Digital Terrain Modeling 183

Engraving by Thomas Medland: Humphry Repton’s flyer.

Small-Scale Data Collection and Staking Out Work Even before the mechanization of building construction, surveyor’s levels were standard equipment in garden design and landscape architecture. In 1788, the renowned English landscape gardener, Humphry Repton, advertised terrain modeling and surveying with business flyers. Repton printed 1000 of these, which show him at a construction site in front of a construction surveyor’s level, instructing his employees. Behind Repton, an exhausted employee holds the leveling rod. The engraving beautifully shows how surveying equipment was the first forerunner of mechanization in garden design and landscape architecture, long before the introduction of small excavators and milling. A surveyor’s level measures differences in elevation. A theodolite is an angle measuring device. A tachymeter is a further development of the theodolite and measures both angles and distances. The terms ταχυζ (tachys) und μετρον (metron) are Greek in origin, and mean “fast” and “measure.” As the word combination expresses, the tachymeter is for rapid measurements, and is available as a one-man or two-man system. Uncorrected data from a Global Navigation Satellite System (GNSS) have been used for some time now as navigation systems and mobile applications. This technology is also used in mapping work for landscape planning. A tachymeter is better suited for construction sites where GNSS measurements are hindered because of shadows, or if there are special requirements for height accuracy ( 100,000 m2

— Light to heavy soils — Material feed, dam construction, grading — Slope construction, fine grading with GPS control — Rock removal with ripper — Optional: crawler tractor — Optional: GPS / GLONASS machine control — Optional: level control with laser

Machine type Scrapedozer

capacity 5000–1,000,000 m³

— All-round machine for loosening, loading, transporting — Low ground pressure and excellent load distribution — Very economical for transportation distances of between 50 and 500 meters — Self-loading

Construction Machinery 217

Machine type Scraper

capacity 5000 to > 100,000 m³

— Not suitable for grading — Requires stable soil (wheel drive) — Self-loading capability — High transport capacity over long distance

Machine type Grading plane 9t

capacity 8 m³ up to 80,000 m²

— All soils — Grading in road and pathway construction — Complete operation from the tractor — Optional: various laser control systems — Optional: 3D machine control from terrain model possible — High accuracy and productivity — Very user-friendly

Machine type Grader 7–28 t

capacity 500 to > 10,000 m2

— Pure grading machine — Restricted use in earthworks — Used for road and sports grounds construction (paved surfaces) — Optional: sign with laser control for profile accuracy +/– 1 cm — Optional: GPS / GLONASS machine control from terrain model possible — Optional: height loss with ultrasound for level control — Optional: slope sensor for transverse slopes for roads 218

Machinery for Soil Transportation

Machine type Wheel loader Skid steer loader 3–15 t

capacity 5–1000 m³

— Loading, moving solid bulk material — Light to medium weight soil — Subgrade with high load capacity — Fast and agile for smaller quantities — Optional: concrete mixer blade

Machine type Track dumper 0.3–22 t

capacity 1–10,000 m³

— Suitable for moving earth material on non-stable soils — Transport distance from 5–500 m — Load volume 0.3–12 m³ — Good climbing performance (up to 25% slope)

Machine type Small dumper Wheel dumper 1.2–3.6 t

capacity 1–100 m³

— Use on stable ground — Suitable for roads — High traveling speed and maneuverability — Load volume 1–2.5 m³ — Dumper can be hydraulically rotated and tilted

Construction Machinery 219

Machine type Dump truck

capacity 200–100,000 m³

— Earthmoving, solid bulk material, gravel — Requires stable subgrade — Transport distances 100 to approximately 3000 m — Good traveling speed 10–30 km/h — High center of gravity and tilt height — Load volume from 9–18 m3 — Approved only for service roads (not for general traffic)

Machine type Trench roller 1.5–2.5 t

capacity 5–300 m³ 10–300 m²

— Backfilling of structures and trenches — Slim design — High compression coefficient — Good rate of climb — Maximum compression efficiency 50–70 cm

Machine type Tandem vibratory roller 2.5–15 t

capacity 10 to > 1000 m³ 10 to > 1000 m²

— Suitable for gravelly subgrade — Compaction depth effect: 20–60 cm — Limited suitability for earthworks (useable only on flat surfaces) — Poor climbing performance

220

Machinery for Soil Compaction

Machine type Vibratory roller 7–15 t

capacity 100 to > 10,000 m³ 100 to > 1000 m²

— Suitable for dams and landfills — Larger earth compaction projects — Good climbing performance, off-road mobility — Depth effect: 40–80 cm — Optional: built-in compression measurement — Optional: padfoot drums for deep compaction

Machine type Attached compactor 7–15 t

capacity 10 to > 1000 m³ 10 to > 1000 m²

— Small, portable, flexible — Ideal for embankments and backfills — Good depth effect in difficult soils — Interchangeable fixtures and a wide assortment of vibratory plates

Construction Machinery 221

“Rainbowing” an island off the coast of Dubai.

Construction Machines for “Rainbowing” Now and then the media reports another newly built island formation, for example in the Arab Emirates. Such projects can even be found via Internet map services. This is terrain modeling as well! However, in professional circles this particular technique is called “rainbowing.” We will not go into more detail here as to whether or not projects such as these are meaningful and/or sustainable. However, as a pure description, “rainbowing” looks like this: — Dredgers supply rock and sand, and dump the material into the water at a designated location until a stable underwater base is created. — Special ships blow out soil material, which has been sucked up a few kilometers from the seabed, onto the base. This is repeated until the sand base rises above sea level. — Construction machines model the visible, above sea level, form using what is called Sweet Sand, according to plans by the landscape architect. The “improved” sand is usually modeled to an average of about one and a half meters in depth. The unusual name refers to sand taken from landlocked sources, which has a low salt content. Without the nutrients found in this source and plenty of fresh water, plants would not survive the extreme climatic conditions. — Steel retaining walls, installed on the sides that are exposed to the sea, protect the islands against waves and erosion.

222

Construction Machinery 223

Grading in Practice

The following projects (including texts and image material unless otherwise stated) come from landscape architecture offices based in various countries and cultures. Some are offices with a small staff, and others are large companies with multiple locations. Some projects used digital terrain models and 3D machine control, while in others the contour lines were drawn by hand and implemented by hand. The projects also vary in concept and size, from town squares to residential areas, parks, and landscape designs. Despite these differences, all the projects have one thing in common: grading, in addition to the use of plants, is the most important design element for the landscape architects.

Practice 225

Ertingen-Binzwangen Flatbed Glide Ertingen-Binzwangen, Germany Land Baden-Württemberg, represented by the Regional Government Office of Tubingen Geitz und Partner GbR Landschaftsarchitekten Schrode Tief- und Strassenbau GmbH

The finished project.

The digital terrain model (enhanced representation) of the step pool ramp.

226

For the “Integrierte Donau-Programm“ (Integrated Donau program) of Baden-Württemberg, a flatbed glide was constructed in Binzwangen near Riedlingen. Due to straightening measures that began in the nineteenth century, the run length of the River Danube was greatly shortened, resulting in significant vertical erosion particularly in recent decades. In order to raise the Danube water level and hence the groundwater table again, an extensive preliminary investigation was led by the Institute of Hydraulic Engineering, University of Stuttgart, and a plan was conceived to reactivate a natural-looking river bend and to reduce the flow gradient over a length of 2.6 kilometers. This resulted in an approximately 2.1 meter increase in the water level at the downstream end of the project, which then needed to be gradually decreased over a short distance by the flatbed slides, so that the vicinity of Binzwangen would not be negatively affected. The objective of the detailed planning, besides ensuring the stability of the construction and the safe dissipation of floodwaters, was to ensure the hydroecological passage of the Danube, which typically has highly fluctuating water levels. The result of the evaluation was a detached step pool ramp with a continuous low-water flow and still water areas that were not subjected to the water current. For the contractor, this meant setting a total of 2700 tonnes of granite stones, each weighing 1.6 tonnes and having a maximum edge length of 1.5 meters, with a height accuracy of about two centimeters. This work could be carried out in dry conditions due to a sheet-piling wall. Consequently, the standard conditions of the contract had specified the difficult survey work, which would need to be done in the water or from a boat. The firm responsible for the project, Schrode Tief- und Strassenbau GmbH, chose to add a measuring, calibrated sorting grab to the crawler excavator, which was already equipped with 3D control. For this purpose, the firm first had to prepare a DTM of the planning, in which each individual stone was defined in terms of position and height. After this process, the stone could be picked up by the sorting grab and placed into the correct position. The height of the irregularly sized stones was initially estimated, then checked according to the edge of the sorting grab after being placed into position, and finally adjusted to the precise required level. A traditional survey would not have been economical in the pitched slope and at first not possible under water. The initial slope batter rail guidance for site managers and clients was swept away in the first flood. It was the 3D control that made the project economically and technically successful. An approval survey was conducted together with the client, which confirmed the high level of accuracy. The construction work was largely carried out alone by an equipment operator and a foreman (except for the sheet piling work), which is a remarkable achievement!

Practice 227

536.39

LEGENDE Planung

536.08 538.74 536.09

537.39

535.95 540.60

537.90

m

etrieru ng RP

mpe ,

3

537.44

535

536,20

538.34

538.41

538.14

534,22

538.14

535,77

538 m

14

534

,50

537.63

533,92

537 .71

7

537

Bootsausstieg in Form einer flachen Rampe (1:6), ausgebildet als Rasenschotterweg im strömungsberuhigten Oberwasser einer Schüttsteinbuhne aus Jurakalksteinen LMB 10/60

11

m

12/20 kV

536

534.05

533.10

532.53

13

23

533,32

29

533,02

533,47

535

25

16

537.45

533,37

22

537.96

53

538.10

8 m

538.10

m

m

532,71

78m

534 m

538,80

538.26

538.14

Schütts teinram pe:

538.33

538.11

538.23

538.34 538.20

538.63 538.32

538.23

538.21

538.26

538.27 538.23

538.24

538.36

W eg

539,33 =Bestand

538 29

538.54

539,35 = Bestand

Y 3x1x150

539.21

538.65

539.13

539.02

538.84

538.91

538.73

539.30

538.66

539.00

Anschluß an Asphaltweg Bestand

ttung aus Jurakalk

70m

LMB 5/40

tung aus Jurakalk LMB10/60

536 m

Plangröße:

Dipl.-Hyd. H. Kappich, Dipl.Ing. A. Eisner

Gezeichnet:

H. Kappich, S. Krieger

1385 x 565

Datum:

02.02.2009

Land Baden-Württemberg

Bauvorhaben:

Gegenstand der Darstellung:

Sanierung der Donau zwischen Hundersingen und Binzwangen, Bauteil 1 - Bau einer Sohlgleite Ausführungsplanung Lageplan Rampe

534.03

Lattenpegel 536.90

537.20

536,91 536.9

Maßstab:

1:200

Lattenpegel erhalten und sichern 537.45

539.06

538.84

538.97

538.77 538.95

538.65 538.7

538.47 538 32

Der Planverfasser:

Der Bauherr:

Datum:

Datum:

Plangrundlage: Vermessung durch Intermetric, Stuttgart, Juni 2008

Detailed design.

The excavator with 3D machine control on the jobsite.

228

Projekt-Nr. Art der Änderung:

e 537.42

538.82

5.1.2

Datum:

a b c d

537.18

538.75

538.60

Plan Nr.

537.17

Bootseinstieg mit Treppe 537.53 und Sitzstufen (siehe Detailplan 5.4)

538.60 538.89 Grundwassermessstelle 2003/568-0 erhalten und sichern

533.11 Steinschüt

539.00 538.87

538.98

532.96

534 m

536.86

Steinschü

537,46

Bearbeiter:

532.93 534.03

535,29

535,37

538 m

538.55

538.84 539.35

539 m

539.47 539.48

539.39

6,3 %

538.69

539.13

m

538.98

539,00 538.60

539,34

539.19

537

Nachkolk: 537.66

538.53

538.20

539 m

539.23 539.62

538,50

538.83

538.32

536,15 14 %

Geitz & Partner GbR Freie Garten- /Landschaftsarchitekten und Hydrologen Geitz · Kusche · Kappich Wegländer Straße 26 · 70563 Stuttgart - Vaihingen Tel.: 0711 / 735 716-0 · Fax: 0711 / 735 716-6 · E-Mail: [email protected]

Bauherr:

532.6

535 m

538.38 538.71

53

532,80

537.01

537.40

533

533 m

532.76

532.54

533 m

tung aus Jurakalk LMB10/60

537,60

Schotterrasenweg Planung 539,00

539.33

538.27

538.29 Profilstationierung von offiziellem Donaukilometer 2658 + 300 ausgehend entlang vermessener Flussmitte ermittelt 538 02

538.21

538,21

2

531,75

537.48

537.72

ef.

538.2

LMB 5/40

unb

538.59

Steinschüt ttung aus Jurakalk

13m

538,40

538.31

538.15

532.55

536.98 Steinschü

539,00 538.14 0

538.04

200 weg

538.04

538.64

Endschwelle zweireihig aus Jurakalksteinen LMB 10/60 einzeln gesetzt

532.27 533.42

537.66

R13

538.53

Baden - Württemberg Regierungspräsidium Tübingen Dienstsitz Riedlingen · Haldenstrasse 7 · 88499 Riedlingen Tel.: 07371 / 187-0 · Fax: 07371 / 187-359

536.18

Auftragnehmer:

533.07

534.01

538.38 538.65

532.92

532.51

Bezugshöhe R13=533,49

538.40

538.46

535 m

534 m

N

538,30 538.64

Auftraggeber:

Abteilung Umwelt - Landesbetrieb Gewässer

534.03

533.98

536 m

538,58 538.02

Dieses Projekt wird von der Europäischen Union mit Mitteln aus dem Fonds "ELER" kofinanziert 536.56

536.42

533.43

R11

538.45 538.47

538.16 538.11

537 m

Nachkolksicherung aus Jurakalksteinen LMB 5/40 geschüttet, überschüttet mit bauseits vorhandenem Donaukies.

536.77

k LMB 5/40

538.21

537.21

533.27

537.38

537.87 537.99

aus Jurakal

532.42

537.12

Bezugshöhe R11=533,83

537,65

538,15

üttung

532,84

534.01

532,34

37

34

537.91 538.10

Steinsch

534.01

533.33

31

538 m

Bezugshöhe R9 R9=534,17

536 m

0/60

532.44

532,71

538.23

538.29

532.04

532,68

537.72

538.14

alk LMB1

538.11 537.31

534.0

35

28

R7 Bezugshöhe R7=534,47

Jurak

538.

/15 (20)

Nachkolksicherung aus Jurakalksteinen LMB 10/60 geschüttet, überschüttet mit bauseits vorhandenem Donaukies.

Rampenfuß Schüttsteinrampe zweireihig aus Steinen LMB 10/60 einzeln gesetzt 532.64

532.28

Sohlriegel aus Jurakalksteinen LBM 10/60

533.36

537.47

Rieg elram pe:

537,92

537.99 538.12 538.15 538.05

533,05

538.03

Stein Bezugshöhe schü ttun 538.17 g ausR5 R5=534,77 Jura kalk LMB 10/6 538.17 0

m

537

537.93

R3 Bezugshöhe R3=535,07

38

533

t 3x95 g Al/S

536.87 ung aus

Stromleitung EnBW (20 kV)

+0,20 m

538.18

Freileitun

537.21

533 m

532.42

533,05

534.08

chütt

533.29

532,34 532.87

19

Steins

533.96 532.49

32

Bestand

537.65

537.55

537.38

535 m

533.17

36

26 532,68

537.98

538.16

39

532,71 532.27

533,37

538.16

538,15

534533.99 m

532,54

30 533,02

10

538.10

33

20

538.20

538 m

Schüttsteinrampe aus Jurakalk LMB10/60 geschüttet, überschüttet mit bauseits vorhandenem Donaukies.

Bezugshöhe R14=533,32

537 m

532,71 533,05

533,77

538.03

R14

537.35

17

537.60

538.00

538.00

27

533,32

533,67

533,62

.98

538.14

537.46

537.47

533,05

24

532.26

537.48

Bezugshöhe R12 R12=533,66

538.30 Grundwassermessstelle 2002/568-4 erhalten und sichern

538.26

Sohlschwelle (Fuß Riegelrampe) zweireihig aus Granitsteinen l=1,50m einzeln gesetzt

537.50

R10=534,00

537.03

534.04

533,37

532.18

533.42

m

537.70

537,40 R10 Bezugshöhe

m 534.54

m

18

533,97

536

4

R1

53213

533,67

533,62

KM -Ste in 40 0 534,27 538.21

538.14

Bezugshöhe R8=534,32

8

5

538.08

Profil 2658 + 551

538.36

R8

ca.

533,97

532.18

534.02

1

538.06

537.56

534.00

rin ne,

15 532.49

533,92

L2

Buhnen aus geschütteten Jurakalksteinen LMB 10/60

538 m

537,40

533,17

m

Spundwand als Wasserhaltung für Bau der Riegelrampe im Trockenen. Spundwand quer zur Donau verbleibt als Erosionsschutz (sohlgleich nachzurammen oder abzutrennen)

538.29

sser

533,67 533.15

534,27

535,37 538.16

538.40

533.32

533.55

538.34

538.39

533,97

531.99

538.31

538,40

53

Bezugshöhe R6 R6=534,62

12

538.14 538.44

538.41

537.

Bezugshöhe 537.24 R4=534,92

m

Nied rig wa

532.29

538.08

53535,87 537.70 7m

R4

53 5

2

533

534.06

m

7m

m

534,27

534,22

535,77 533.43 535,57

538.51

53 4

6

532.20

533.05

535,67 535,37

538.55 538.54

532.55

9

538.02

538.45

53

533.99

533.38

Jurakalksteinen LMB 10/60 im Böschungsbereich schütten

537.89

Bezugshöhe R2=535,22

.25

534,22

535,77

533.65

533.48 535,77

Plan 5.3

534.18 538.12

538.34

534

R2

533.80 533.84 535,57

DON AU

ssch nitt Ra

533.93

537.43

537.92

Läng

.40

.10

+ 344,51

533.19

532.90

537

537

Profil 2658

rme tric)

535,87 533.99 535,37 535,67

Spundwand (Baugrubensicherung und Ersoionsschutz)

0,00 m = Bezugshöhe Riegel

Erdleitung NA2XS2

533.49 Inte

533.76

536

kilom

*Bemerkung: Für Riegel 1 gelten Einschriebhöhen im Plan.

-0,05 m (Riegel 2-9) -0,07 m (Riegel 10-14)

Buhne aus Jurakalksteinen LMB 10/60

Jurakalksteine LMB 10/60 als Schüttung (Basismaterial für Rampen, Kolk, etc.)

+ 384,57

ssu ng

533.38

m

537.41

ansteigend von +0,60 m auf ca. 1,50 m über MW

Profil 2658

53 4

534.19

538 m 537.96

Donau

0

534.37

(Ve rme

,50

534.00

m

smi tte

+ 413

537

Flus

km 26

533.22

58,40

535.39

534.78

533.83

533.69

m

km 26

0

536,41

534.21

533.25

58,50

533.58

538.32

2

535

Riegelrampe: Riegel aus Granit, l=1,50m, Basismaterial aus Jurakalk LMB10/60, überschüttet mit bauseits vorhandenem Donaukies.

536.80

534.68

28

+0,40 m

+0,60 m

Riegelnummer und -verlauf

Höhenzonierung Riegel 2-14*

Schotterrasenweg

537.60

533.61 33.57

R3

538.71

/4

m

535.00

533.71

538.41

m

2658

536

Profil

538

1102

536.78

427,17

537.51

534.27

533.83

533.48

2658 +

535 m

534534.18 m

533.35

539.60

535.65

534.56 534.31

Profil

533.40

533.54

533.16

Beckennummerierung Riegelrampe Riegel aus Granitsteinen, l=1,50m

(Darstellung entspricht 2-reihigem Riegel)

Wiesenfläche / Vorland (Ansaat Wiese)

4,05

535.68

+ 47

535.31 535.55

Flussböschung (Ansaat Ufer)

9 10

533.75

m

534.88

2658

534.69

538.62

Profil

533.96

53 7

,94

535.05

Profil 2658 + 504

536 m

10

Gewässer (ca. Mittelwasserspiegel)

537.86

536.10 534.44

0813

Working with a measured and calibrated sorting grapple. Top left: Lifting the stone. Top right: Correct placement of the stone. Center: Check and correct height.

Profile with details pertaining to stone placement.

Riegel 4 Bezugshöhe 534,92

3m

Riegel 5 Bezugshöhe 534,77

Rasenschotterweg, Breite 2,5 m (Gesamtaufbaustärke 40 cm KFT 0/45, in die obersten 10 cm Humus eingefräst, verdichtet und angesät

Steinwurf zur Böschungssicherung aus Jurakalkwasserbausteinen LMB 10/60, mit Mutterboden übererdet und angesät, über die Böschungsoberkante ca. 1.5 m mit Gegengefälle hinausgezogen, zum Schutz gegen Erosion bei Vorlandabfluß

5,5

Wegrand

1,2 m

Granitwasserbausteine, L=150cm, B=75cm, hochkant als Riegel gesetzt (zweireihig), Überschüttung mit bauseits vorhandenem Donaukies.

Böschung oben

Böschung oben

Böschung unten

ca. Flussmitte

Böschung oben

Projektion Riegel R5 Darstellung in Profil 2658 + 474,05

m

Filter (min. 20cm) aus Jurakalksiebschutt 0/200

Uferlinie

Uferlinie

~MW

0,20m

Wasserlinie gem. 26.06.08

538.20 538.21 538,25 47,71

537.98

537.98

538,25 43,98

537.92

537.94

41.14

41.73

39.22

39.88

538.02

538,15

538,15

38,03

35,46

35.12

538.17 28.73 537,92 29,23

48.17 48.59

Auftraggeber:

Steinwurf zur Böschungssicherung aus Jurakalkwasserbausteinen LMB 10/60, mit Mutterboden übererdet und angesät, über die Böschungsoberkante ca. 1.5 m mit Gegengefälle hinausgezogen, zum Schutz gegen Erosion bei Vorlandabfluß Rasenschotterweg, Breite 2,5 m (Gesamtaufbaustärke 40 cm KFT 0/45, in die obersten 10 cm Humus eingefräst, verdichtet und angesät

geschüttete Buhne aus Jurakalkwasserbausteinen LMB 10/60, Überschüttung mit bauseits vorhandenem Donaukies.

Böschung oben

Böschung unten

Filter (min. 20cm) aus Jurakalksiebschutt 0/200

Abteilung Umwelt - Landesbetrieb Gewässer

Geitz & Partner GbR Freie Garten- /Landschaftsarchitekten und Hydrologen Geitz · Kusche · Kappich Wegländer Straße 26 · 70563 Stuttgart - Vaihingen Tel.: 0711 / 735 716-0 · Fax: 0711 / 735 716-6 · E-Mail: [email protected] Dipl.-Hyd. H. Kappich, Dipl.Ing. A. Eisner

Gezeichnet:

H. Kappich, S. Krieger

Plangröße:

1070 x 500

Datum:

02.02.2009

Bauherr:

Land Baden-Württemberg

Bearbeiter:

5,3

m

Bauvorhaben:

Uferlinie Wasserlinie gem. 26.06.08

0,20m

Gegenstand der Darstellung:

538,16 -31,49

538.10

538.11

43.00

45.37

538.15

538,16 -31,49

538.16 538,16 -31,49

34.30

536,18 -26,55

31.90

538.14

538.15 538.14 538.15 20.31 20.55 21.04

21.56 535,95

537.68 16.11

538.09

534.73

18.74 535,87

535,37

534.06

11.01

533.22 8.24 8,95

Scheitel Riegelbogen

9.93

532.87 532.90 4.67 5.14

533.77

532.89 3.99

9.39

533.07 535,77 2.51 2,51

Längsschnitt Rampe

535,87

533.36 0.21

533.77 -5.84

533.67 533.64

533.74 -7.24

-3.34 -2.95 535,87 -3,60

Scheitel Riegelbogen

535,77

535,67

-9.92 -9.88 535,37

535,89

535,87

535,57

534.01 533.99

534.73

535.43 535.35

-12.32

-15.59 -15.42

536,18

536.83 536.82 -18.13 -18.02

-13,08

537.68 537.59

536,41

538.58

-16,74

Station

-24.40

Höhe

-21.27 537,59 -20.94

Station

-20,95

Gelände Planung

Höhe

Sanierung der Donau zwischen Hundersingen und Binzwangen, Bauteil 1 - Bau einer Sohlgleite Ausführungsplanung Profil 2658 + 474,05 (Projektion Riegel 5) und Profil 2658 + 504,94 (Projektion Riegel 1)

+ 530m

Gelände Bestand (26.06.08)

Baden - Württemberg Regierungspräsidium Tübingen Dienstsitz Riedlingen · Haldenstrasse 7 · 88499 Riedlingen Tel.: 07371 / 187-0 · Fax: 07371 / 187-359

Auftragnehmer:

MW Uferlinie

Böschung oben

Granitwasserbausteine,L=150cm, B=75cm, hochkant als Riegel gesetzt (zweireihig), Überschüttung mit bauseits vorhandenem Donaukies.

ca. Flussmitte

geschüttete Buhne aus Jurakalkwasserbausteinen LMB 10/60, Überschüttung mit bauseits vorhandenem Donaukies.

5m

535,51

537.65

Dieses Projekt wird von der Europäischen Union mit Mitteln aus dem Fonds "ELER" kofinanziert

Projektion Riegel R1 (Rampenkrone) Darstellung in Profil 2658 + 505,94

24,31

537.60 537.62

16.94

535,17

15.90 16.01

533.93 534.05 534.07 9.85 10.08 10.11

Scheitel Riegelbogen

Bezugshöhe Riegel

Ende Riegel 5

Scheitel Riegelbogen

1,45

12,30

535,37

532.26 532.39 5.74 6.21

534,77

532.16

532.40

2.05 535,37

534,72

-9,00

534,97

532.55 532.51

-3.75

534.03 534.00 -10.12 -10.02

-6.24 -6.14

537.22 536.96 -15.41 -14.92

Station

535,37

537.28 -16.13

537.53 -19.50

Höhe

535,52

537.90

Station

-14,94

Höhe

537,47

Gelände Planung

-18,65

Gelände Bestand (26.06.08)

-20.52

+ 530m

Maßstab:

1:100

Plan Nr.

5.2.4

Datum:

Projekt-Nr.

0813

Art der Änderung:

a b c d e Der Planverfasser:

Der Bauherr:

Datum:

Datum:

Plangrundlage: Vermessung durch Intermetric, Stuttgart, Juni 2008

Practice 229

Erlentor Stadthof Basel, Switzerland Westpol Landschaftsarchitektur The urban Stadthof, with its large concrete block surface, is a central meeting place in the Erlentor residential complex. The landscape architects were able to meet the complex technical and design requirements by creating an unusual surface pattern with the concrete blocks. This interesting pattern is the result of two different joint arrangements, each forming a honeycomb pattern that overlaps with the other, but is rotated at a 90-degree angle. Four stones fit together to form a main unit, which makes them look larger than they actually are. The concrete blocks were specially developed for the Erlentor project and manufactured by A. Tschümperlin AG. Two type 1/2 hexagonal stones fit together to form a module that can be quickly mechanically removed from the pallet. The tenons on the blocks ensure uniform joint widths. The base and joint filler are made of stone chippings. The surfacing was installed on a gradient of 1.5 percent.

The Erlentor Stadthof illuminated.

230

Context, not to scale.

The pavement pattern before gritting.

Joint pattern and concrete pavement, not to scale.

Practice 231

Swiss Cottage Open Space London, England Gustafson Porter The design for the Open Space is centered on a sculpted grass landform that wraps around an interactive water feature. The sculpted landform becomes a natural amphitheatre for community cultural events organized by the Swiss Cottage Library and theater rehearsals for the adjacent Hampstead Theatre. In summer, the landforms turn into an urban beach, with picnicking families and friends watching people cooling off in the water feature. It all started with a simple concept sketch for a competition in 1999, drawn over our analysis of site constraints and movement lines. We translated the sketch into a clay model, measuring the height of the proposed landform using metal pins. The forms were refined in shaping clay. From the clay model, we produced a rubber mould and eventually a plaster cast model. This we sent off to a 3D scanning bureau. Once we got the 3D scan back, we had to simplify the 3D model in Form-Z in order to work with the files. We draped a site grid over the resulting model and cut sections through the site at 5m center. We refined the sections in CAD, reducing the steepness of slopes where necessary (our civil engineers had advised maximum 55% slopes on the London clay subsoil to avoid slippage). The resulting levels were then transferred onto a plan. Construction started in 2005. First a simple land-drainage system was laid down. The landforms were built up using crushed site waste (old brick walls and pavement subbases), compacted in layers. This was topped by a layer of subsoil. A manufactured sandy topsoil of a minimum 200mm depth was laid over the subsoil in the turf areas to ensure good drainage. In the areas, where the slopes are generally below 30%, the soil is not reinforced. For the steeper slopes, a root zone consisting of a sandy soil mixed with polypropylene mesh grids manufactured by Netlon Ltd. was used. The contractor set out the levels with laser equipment, with stakes marking the finished levels at 10m centers. The stakes were connected using lines perpendicular to the slopes to allow us to check against the sections. We often specify that soil should be irrigated for 48 hours after installation to speed up settlement. However, as the irrigation had not been installed at this point, the contractor lightly compacted the soil by foot. Our soil scientist carried out infiltration tests to make sure that subsoil and topsoil had not been over-compacted. On approval, any uneven soil settlement was patched up and the turf laid by the contractor. The landform was fenced off for two months to allow the turf to take root, after which it was opened to the public in 2006.

Swiss Cottage Open Space after completion.

232

Concept sketch.

Clay model.

Presentation plan.

Practice 233

Profile view.

Rough earth sculpture.

234

Manual compaction of the topsoil before laying the turf.

Laying the turf.

Erosion control and stakes with cords profiles.

Ergonomic terrain modeling.

Practice 235

Northumberlandia Cramlington, England Charles Jencks and the Banks Group Northumberlandia is a landmark feature designed by world-renowned architect Charles Jencks, which celebrates the earth’s natural power and the human ability to reshape the landscape into a dramatic form. Lying at the entrance to southeast Northumberland, near the town of Cramlington, the landform is up to 34 meters high and 400 meters long. It is the centerpiece of a 14.5-hectare public park. Northumberlandia is constructed from rock fill material from the neighboring Shotton Surface Mine; this forms the core structure of the landform. This was placed in 1-meter layers to create the shape of the landform, to within 1 meter of the final surface, in order to allow for a covering clay subsoil capping and 100mm of topsoil. The steepest gradients that are not reinforced are 1:1.5. On the steeper slopes it has been necessary to design and implement a system of earth wall reinforcement using a geo-grid system and gabion baskets.

Sketch by Charles Jencks.

Right: Contour diagram (not to scale) of Northumberlandia.

236

Practice 237

Model.

Aerial view after completion.

238

Northumberlandia after completion.

Practice 239

SGI/Google Corporate Headquarters Mountain View, California, USA SWA “We were presented with a wonderful design challenge,” says Dan Tuttle of SWA’s San Francisco office. “There was the City mandate for a park, the SGI need for 500,000 square feet of highly amenitized R & D and office space, a 12-foot grade change, and, overlaid on it all, a highly complex web of public and private circulation.” The varieties of movement became a major theme in the design. This creative collaboration led to two key planning decisions: first, to treat the campus and park as one landscape; and second, because of the large building footprints, to assert the presence of the landscape by raising the buildings and locating most of the 1700 parking spaces below podium level. A series of terraces both capitalizes on, and masks, the existence of an 1100-car garage beneath the campus, which accounts for two thirds of the required parking, and allows the buildings to remain two to three stories in height while providing an open space ratio of about fifty percent. “It’s a very good case study for both grading and parking as they are intertwined here,” says René Bihan, SWA San Francisco.

The project is best understood by looking it up on Google Earth (author’s note).

Terrain modeling plan for Google headquarters.

240

Top right and center: The terraced landscape results from raising the building complex onto a platform.

Top left and left: Terrain modeling plans for Google headquarters.

Practice 241

Desert Ridge Marriot Phoenix, Arizona, USA SWA The building program, which includes the 1000-room hotel, spa, restaurants, and day services, is the largest hotel in the state of Arizona. A four-story height limitation led to the creation of a very long, horizontal building configuration, which we conceptualized as large mesas, framing significant views of the McDowell Mountains. The grading played a significant role in focusing those views through the creation of a system of ridges and arroyos. The arroyos work as the primary pedestrian circulation; they are filled with indigenous plant material and have the added benefit of creating large shade corridors. It’s hot in the desert, so having a deep shade-filled arroyo was both esthetic and functional in how the project performed. The arroyos extend to the parking lot, picking up surface drainage and creating a shade corridor in a heat island. Ridges were also strategically formed to scale down the functional spaces while addressing split building levels.

Examples of the many terrain modeling plans for the complex project.

242

Arroyos with three functions: pedestrian circulation, shade provision, and rainwater infiltration.

Practice 243

2500 Hollywood Way Burbank, California, USA SWA This 15-acre redevelopment of a mixed-use parcel includes an office, hotel, restaurant, conference center, and parking. The client’s goals of creating an identity for the property while clarifying circulation were achieved with landscape infrastructure and planting solutions. Unique approaches to planting in the large paved surfaces met the larger Sun Valley Watershed goals of stormwater infiltration while creating a comfortable outdoor open space for users. The Landform Garden at the hotel entrance is a component of the outdoor living room that interprets the nearby Verdugo Mountain Range. The landforms in the garden have slopes greater than 2:1, made possible by the use of a new erosion-countering technology from Invisible Structures called Slopetame2. The slopetame product stabilizes the soil and allows the installation and growth of plants. It acts as both a sculptural element and a natural mound for infiltration. Surrounding the landforms are a series of sedimentary concrete walls with metal benches that carve out seating spaces. Parking lots with integrated bioswales surround the development. A barrier was designed to minimize the views of cars, using three-foot-high berms and plant material. All of the parking lots slope towards the south of the site, where runoff can be directed. Curb cuts along the edge of the parking lot allow the water to enter a bioswale located at the southern edge of the parking lot. The bioswale filters the runoff before it enters a storm drain. This reduces the amount of pollutants entering the watershed. Integrated approaches to landforms and slopes played a key role in the overall design.

Detailed map, Landform Garden.

244

Landform Garden, terrain after planting.

Landform Garden, view from the interior.

Slopetame2 erosion mats after installation.

Practice 245

Qiaoyuan Wetland Park Tianjin, China Turenscape Landscape Architects In the northern coastal city of Tianjin, a former shooting range has been transformed into a low-maintenance urban park by changing its topography. Besides offering opportunities for environmental education, and creating pleasant esthetic experiences, the purpose and function of the park is to retain and purify stormwater.

Bird’s-eye view of the park from the southwest.

246

Grading plan for Qiaoyuan Wetland Park, plan scale 1:5000.

Practice 247

Victorian Desalination Project Victoria, Australia ASPECT Studios The Victorian Desalination Project is a large-scale infrastructure and ecological rehabilitation project, located in a visually, culturally and ecologically sensitive coastal site in south-eastern Australia. Land-forming earthworks were a central design strategy for the project, used to integrate the built form of the process plant with the landscape. An understanding of coastal geomorphology informed the design of the constructed dunes. These dunes were designed as visual and acoustic screening as well as being ecological features. The soil profiles were composed to ensure optimum conditions for plant growth. The dunes also served as a means to deal with the significant volumes of spoil produced from the bulk earthworks, and had a flexible design basis so that their arrangement could be adjusted depending on construction requirements, as well as the volumes and condition of the excavated material. The landscape architects ASPECT Studios worked closely with the project architects and engineers to ensure that the operational, process, visual amenity, and environmental performance requirements for the project were met. The constructed dunes and plant buildings were designed in such a way that the visual impact of the structures was minimized. The height and arrangement of the constructed dunes was carefully considered and integrated with the design of the roof of the main building of the processing plant, which was configured as a green roof. This resulted in the mitigation of visual impacts and ensured that the green roof and re-vegetated constructed dunes are the dominant elements in the landscape as seen from sensitive public viewpoints.

Contour map of the entire project.

248

Detail of the contour plan.

Detail of a sand dune.

Practice 249

Millennium Parklands Sydney, Australia PWP Landscape Architecture In 1997 HASSELL invited PWP to take the lead in designing a park of over a thousand acres. Surrounding the site of the 2000 Sydney Olympics at Homebush Bay, the site is slightly larger than New York City’s Central Park, but unlike Central Park or Golden Gate Park in San Francisco, it does not lie within an urban grid and therefore has no formal boundaries.The park board and the Olympic Coordinating Authority (OCA) envisioned a park for the twenty-first century that would contrast sharply with such nineteenth-century creations as Sydney’s Centennial Park. The first task was to dig out the contaminated soil, and then a series of positive landforms were situated. Spiraling paths lead up to the tops of the landforms, which range from twenty to sixty meters in height and provide orientation from various parts of the park as well as views over trees to the Olympic Center, the river and the bay, and in the distance, to the skyscrapers of downtown Sydney. Since the earth caps of the landforms are thin, tree planting was kept to the deeper soil at their lower edges and shallow-rooted native grasses were sown on the thin caps.

A terrain model. PWP always works with models, even for the terrain modeling of the Millennium Parklands. Aerial view of the Millennium Parklands, Sydney.

250

Contour map of a landform.

Practice 251

Appendix

Exercises in Grading Most exercises on the following two pages are based on material used in grading courses at American universities. In this context, the author would like to thank Professor Sadik C. Artunc, FASLA. The solutions were modeled using Autodesk Civil 3D. The exercises can be done analog using a pocket calculator, a ruler (or preferably a triangle), a pencil and an eraser, or they can be done digitally. At the landscape architecture degree program at the HSR – University of Applied Sciences Rapperswil, students are expected to be able to complete the exercises analogically in the first semester and in the second semester digitally.

Exercises 253

Town square with gradient Exercise: Construct the square on the site. Conditions: — Maintain the specified gradient on the square. — The slope should be 10%.

254 Appendix

Exercises 255

Buildings and seepage swales Exercise: Water from the roof surfaces of buildings and the surrounding terraces should infiltrate on site. Conditions: — Due to the slope situation, the water is channeled by two trenches. — The longitudinal and side slopes of the trenches can be chosen at will. — Both trenches end in seepage swales. — A saddle point is located on the slope side, outside of the area to be drained, and is lower than the square, but slightly higher than a contour line elevation (37.01). With this trick you can lead the contour lines back in front of the elevation spot, making the contour plans much clearer.

256 Appendix

Exercises 257

Road Exercise: Starting from point 95.30, construct the planned contour line of 95.00. The details on the plan must be observed. Conditions : — The road is 6 meters wide and has a curb on both sides that is 25 centimeters wide and 10 centimeters high.

258 Appendix

Exercises 259

Parking lot I Exercise: Grade the parking lot. Rainwater management is a priority. Conditions: — The water in the parking lot, which has 5% longitudinal and 2.5% lateral slopes, flows over a pavement gutter into a shaft and from there into the swale on the right-hand side. The water from the remaining surface, before the lot leads to the road, is collected by a box gutter and channeled into the swale on the left-hand side. — The water-permeable paving is edged with a curb that is plane with the paving surface. A shallow trench surrounding the lot collects water from the slopes. It seeps into the sink along with the water from the parking lot. Both swales are connected to a pipe that serves as additional drainage in case of prolonged rainfall. 260 Appendix

Exercises 261

Building with access road Exercise: Create a terrain model for the building and the driveway. Conditions: — The water from the roof surface and the paving must infiltrate on site, or it can be channeled into the trench along the road. A concrete pipe, with a soil cover at least 50 centimeters deep, carries water from the trenches under the driveway. — Box gutters on the driveway collect the water and channel it directly onto the site. — Access to the building is continuous. — The maximum slope angle is 2:3. — Specifications for the trench: bed width 1.5 meters, minimum gradient along the central axis 1%. — The existing trees must be protected: protection area = canopy drip + 1.50 meters. — Specifications on elevation spots and gradients at all important areas. — Because of the small scale, this is a conceptual grading. Assumptions about the trench vertices can be made at will.

262 Appendix

Exercises 263

Ramps Exercise: The retirement home is to be made wheelchair accessible by ramps as well as having a direct access route with two flights of steps. Conditions: — Rainwater from the roof and surface pavement must be channeled into the lake situated to the south. — Box gutters collect the water on the surface and channel it laterally onto the terrain. — Maximum ramp slope of 6%. — The trench bed is displayed as dashed lines. — Maximum slope gradient of 1:3. — The shaft in the center area collects the water. One pipe carries the collected water underground to the lake.

264 Appendix

Exercises 265

Noise barrier Exercise: A path is to lead to a viewing platform (shaded area). A wall of earth is to be modeled that will serve as a barrier against noise from the expressway located to the west (outside of the plan) and will visually separate the area from the parking lot. Conditions: — The earth wall can be up to 4 meters high. — Rainwater from the path must infiltrate laterally. — Maximum slope gradient of 1:3.

266 Appendix

Exercises 267

Tennis court Exercise: The tennis court with building and observation deck is to be integrated into the grounds. Conditions: — The water from the pavement surface must be channeled into two trenches. — Box gutters collect the water on the surface. — The specified gradients on the surfaces are to be observed. — Maximum slope gradient of 1:3.

268 Appendix

Exercises 269

Parking lot II Exercise: A parking lot is to be graded along an existing road. Conditions: — The parking lot is surrounded by a curb 10 centimeters wide. — A sludge collector collects water from the parking lot, which is then channeled through underground pipes into the side trench. — The specified gradient must be observed.

270 Appendix

Exercises 271

Terraced houses Exercise: The water from the roofs and pavement is to infiltrate on site or be channeled into the body of water situated to the south. Conditions: — The following minimum and maximum slopes must be observed in the terrain model: – Access 1–5%, – Trench longitudinal axis 2–10%, – Slope gradient 2–33 %. — The water from the pavement must not flow onto public roads. 272 Appendix

Exercises 273

Glossary

Alignment A series of 2D coordinates (northings and eastings), connected by lines, curves, or spirals used to represent features such as road centerlines, edges of pavement, sidewalks, or rights-of-way. Alignment stakeout The process of placing stakes in the ground at control points on a site that is being developed. ASCII American Standard Code for Information Interchange. ASCII Grid format A grid format in which each pixel has an elevation attribute. Azimuth An angle measured clockwise from a reference meridian. Also known as north azimuth. It can range from 0 to 360 degrees. A negative azimuth is converted to a clockwise value. Ballast Crushed rock with a grain size of 3–22 mm. Bench A level, narrow stretch of land interrupting a slope. BIM Building Information Modeling. Breakline A line connecting data representing a specific Digital Geophysical Mapping (DGM) element such as a ridge line, the edges of a road surface, a toe of a slope, the centerline of a road, or the flow line of a trench or watercourse. buildingSMART BIM Initiative (www.buildingsmart. org). Brusch layering Bioengineering slope stabilization technology. CAD Computer Aided Design. CAM Computer Aided Manufacturing. Clothoid spiral A spiral in which the curvature is

a linear function of its length, so that the degree of curvature is zero when it meets the tangent and then increases to match the curvature of the adjacent curve. COGO Short for Coordinate Geometry. Cohesion “In soil mechanics cohesion is related to adhesion, meaning the bonding forces in cohesive soils. It is only seen in soils consisting of very small grains [...], such as clay. Cohesion ensures the inner adhesion of the individual particles in soil or fine-grained aggregate.” (German original under: de.wikipedia.org/ wiki/Kohäsion_(Bodenmechanik), de.wikipedia.org, 2013) Compound spiral A spiral that provides a smooth transition between two adjoining curves of different radii but in the same direction. It has a finite radius at each end.  Contour line A line that connects points of the same elevation or value relative to a specified reference datum. Coordinates A system of coordinates is used to navigate space. The position of a point in space is described by the three planes of X, Y, and Z (easting, northing, and elevation). Courtyard drain This drain collects water at specific points. It is used for small-scale, paved or stone-flagged areas. Cut See Cut slope. Cut slope The slope created when the footprint falls below the existing ground line. The resulting slope matching up into the existing ground is called a cut slope because the existing ground must be cut (removed) during construction.

Glossary 275

Dam A dam is an embankment. The dam consists of a fill crest and a slope on both sides with a calculated gradient. Data band A graphic frame in road planning that is assigned to a longitudinal section view. The data band contains annotations for the profile or section view, as well as for the parent horizontal alignment. Some common annotations include elevation data, stations, and cut/fill depths. Daylight line A line showing the line of zero cut or fill within the job area. For grading objects, it represents the target line produced by grading a specified DEM (Digital Elevation Model), distance, or elevation. Decompaction Change in soil compaction by means of aerating. Delaunay triangulation A triangulation that is devoid of other points within the circle defined by the vertices of any triangle. DEM Digital Elevation Model. DGPS Differential GPS. Digitizing Translation of an analog signal into digital data, for example, by scanning an image. Drainage Drainage system in the soil structure.

in the form of an irregular triangular network (TIN). DXF files Data Exchange Format. Supports the original AutoCAD DWG format as ASCII data. The DXF format is NOT standard and changes with each new version of AutoCAD. Easting A linear distance eastwards from the NorthSouth line that passes through the origin of a grid. Equivalent to the X-coordinate in an XYZ coordinate system. Elevation The vertical distance from a datum to a point or object on the earth’s surface. The datum is considered to be at sea level. Equivalent to the Z-coordinate in an XYZ coordinate system. Elevation point A point that marks an elevation change but does not break the horizontal geometry. Erosion Removal of fine earth by water or wind, often as a result of human activity. Field book The permanent detailed record a surveyor makes of all observations made in the field. Fill slope The slope created when the footprint falls above the existing ground line. The resulting slope matching down into the existing ground is called a fill slope because material must be brought in to fill the area during construction.

Drainage divide In most cases, a drainage divide is a ridge of land that separates waters flowing in two different directions. If the ridge of the watershed is located on the valley floor, it is called a valley divide.

Filter layer A layer that prevents the transport of soil components in layers above or below it, for example, geotextile or gravel.

DSM Digital surface model. The DSM displays the earth’s surface with vegetation and buildings.

Fine earth Mineral soil components with a particle size diameter of less than two millimeters.

DTM – DEM Digital Terrain Model – Digital Elevation Model. The digital storage of the elevation data of a site

Foundation layer Layer for the load distribution on the base.

276 Appendix

Gabions Wire cages filled with stones. Geotechnical Engineering Geotechnical engineering refers to all the individual disciplines of civil engineering that deal with the formation of structures in the subsoil: earthworks and foundation engineering, soil mechanics, rock excavation and tunnel construction, and so on. Geotextiles Polymers form the basis for geosynthetics. They are processed into various products such as geotextiles.

tains attributes and relationships (topology). landscapingSMART Efficient production and use of a digital data model in landscape architecture. LandXML This format displays the topology of a TIN in a nodes and elements list. The format is ideal as an interface for TIN, because all information pertaining to all breaklines is retained. LandXML is an open source format and is now supported by many GIS products and manufacturers.

GIS Geographical Information System.

Levelness Measuring the deviation from under a four-meter batten.

GNSS Global Navigation Satellite Systems.

LIDAR Light Detection and ranging.

GPS Global Positioning System.

ME value Measuring unit for plate load test.

Grading Artificial transformation of the ground surface by cut or fill techniques using soil and subsoil material. The terms terrain modeling and grading are used synonymously.

Northing A linear distance northwards from the EastWest line that passes through the origin of a grid. Equivalent to the Y-coordinate in an XYZ coordinate system.

Grain The composition of mineral soil matter of different grain sizes (stones, sand, silt, or silt and clay).

pH Measured value for the concentration of acids in solutions (for example, ground water).

Gravel Mineral base component having a particle diameter of two to sixty-three millimeters.

Profile An object that contains elevation data along a horizontal alignment or other line.

Humus All dead organic matter in the soil, more or less metabolized.

Profile view Object that manages the graphic display of profile data objects within a drawing. A profile view is essentially a graph with two primary axes: the x-axis represents horizontal distance along the referenced horizontal alignment (or other linear feature). The y-axis represents elevations. Profile view objects can also include grid display components and data bands.

Interpolation The process of determining the position of an elevation point, based on two known highlights in terms of elevation points. Landscape models Landscape models reproduce the objects of the landscape in a flexible vector format. They consist of thematic layers (for example, a transport system). Each level includes geo-referenced point- shaped, line- shaped, or plane-shaped objects. Each object con-

Runoff coefficient Percentage that takes into account the nature of areas subject to precipitation, and the resulting runoff delay.

Glossary 277

Rough grading Design of the terrain course with substrate material. Sag curve In a profile, a vertical curve at the bottom of a valley or similar location where the grade leading into the curve is less than the grade leading out of the curve. In a sag curve, the point of vertical intersection (PVI) for the tangents is below the curve. Sand Mineral soil component with a grain diameter of 0.06 to 2.0 millimeters. Seepage conduit Underground conduit for collecting and disposal of slope and seepage water. Seepage layer Layer for the draining of water. Simple spiral A spiral where the large radius end has an infinite radius and the small radius end has a finite radius, therefore providing a smooth transition from a tangent (infinite radius end) to a curve (finite radius end). Slope An area of terrain with an inclined surface that was created by cut or fill work. Slope (percent) A method of reporting ground inclination in which the change in elevation is expressed as a percentage of the horizontal distance traveled. For example, if the ground rises one linear unit (meter or foot) over a horizontal distance of five units, the grade is 20%. Slope (ratio) A method of reporting surface inclination as a ratio that expresses the horizontal distance in which the elevation changes by one linear unit. For example, if the ground rises three units over a horizontal distance of fifteen linear units (meters or feet), the slope is 5:1 (5 to 1).  Sludge collectors Separation unit with odor trap

278 Appendix

that retains and removes undesirable substances in drainage systems, such as sand, gravel, floating substances. Soil compaction Irreversible changes in soil structure caused by pressure and resulting in the reduction of pore space and the destruction or disruption of the cavity system. Soil skeleton Proportion of mineral soil components with grain sizes of over two millimeters in diameter (stones, gravel). Soil structure Spatial arrangement of the mineral and organic soil components differing in the shape and size of cavities (which contain water or soil air). Soil water Moisture in the soil, contained in the medium and fine capillary pores. Soil water tension The force with which water is held in pores (especially capillary). Stakeout Localizing structures on construction sites in the horizontal. Stationing The labeling that provides a reference when talking about a specific point along the reference baseline. Subgrade Leveled and compacted surface of the base layer. Substratum Layer of substrate material. Substratum layer Totality of the superstructure for surface coverings with the exception of the top layer. Superstructure All the layers above the ground, which carry and distribute the loads of traffic. The superstructure may consist of several layers, for example filter layer, foundation layer, base layer, and cover layer.

Tangent A straight line segment that forms part of a horizontal alignment or profile. Tangent distances are measured as the horizontal distance between the two end points. Tensiometer Measuring device equipped with a pressure gauge to determine soil water tension. Usually installed permanently in a selected place. Terrain Relief shape with certain grades, for example, uniformly graded 30 to 35 percent. Terrain modeling See grading. Throughfall Vertical extension of the tree canopy periphery. TIN Triangulated Irregular Network. Points closest to each other are joined to create irregular triangles; the resulting surfaces form a terrain model. Topsoil Humus-rich, dark-colored, and often containing a high concentration of roots. It is where most of the earth’s biological soil activity occurs. Top view The view of a site in a straight line from an elevated position. Turf substratum layer Special vegetation layer for lawns with respect to water, nutrient balance, and sustainability. Vector graphics The storing of graphic data based on the coordinates of individual points, lines, or geometric curves. Vegetation layer Soil containing a high concentration of roots and consisting of one or more layers, for example, subsoil, topsoil. Waterlogging Wetness from rainwater due to poorly drained soil layers.

Glossary 279

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Illustrations

t: top, m: middle, b: bottom, r: right, l: left Cover: André Lehner, Zurich Albanese & Lutzke, Albanese Paul: 213 Archives of Swiss Landscape Architecture SLA, Rapperswil, from the estate of Ernst Cramer: 35 to 38 asp Landschaftsarchitekten / Neuenschwander: 47, 48 Irchelpark, University of Zurich Awestra, Wollerau: 206, 210 Baan Iwan: 99 Bavarian Environmental Protection Agency: 155 Bolliger Peter: 60 t r, 60 m r Burkart Hans-Peter: 60 t l, 97 Cavigelli GaLaBau: 156 m, 159 m Deponie  Tüfentobel, St. Gallen: 197 ETH-Library Zurich, collection of old prints: 31, 186 l Fluss Michael: 16, 156 t, 156 b, 158 t, 158 m, 159 b, 160 l, 169 Fürst-Pückler-Museum Park Foundation and Schloss Branitz: 32, 33 Geitz + Partner, Freie Garten- und Landschaftsarchitekten, Stuttgart: 117, 118, 124 Gletschergarten Lucerne: 195 Harradine Golf: 24 r, 93 b Heidelberg University Library: 20 t r, 20 b Henz Ludwig: 31 Ian White Associates, Landscape Architects & Planners, Stirling, UK: 53 to 57 Inauen Bruno, Inauen-Koch and KIBAG, Uster/Zurich: 121 Lehner André: Cover, 2, 18, 58, 68, 108, 132, 152, 178, 200, 212, 224, 252, 274, 280, 286 Leica Geosystems, Heerbrugg: 185 Lukas Domeisen AG: 106, 181 Maurer Yves, HSR: 60 m l, 202 b l, m, r MTS, Hayngen: 207 Orient Irrigation Services, Heiko Heinig: 93 t, 113 b, 222, 223

284 Illustrations

Pöyry Infra AG, Laager Peter: 119 m, b Rehau AG: 160 r RIBA Library Drawings Collection: 184 Rutishauser Landschaftsarchitekten: 70 t Städtische Sammlungen Cottbus, Stadtarchiv: 30 Südwestdeutsches Archiv für Architektur und Ingenieurbau, Karlsruhe University, work archives of Günter Behnisch & Partner: 42, 43 Südwestdeutsches Archiv für Architektur und Ingenieurbau, Karlsruhe University, work archives of Günter Behnisch & Partner, Kandzia Christian: 41 l, 44 swisstopo: 21 Dufour map detail reproduced with permission of swisstopo. 24 l Türlersee (BA071439), reproduced with permission of swisstopo. SYTEC, Sacchetti  Toni: 122, 123, 129 Toller Unternehmungen AG. Garten, Strassenund  Tiefbau, Eschenbach: 215 to 221 UMS GmbH, Umweltanalytische Mess-Systeme: 112 Utrecht University Library: 23 De Boven-Merwede, Nicolaas Cruquius, 1730. Walti Ruedi: 230 Williamson Keith: 15 b Zentrum Paul Klee, Erwin Schenk: 101 Zurich Central Library: 20 t l Map of the Confederation by Konrad  Türst, 1495/1497.

All other illustrations are from the author.

Tables Tables are provided by the author or were traced by him.

Biographies

Michael Fluss Born in 1957 in Zeven, Germany. Graduated in 1987 as a landscape architect from the Technical University, Berlin. From 1987 to 2006, freelancer in engineering firms (garden and landscape design). Specializes in CAD object planning, land consolidation, and green space planning, designing amphibian control systems on roads. From 2006 to 2008, research assistant at the HSR – University of Applied Sciences Rapperswil, Switzerland. Project on “Stormwater management system for Swiss garden and landscape design.” Runs his own planning office in Freiburg, Breisgau. Véronique Durand Hilfiker Born in 1969 in Basel, Switzerland. From 1988 to 1997 studied Iberoromance philology, French literature, and linguistics at the University of Basel (MA Master of Arts). From 1998 to 2008, editor at Birkhäuser Publishers. Freelance editor since 2009. Since 2009 also administration officer at the University of Basel. In 2010, project assistant, and in 2013–2014, research assistant at the HSR – University of Applied Sciences, Landscape Architecture Degree Program. André Lehner Born in 1964 in Zurich, Switzerland. From 1983 to 1989 studied at the ETH Zurich (Dipl. physicist ETH). Since 1989 has worked in various positions as a software engineer, most recently at the Zürcher Kantonalbank as technical project manager. Outside of his professional activities, he has traveled extensively in Latin America, camera in hand. In 2003 and 2007 he was awarded a solo exhibition of his photographs from Brazil, Chile, and Argentina at the Gallery of the Migros Club School in Zurich. Ulrike Nohlen Born in 1972 in Reutlingen, Germany. 1998 degree in Geology at the University of Tubingen. From 1996 to 2001, worked at an engineering firm (engineering geology). From 2001 to 2008, responsible for the GIS/CAD pipe network analysis and construction supervision (underground pipe laying) of a municipal utility. Since 2008, has worked at Schrode Tief- und Strassenbau in the fields of estimating, construction management, building surveying, and accounting, and at Maschinentechnik Schrode AG Hayingen in the fields of research (geotechnical) and development (3D excavator controls). Peter Petschek Born in 1959 in Bamberg, Germany. From 1979 to 1985, studied at the Technical University of Berlin (Dipl.-Ing. Landscape Planning). From 1985 to1987, studied at Louisiana State University, U.S.A. (MLA: Master of Landscape Architecture). From 1987 to 1996, worked at various landscape architecture firms in the U.S.A., Germany, and Switzerland. Since 1991, Professor at the HSR – University of Applied Sciences Rapperswil, Landscape Architecture Degree Program, with a main focus on execution planning/ terrain modeling and information technology.

Biographies 285