10th INTERNATIONAL CONFERENCE ON Rainwater Catchment Systems
10 - 14 September 2001, Mannheim
| AUTHOR: Dipl.-Ing. Harald Kraft, Schmiljanstraße 7, 12161 Berlin. Tel.: +49 - 30 - 851 66 16 / 85 96 11 94 Fax: +49 - 30 - 852 23 95 E-mail: kraft@ib-kraft.de |
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Auroville - India |
Beijing Olympic Green |
Introduction
Until the mid-90’s in Germany, all storm water was treated as contaminated surface runoff and diverted away in drainage systems. Drainage took precedence over infiltration. However, with the amendments in the state water laws, the water resource management objectives became reversed, and decentralised infiltration began to take precedence over drainage. Storm water management in urban areas is basically subdivided into that for private plots and that for public property, including streets public squares, parks, or other open areas. It is primarily carried out through retention, reuse, and infiltration. Drainage of storm water as wastewater can now be seen as outdated. Storm water management intended to relieve the sewer network, infiltration to enhance groundwater recharge, and on a limited scale, the storm water collection for reuse, are finding increasingly more application in modern development projects.
The Early Integrated Water Concepts
(1) Project IBA Block 6, Berlin-Kreuzberg
Within the framework of the Internationale Bauausstellung (International Housing Exhibition), Berlin 1987, a pilot project in the area of experimental housing and town planning, with a strong ecological emphasis, was to be implemented in Block 6 under the auspices of the Federal Ministry of Regional Policy, Building and Urban Construction (Bundesministerium für Raumordnung, Bauwesen und Städtebau).
The objective of this demonstration project is maximum conservation of water resources through measures of reducing the drinking water consumption and environmental pollution caused by waste water. The rainwater was harvested in a rainwater pond. The domestic sewage of 73 apartments in this pilot project is pumped from a collector pit outside the building into a root zone treatment plant for biological treatment. Research on the performance of the treatment plant has shown a reduction in the pollution load to below the standards of bathing water quality (of the EC), as well as successful reuse of the effluent for irrigation and toilet flushing. This project has received an award from the President of the Federal Republic of Germany in a national competition. (Landscape Architect: H. Loidl)
StormWater Harvesting and Reuse Projects in Germany
The Design of Zero Runoff Settlement
(2) Project Berliner Straße 88, Berlin-Zehlendorf
In 1992 the construction of project Berliner Straße 88 was begun. The storm water from 160 housing units is collected in three cisterns making up a total storage capacity of 650 m³. The water is then reused for irrigation. The runoff is discharge into an artificial water course and a storm water pond of 1.000 m² (1.500 m³, max, depth 3 m). The pond water is recycled through the water course by solar and wind energy and continuously cleaned in a root zone treatment plant (the water percolates horizontally to the rootzone of a 1 m depth reed bed). The excess water is infiltrated through ground water recharge units. No storm water leaves the premises. (Landscape Architect: U. Grünberg)
(3) Project “Teltow-Mühlendorf”
This project area is 29 ha, comprising 1.800 housing units. (Architect: Zeidler Roberts Partnership)
Terrain Modelling
This newly developed concept assumes that all of the storm water and the necessary excavation is to stay on the project site. Using the displaced earth (250 000 m³), the terrain has been modelled so that the surface water can be diverted to a centrally located pond, resulting in a rise of about 1 m in the ground level in the centre of the project. A considerable environmental stress has been prevented by not hauling away the excavated earth, which would have require approx. 25 000 truck loads.
Storm Water Disposal for Traffic Ways
The major goal of this design is to minimise the interference of the natural water regime within the project area. In spite of the high percentage of paved and otherwise sealed areas, the precipitation remains within the boundaries of the project. The storm water runoff from sidewalks, bicycle paths, parking lanes, pedestrian walkways, green areas and playgrounds is conveyed to the subsoil through local infiltration. The runoff from the streets is intercepted in lateral gutters and conveyed to three storm water purification facilities and, after being extensively biologically treated, fed to a central storm water pond. Surplus storm water is infiltrated when complete filling of the pond forces water over the edge into infiltration trenches located in the banks. The overflow is also biologically treated prior to the infiltration in vegetated filters.
Storm Water Disposal on Residential Lots
The precipitation from all rooftops is stored in cisterns and from there made available to the residents to be used as non-potable water substitution. The surplus water is to be led to infiltration trenches. The pond water will be circulated through four natural-looking channels (flowing brooks), which run through the residential areas. The resulting cooling effect on the immediate surroundings, as well as the enhancement of the living conditions through simultaneous aeration of the lake, are the primary goals of the design concept.
(4) Project “Former Airfield Böblingen-Sindelfingen”
In this 85 ha project, the entire storm water runoff is proposed to be collected, treated and reused as a substitute for drinking water used in recreation, irrigation, toilet flushing, washing machines and still further uses where drinking water quality is not required. The excess water is discharged to a river bed.
The basic aim here is that all of the storm water will be reused within the project area. (Architect: Mory Osterwalder Vielmo, Landscape Architect: Kienle)
(5) Project “ Südlicher Mittelpfad” MTC DaimlerChrysler AG
In the city of Sindelfingen 40.000 people are employed by DaimlerChrysler AG to produce 4.000 cars daily. In the Mercedes-Benz-Technology-Centre (MTC) 6.500 designers and technicians are working on the development of new cars. The company plans to expand the MTC over an area of 26,9 ha including the construction of new buildings with 250.000 m² floor area and to employ up to 4.000 new staff. Based on the Town Development Plan designed by the architects Mory Osterwalder Vielmo and the landscape architect Kienle only 9,4 ha will be built-up and the remaining 17,5 ha will be a landscaped park.
It is proposed to undertake the following ecological measures that include the harvesting of the entire runoff from the roads, yards and roofs, including a major public road, treating it with natural treatment methods and to create a new large lake of 1 ha in the proposed park. The surplus of treated water shall be pumped over a hill to feed a drying riverlet.
The present design of Ecological Sanitation
(6) Project “International City of Auroville”, India
The International City of Auroville is designed by the French Architect Roger Anger. This township is to inhabit 50.000 people within a circular area with a diameter of 2,5 km, and be surrounded by a 1,25 km wide greenbelt.
The geographic centre of the township is located on a gentle hill, 52 m above sea level, 5 km from the coast of the Andaman Sea, and 200 km south of Madras. When the first settlers arrived, the hill was devastated by centuries of deforestation. Huge gullies had been caved out. The land had been cleared and the red earth was exposed to the torrential monsoon rains. The construction of Auroville began in the centre, which is to be created into a park with a spherical building, 30 m in diameter, an amphitheatre, and an old banian tree surrounded by a large lake. In the early 1970’s, the place was not fit for human life, with no shade and no water.
The first settlers had to control the erosion by “bunding” and reforestation, as well as provide the basic infrastructure and water supply. This has just recently been achieved. In the meantime, the population in the surrounding areas has grown, along with their ability to extract groundwater.
Since the early 1990’s, sea water intrusion into the coastal aquifers has been reported.
Under this threat, an alternative water management scheme was developed by the author in 1992 in order to safeguard the very existence of the city. It is planned to base the entire water supply on the precipitation. The rain water is to be harvested from the roofs and stored in cisterns. The remaining surface runoff, including that from the roads, is to be captured and stored in large reservoirs within the greenbelt. After purification, it will be lifted up to the large central lake. After further purification in the lake, the overflow will be infiltrated beneath the park into the first aquifer which lies above sea level. From there, the water can be tapped by wells throughout the city. The harvested storm water is not sufficient to meet the full demand for irrigation.
Therefore, the entire waste water has to be treated to meet bathing water quality standards and reused for the irrigation of agricultural lands within the greenbelt.
(7) Project “Beijing Olympic Green 2008”
This project was an International Competition for conceptual planning and design of the Beijing Olympic Green 2008. Architects:HWP Planungsgesellschaft mbH, Kienle Planungsgesellschaft Freiraum und Städtebau mbH. The Olympic Site conserves an area of 1.233 ha. It includes the Olympic Area, the Olympic Village and the Olympic Park. The Olympic Park conserves an area of 540 ha. Part of the Olympic Park is the Olympic Lake with a surface of 150 ha and a Forrest belt of 320 ha. The ecological concept aims for a favourable microclimate and includes a rainwater and wastewater management concept. The Olympic Lake is entirely fed by a rainwater harvesting system. Water management, energy supply and traffic are following the most modern concept.
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| IBA Block 6 Berlin-Kreuzberg | Berliner Str. 88, Berlin Zehlendorf |
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| Former Airfield Böblingen-Sindelfingen | Teltow-Mühlendorf, near Berlin |
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| "Südlicher Mittelpfad" MTC DaimlerCrysler AG | Auroville - India |