parking lot or other large paved area; an overflow storage system can 

 be incorporated to use part of the paved area as a detention basin [71]. 



4.12.5 Simulating Natural Systems 



In the natural system, water passes over vegetated land as overland 

 flow or through the soil in the groundwater. Pollutants are removed 

 biologically by microorganisms or plants; physically by filtration, 

 absorption, or deposition; and chemically by oxidation and other 

 reactions. Purification continues in streams and drainage-ways by the 

 same processes. Natural watercourses tend to meander through coastal 

 watersheds and floodplains, thus slowing the passage of water to the sea 

 and allowing greater opportunity for natural purification. Meandering 

 watercourses are also conducive to stream side vegetation, which aids 

 greatly in purification. 



The typical stormwater system has been designed to short-circuit the 

 natural process. Runoff water is diverted to drains, then to collection 

 pipes and trunks and finally to outlets that discharge into the nearest 

 watercourse. Natural purification by vegetation and soils is more 

 efficient and far less expensive than by artificial measures. 



A stormwater system that simulates the natural drainage system 

 has features to detain storm runoff and provides maximum soil infil- 

 tration for natural purification. The ideal way would be to pre- 

 serve and utilize existing natural drainages such as creeks, 

 sloughs, and swales, and to provide natural buffer strips along 

 the edges of all watercourses [116]. 



The Soil Conservation Service has summarized techniques available 

 for controlling runoff and thus simulating the natural rate of release 

 (Table 26). Although many of these techniques may be unsuitable for wide 

 application because they are experimental or do not fit local circumstances, 

 they suggest the variety of alternative solutions available. 



4.13 SOLID WASTE DISPOSAL - SUBPROJECT 13 



frPthis affluent country, each person consumes an average of 150 

 pounds of raw material every day, of which 130 pounds is in the form of 

 industrial products. Petroleum products and the factors of production 

 used by the petroleum industry account for a good deal of this industrial 

 consumption, and because much is eventually disposed of as solid waste 

 in landfills, this section highlights the location and design constraints 

 of landfills. 



4.13.1 Summary 



The major sources of waste may be lumped into three broad categories: 

 municipal waste, agricultural waste, and industrial waste. Municipal 



153 



