ABSTRACT
Performance of stormwater infiltration in a given site development is defined by the objectives of the project, as it is in any other human endeavor. Meaningful stormwater management objectives must be founded on an understanding of specific conditions both within the limits of the site and in the larger landscape systems of which on-site phenomena are part, including surrounding urban neighborhoods, upstream and downstream watersheds and underlying landforms and soils. In some regions, rainstorms tend to be separated by a few days or more. Infiltration basins tend to concentrate the contaminants from their drainage areas onto small soil areas and to trap them there. Suspended sediment is probably the most common urban runoff pollutant. Soil particles originate on construction sites, and in drainage swales and stream channels eroding in response to stressful pulses of urban stormwater. All surface waters and surface soils contain large, active populations of bacteria, fungi and other organisms that exist on supplies of organic material.
