ABSTRACT
The storm drainage system carries runoff from the roofs of buildings, street paving, and other ground surfaces, to an outfall into a natural channel. The location and timing of waterway crossings has therefore had a very strong influence on the spatial form and evolution of many cities. Underground utilities are laid out to make as few stream crossings as possible because of water infiltration difficulties, the high cost of underwater construction, and the difficulties inherent in insulating utility lines carried across bridges. The system of interaction results in concentrations of urban development in floodable areas that are subject to immense flood damages in terms of both dollars and human lives. Vegetation retards the flow of water over the surface of the ground and makes the ground more absorbent by opening up the soil through root growth. A number of state agencies keep good hydrologic data, especially those agencies concerned with water resources and flood control.
