pacted by runoff (drinking water, recreation, fisheries and other aquatic life, agriculture, industrial water supplies, and groundwater supplies); and the balance of his paper describes forms and degrees of impacts on each user type.
The compelling physical difference between storm runoff and all other discharges of waste liquids to streams and other receiving waters (lakes, bays, estuaries, and groundwater) is the high-volume, short-duration, intense pulse nature of the phenomenon--followed often by prolonged periods of little or no discharge at all. Storm runoff, therefore, represents a shock load to any receiving water, to the plants and creatures who live there, and to the human beneficiary groups awaiting and expecting a reliable source of usable water downstream.
The quality impacts of runoff, which can be both acute and chronic, appear to result most often and widely from "high concentrations of toxic compounds, heavy metals, and petrochemical compounds; high BOD [biochemical oxygen demand] loadings leading to decreased oxygen concentrations; increased turbidity; and synergistic interactions of two or more of these factors." Closings by public health officials of lake, estuarine, and ocean-bay beaches resulting from elevated coliform bacteria counts in storm runoff, while somewhat less dire consequences, are nonetheless universally routine. "Singin' in the Rain" appears to be the one positive, uplifting benefit of the experience.
From their normally dispassionate, just-the-physics, Ma'am viewpoint, engineers have tended to confront runoff with a statistical and natural-history perspective suggesting that coping with it is almost hopeless. It occurs in too large events. It is too transitory. It is too unpredictable. And it is too powerful. In addition to glaciation, earthquakes, freezing and thawing, and simple gravity, there is only one phenomenon that makes the earth smoother than a billiard ball, viewed from wh...