Stormwater Studies

Runoff is a natural hydrologic process that is strongly influenced by land use.  Runoff from rainfall or melted snow has three possible short-term routes:  it can run off the land surface, percolate to the groundwater reservoir or go into storage on or near the surface.  Urbanization of a watershed, such as paving of roads and installation of drainage systems, can result in increased surface runoff rates. Stormwater drains relieve localized flooding but contribute a higher velocity and volume of runoff downstream.  The quality of stormwater runoff from urban areas is of vital concern when a waterbody is located nearby.  Runoff can carry oil and gasoline from vehicles, leaves, soil, lawn chemicals and fertilizers.  Potential contaminants are washed into streams and lakes in sufficient concentrations to degrade the water quality of the receiving body of water.

The relationship between storm characteristics and water quality must be calculated before a pollution-control program can be developed.  For studies of stormwater runoff the determination of water quality of constituent load between different storms at different locations within the watershed are compared.  Total load per unit area, such as pounds per acre-inch per year of a particular constituent, has been used for long-term comparisons.