Wherever sites are developed, the soil, plant and animal environment is invaded. Land erosion can be caused by neglect or lack of understanding of soil characteristics and grading techniques.
Development of sites increases runoff in streams in two ways. First, the amount of impervious area (roof tops, driveways, roadways, parking lots, etc.) is increased, preventing rainfall from infiltrating the ground, and resulting in direct runoff and increased surface flow. Secondly, storm sewers, gutters and so forth increase the efficiency and the speed of the runoff. This higher runoff produces greater stream discharge and velocity, and higher erosion force, creating an imbalance between the force of the stream and the ability of its own banks to contain it. It takes several years for a new balance to be developed. During this time of transition, other erosion problems can occur.