Watershed-Based Optimal Stormwater Management: Part 1—Application of StormWISE to Little Crum Creek in Suburban Philadelphia

Municipal stormwater regulations are inadequate to achieve water quality goals in impaired urban watersheds receiving stormwater runoff, especially in states where municipalities have autonomy in developing and enforcing stormwater ordinances. A watershed-based approach to improving the quality of impaired streams can be very difficult to develop and implement when a stream drains multiple adjacent communities. This paper describes a watershed model, called StormWISE, that identifies optimal combinations of stormwater best management practices (BMP's) and retrofit low impact development (LID), and its application in developing an "action plan" for the impaired Little Crum Creek watershed in suburban Philadelphia. StormWISE results have improved the prospects for acceptance of the plan by the four municipalities whose storm sewers drain to the stream because of the model's focus on cost minimization and its ability to prioritize investments.