Evaluation of Variability in Response to the NPDES Phase II Stormwater Program in Virginia

Abstract

AbstractAuthorities of municipal separate storm sewer systems (MS4s) in small urbanized areas (population less than 100,000) are required to implement stormwater control measures (SCMs) to mitigate and reduce the impacts of urbanization on stormwater runoff under Phase II of the National Pollutant Discharge Elimination System’s (NPDES) stormwater program. This 16–year-old policy has been challenged in its effectiveness in maintaining or improving water quality, but reviews are scarce because of the policy’s subjective requirements, and because it governs MS4s across a wide variety of characteristics, objectives, and institutional capacity. This research models SCM selection as a function of these differences, thereby systematically evaluating the policy’s outcome in its constituents. The results show that certain characteristics of an MS4 community significantly affect the selection of SCMs, suggesting that regulations may need to be refined to address distinct groups of MS4s. The results also reveal inef...