City updates some storm water rules for developers in valley
November 15, 2011
City leaders have changed development rules for storm water in areas along the valley floor.
Under the revised code, developers do not need to build additional storm water detention ponds and facilities if removing impervious areas — such as buildings or pavement — is part of redevelopment. The earlier code required extra storm water detention for all redevelopment, so runoff matched predeveloped conditions.
City Council members acted after a consultant’s study determined the drainage systems in question — Tributary 0170, Pickering Ditch and East Lake Sammamish Tributary — remained stable and requiring additional storm water detention is not likely to benefit fish habitat.
The state Department of Ecology agreed, and allowed the city to make the exception.
Developers must still build storm water detention facilities for all impervious surfaces added in new construction. In addition, the requirements for storm water treatment for water quality remain the same.