Caltrans District 7 Water Quality Volume Project

Client: California Department of Transportation	Prime Contractor: MACTEC
Location: Southern California	Period of Performance: July 2009 - January 2010

Project Description: ADH provided services in the identification of all watersheds and determination of the Water Quality Volume (WQV) for freeway and non-freeway corridor's Rights-of-Way in Caltrans District 7. This included Caltrans maintenance yards and rest areas situated in Los Angeles and Ventura Counties within the jurisdiction of the Los Angeles Regional Water Quality Control Board's (LARWQCB's). Per the Stipulation and Order Regarding the Corridor Stormwater Management Studies, ADH used as-built specifications of the impervious area that existed before and after December 1994. After being grouped by their respective watersheds, the as-built drawings were examined using a scalable image viewer, and dimensions were taken for various impervious roadway sections. Any increases in impervious areas that were added since 1994 were determined along these highway corridors and treated WQV's were calculated from these dimensions using a spreadsheet model.

ADH Responsibilities: ADH was responsible for the compilation of areas and WQV's from approximately 84 miles of highway, including sections of California Highways 2, 27, 66, 90, 107, 187, 213 in Los Angeles County and Highway 232 in Ventura County.