Caltrans Storm Water Quality Monitoring Program - Phase II Storm Drain System Inventory

Client: California Department of Transportation

Prime Contractor: Brown and Caldwell

Location: Central and Northern California

Period of Performance: June 2008 - Present

Project Description: Under its NPDES Phase II permit Caltrans is required to report the locations of all points of storm water runoff from Caltrans freeways, off-ramps, maintenance facilities, and other properties statewide. The Phase II Storm Drain System Inventory (SDSI) project is a large GIS-based field data collection effort being performed by Caltrans to meet these reporting requirements. The objective of the SDSI is to identify and describe point source stormwater features and their attributes as completely and accurately as possible. ADH is supporting Caltrans as a subcontractor to Brown and Caldwell with this Task Order by performing field investigations as described below.

ADH Responsibilities: During inventory of each stretch of highway or Caltrans facility, field teams identified and described discharge points, outfalls, inlets, BMPs and their respective terminal discharge areas (TDA). A variety of data sources, including as-built drawings, aerial photos and GIS datasets, were used to provide additional verification of feature locations. Field teams identified the area along Caltrans Right of Way where storm water leaves Caltrans property, establishing the discharge point for the TDA for each subject stretch of highway, and then identified the boundaries of the TDA itself. A field computer equipped with the Caltrans SDSI Data Collection Tool, Arc Map, and a Microsoft Access database application was employed to enter, store and manage the data collected, and to view aerial images and existing survey data. A GPS unit was incorporated with computer system and used to navigate and record the location of each inlet, outfall, BMP, discharge point and TDA. Using the GIS and GPS software, the attributes of each storm water feature/location visited (including digital photos, inventory information, GPS information, BMPs, and TDA boundaries) were digitally integrated into the aerial maps.

Identification of Storm Drain System Input

GIS Mapping of Storm Drain Details