Caltrans Storm Water Management Program: Overview of New Requirements Driving the Implementation of Structural BMPs

The California Department of Transportation (Caltrans) constructs, operates, and maintains the state highway system in California. Stormwater runoff from Caltrans construction sites and roadways is subject to the federal Clean Water Act and its associated NPDES permit program. Caltrans began implementing a Statewide Storm Water Management Plan (SWMP) in 1996. In conformance with EPA directives, Caltrans control efforts have focussed on "best management practices" (BMPs) to control sources of pollutants in storm water. For the most part, BMPs consist of common sense pollution prevention techniques rather than use of structural treatment facilities. The same approach, using non-structural controls, has also been applied to urban runoff from large regulated municipalities and runoff from construction sites. During 1999, the regulatory climate for storm water management in California changed dramatically. New permit requirements will require methods that achieve higher levels of pollutant control than are achieved by conventional BMPs. The statewide storm water permit recently issued to Caltrans, as well as other recently issued municipal permits, require that storm water discharges comply with established water quality standards. Compliance with these standards is a significantly more stringent requirement than was previously applied to these discharges. Also, limited information is available regarding the technology and other controls that can be used to meet these more stringent requirements. Caltrans has modified its Storm Water Management Plan to incorporate this new goal. In addition, Caltrans has initiated an extensive research and pilot-testing program to identify technologies that can be used to meet water quality standards.