Stormwater & Water Pollution Control

On July 15, 1999, the SWRCB issued the "Order No. 99-06-DWQ, NPDES No.CAS000003, National Pollutant Discharge Elimination System (NPDES) Permit, Statewide Storm Water Permit and Waste Discharge Requirements (WDRs) for the State of California, Department of Transportation (Caltrans)"; hereby called the "Permit". The Permit regulates storm water discharges from Caltrans properties, facilities and activities, and requires that the Caltrans construction program comply with the requirements of the "State Water Resources Control Board (SWRCB) Order No. 99-08-DWQ, National Pollutant Discharge Elimination System (NPDES) General Permit No. CAS000002, Waste Discharge Requirements (WDRs) for Discharges of Storm Water Runoff Associated with Construction Activity (General Permit)" issued by the SWRCB, to regulate discharges from construction sites that disturb 5 acres (ac) or more.

Beginning March 10, 2003, U.S. Environmental Protection Agency (EPA) and SWRCB regulations will regulate discharges from projects with soil disturbance of 1 acre or more by amending the General Permit and thus including coverage of projects with soil disturbance of 1 acre or more.

Based on a petition challenging the General Permit, the provisions for monitoring, sampling and analysis were modified pursuant to a court order. The modified provisions were issued as Resolution No. 2001-046, "Modification of Water Quality Order 99-08-DWQ State Water Resources Control Board (SWRCB) National Pollutant Discharge Elimination System (NPDES) General Permit For Storm Water Discharges Associated With Construction Activity (General Permit)", adopted by the SWRCB on April 26, 2001. The modifications require permittees to implement specific sampling and analytical procedures to determine if BMPs implemented on a construction site are:

  • Preventing further impairment by sediment in storm waters discharged directly into waters listed as impaired (Clean Water Act Section 303(d) List [303(d) List]) for sediment, silt, or turbidity; and
  • Preventing other pollutants that are known or should be known by permittees to occur on construction sites and that can not be visually observed or detected in storm water discharges, from causing or contributing to exceedances of water quality objectives.

The Permit gives RWQCBs the option to specify additional requirements they may consider necessary to meet water quality standards. In addition, RWQCBs retain the authority to issue NPDES permits for individual projects or adopt Regional Permits. Copies of the Permit and the General Permit can be downloaded from the SWRCB Website.

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