|Construction activities that disturb one acre or more of land, and construction on smaller sites that are part of a larger project, must comply with a Construction General Permit that regulates storm water leaving construction sites. Site owners must notify the state, prepare and implement a Stormwater Pollution Prevention Plan (SWPPP), and monitor the effectiveness of the plan. The plan, which must also address control of polluntants in stormwater post-construction, must be submitted to the Water Board's SMARTS electronic database and must be on site and available to inspectors.
Each discharger must certify annually that construction activities are in compliance with the requirements of the General Permit and the SWPPP.
Construction activities that maintain existing facilities, and do not involve a change in grade, are not required to be covered under the general permit.
Special Responsibilities Due to Mercury Mines
At construction sites located in the vicinity or downstream of a historical mercury mine, soils may contain mercury, a neuro-toxin that threatens humans and wildlife. Mercury must therefore be included in the assessment of potential pollutant sources and the discharger may need to employ more robust and redundant erosion and sediment controls than are normally used at similar construction sites. To assist you in identifying if your site may be located in the vicinity or downstream of a historical mercury mine, maps of historical mercury mines in the San Francisco Bay Region are available at the links below. The pink triangles on the maps indicate approximate locations of historical mercury mines and areas shaded in red indicate approximate runoff flow paths. These maps are listed by county: