Requirements for Construction

As required by Provision C.3 of the Stormwater NPDES permit, The Contra Costa Clean Water Program has developed a Hydrograph Modification Plan (HMP) to ensure post-project runoff from Group 1 Projects shall not exceed estimated pre-project rates and/or duration, where increased runoff would result in increased potential for erosion or other adverse impacts to beneficial uses. As part of the HMP, an Infiltration Site Characterization Criteria and Guidance GIS Database was created to aid developers in the selection of appropriate runoff measures.


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