2018-03-26-minutes-public-works-study-session

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Easlern Washington Phase 11 Alunicipal Stormicater Permit must include a summary of the project information used in calculating the project's rainfall erosivity factor (see #2 above) and a certified statement that: • The operator will comply with applicable local stormwater requirements; and • The operator will implement appropriate erosion and sediment control BMPs to prevent violations of water quality standards. Core Element #3: Source Control of Pollution Reauirements All new development and redevelopment projects meeting the regulatory threshold shall apply all known, available and reasonable source control BMPs. Operational and structural source control BMPs shall be selected, designed, and maintained according to Chapter 8 of the Stormwater Management Manual for Eastern Washington (2004) or another technical stormwater manual approved by the Department. Core Element #4: Preservation of Natural Drainage Systems Reouirements All new development and redevelopment projects meeting the regulatory threshold must preserve natural drainage systems to the extent possible at the site. The manner by which runoff is discharged from the project site must not cause a significant adverse impact to downstream receiving waters and down -gradient properties and should be addressed as part of the off-site analysis described in Appendix 3A of the Stormwater Management Manual for Eastern Washington (2004). All outfalls must address energy dissipation as necessary. A project proponent who believes that energy dissipation should not be required for a new outfall must provide justification in the project's stormwater site plan or drainage study report. Core Element #5: Runoff Treatment Ren uirements Runoff treatment is required for projects meeting the regulatory threshold when the technical thresholds/requirements below for Basic Treatment, Metals Treatment, Oil Treatment, or Phosphorus Treatment are met. Treatment facilities shall be selected, designed, sized, constructed, operated and maintained in accordance with this Core Element and the guidance in Chapters 4 and 5 of the Stormwater Management Manual for Eastern Washington (2004), or another technical stormwater manual approved by the Department. All Permittees must require runoff treatment facilities to be sized for the applicable design storm(s) described in this section: each jurisdiction must identify a preferred method or methods for sizing treatment facilities or provide alternative guidance. All runoff treatment facilities must be sized for the entire flow that is directed to them. Appendix 1- Minimum Technical Requirements Eastern Washington Phase II Municipal Stormwater Permit —August 1, 2014 Page 10