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<br />www.pca.state.mn.us • 651-296-6300 • 800-657-3864 • Use your preferred relay service • Available in alternative formats <br />wq-strm2-47 • 9/27/18 Page 7 of 11 <br />Yes N/A Permanent stormwater treatment system (continued): <br /> Outside of an ERA within a DWSMA <br />classified as having high or very high <br />vulnerability unless a regulated MS4 <br />Permittee has performed or approved a <br />higher level of engineering review <br /> Areas where soil infiltration rates are <br /> field measured at more than 8.3 inches per <br />hour unless soils are amended to slow the <br />infiltration rate below 8.3 inches per hour <br /> If infiltration is prohibited: <br />Yes N/A <br /> Other methods of volume reduction are <br />considered <br /> The water quality volume is treated by a <br />wet sedimentation basin, filtration system, <br />regional ponding or equivalent methods <br />prior to the discharge of stormwater to <br />surface waters. <br /> If proximity to bedrock precludes the installation of any <br />of the permanent stormwater management practices, <br />some treatment has been provided: <br />Yes N/A <br /> Grassed swales <br /> Smaller ponds <br /> Grit chambers <br /> <br /> Notes <br /> <br /> <br />Yes N/A Permanent treatment method selected: <br /> Infiltration (e.g., infiltration basins, infiltration trenches, <br />rain gardens, swales with check dams, natural <br />depressions) <br />Yes N/A <br /> Include at least one soil boring, test pit or <br />infiltrometer test in the location of the <br />infiltration practice <br /> If the infiltration rate has been field- <br />measured, the rate has been divided by <br />two for design purposes <br /> Appropriate testing has been conducted to <br />ensure a minimum of three feet of <br />separation from the bottom of the infiltration <br />practice to the seasonally saturated soils <br />and/or bedrock <br /> The system has been designed to maintain <br />pre-existing hydrologic conditions of <br />wetlands in the vicinity (e.g., do not breach <br />a perched water table that is supporting a <br />wetland) <br /> The SWPPP includes requirements to <br />avoid excavating the infiltration system <br />within three feet of final grade before the <br />drainage area is stabilized <br /> If the infiltration system is excavated within <br />three feet of final grade, rigorous erosion <br />prevention and sediment control BMPs are <br />used to keep all runoff and sediment out of <br />the infiltration system <br /> <br /> Notes <br />