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Page 21 of 26 <br />Permit No: MN R100001 <br />after the area is no longer actively being worked. All other slopes that have a continuous <br />positive slope to a special water must have temporary erosion protection or permanent <br />cover within 7 days after the area is no longer actively being worked. <br />b. Temporary sediment basin requirements described in Part Ill. B.1-5 must be used for common <br />drainage locations that serve an area with five (5) or more acres disturbed at one time. <br />2. Post construction.' The water quality volume that must be treated by the project's permanent <br />storm water management system described in Part III.C. shall be one (1) inch of runoff from the <br />new impervious surfaces created by the project. <br />Buffer zone. An undisturbed buffer zone of not less than 100 linear feet from the special water <br />(not including tributaries) shall be maintained at all times. Exceptions from this requirement for <br />areas, such as water crossings or limited water access, are allowed if the Permittee fully <br />documents in the SWPPP the circumstances and reasons that the buffer encroachment is <br />necessary. All potential water quality, scenic and other environmental impacts of these <br />exceptions must be minimized and documented in the SWPPP for the project. <br />4. Enhanced runoff controls. The permanent storm water management system must be designed <br />such that the pre and post project runoff rate and volume from the 1, and 2 -year 24-hour <br />precipitation events remains the same. <br />Temperature Controls. The permanent storm water management system must be designed such <br />that the discharge from the project will minimize any increase in the temperature of trout stream <br />receiving waters resulting from the 1, and 2 -year 24-hour precipitation events. This includes all <br />tributaries of designated trout streams within the section that the trout stream is located. Projects <br />that discharge to trout streams must minimize the impact using one or more of the following <br />measures, in order of preference: <br />a. Minimize new impervious surfaces. <br />b. Minimize the discharge from connected impervious surfaces by discharging to vegetated <br />areas, or grass swales, and through the use of other non-structural controls. <br />c. Infiltration or evapotranspiration of runoff in excess of pre -project conditions (up to the 2 - <br />year 24-hour precipitation event). <br />d. If ponding is used, the design must include an appropriate combination of measures such as <br />shading, filtered bottom withdrawal, vegetated swale discharges or constructed wetland <br />treatment cells that will limit temperature increases. The pond should be designed to draw <br />down in 24 hours or less. <br />e. Other methods that will minimize any increase in the temperature of the trout stream. <br />D. REQUIREMENTS FOR DISCHARGING TO WETLANDS <br />If the project has any storm water discharges with the potential for significant adverse impacts to a <br />wetland (e.g., conversion of a natural wetland to a storm water pond) , the Permittee(s) must <br />demonstrate that the wetland mitigative sequence has been followed in accordance with D.1 or D.2 of <br />this appendix. <br />1. If the potential adverse impacts to a wetland on a specific project site have been addressed by <br />permits or other approvals from an official statewide program (U.S. Army Corps of Engineers <br />404 program, Minnesota Department of Natural Resources, or the State of Minnesota Wetland <br />wq-strm2-51 <br />