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SECTION V <br />STRATEGY: REGULATION <br />No. <br />Policy <br />Tar et Audience <br />2. <br />In the design and construction of all new stormwater conveyance <br />City, Developers <br />systems and modifications to existing stormwater conveyance <br />systems, pretreatment of stormwater runoff to Nationwide Urban <br />Runoff Program (NURP) recommendations will be required prior to <br />discharge where feasible and practical to do so. These NURP <br />recommendations (Walker, 1987) include the following: <br />a. A permanent pool ("dead storage") volume below the principal <br />spillway (normal outlet) which shall be greater than or equal to <br />the runoff from a two point five inch (2.5") storm over the entire <br />contributing drainage area assuming full development. <br />b. A permanent pool average depth (basin volume/basin area) <br />which shall be equal to or over four feet (<_ 4'), with a maximum <br />depth of equal to or less than ten feet (< 10'). <br />c. An emergency spillway (emergency outlet) adequate to control <br />the 100 -year critical duration rainfall event. <br />d. Basin side slopes above the normal water level should be no <br />steeper than four to one (4:1), and preferably flatter. A basin <br />shelf with a minimum width of ten feet (10') and one foot (1') <br />deep below the normal water level is recommended to enhance <br />wildlife habitat, reduce potential safety hazards, and improve <br />access for long-term maintenance. <br />e. To prevent short-circuiting, the distance between major inlets <br />and the normal outlet shall be maximized. <br />f. Retardance of peak discharges for the more frequent storms <br />can be achieved through a principal spillway design which may <br />include a perforated vertical riser, small orifice retention outlet, <br />or compound weir. <br />Figure 15 in Appendix C shows those areas of the City which <br />drain to basins which meet the NURP treatment <br />recommendations prior to water being discharged across <br />municipal boundaries. <br />3 <br />The City of St. Anthony will sweep the streets at least five times <br />City <br />annually. Furthermore, future purchases of street sweeping units <br />will give consideration to street sweepers which have the greatest <br />ability to remove nutrients from the streets within the community. <br />City of St. Anthony Section V — Page 5 <br />WSB Project No. 1626-25 <br />August 2007 <br />33 <br />