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DRAFT IV. STORMWATER MANAGEMENT STUDY The College's environment is largely a function of its two lakes, Johanna and Little Johanna, along with ponds and wetlands which occupy a large part of the total land area of ~h.... .......................,,,... D......fh 1.....1.,......... "'I"...... ;rt^htif,......rt .....'" ;,....,,..,....,i...orl h" tho. f\"-;nnoC>At-:l D......lll,ti"n r......ntrr.J 1I11:,:i I.JClII It-JU':>. UV~11 IClr\.C;v C1lv IUc;lll111'JU UV Ilj,!-";.HI'-'U u1 ..,...... IY,"''''''''',",V<<.'' I VIIU"V" ,"-,v,n,vl Agency (MPCA). Both lakes are also included on the MPCA's March 31, 2004, proposed Total Maximum Daily Load (TMDL) list. The TMDL list serves as a comprehensive source of streams and lakes that are not meeting their designated uses because of excess pollutants. Furthermore, Lake Johanna is classified as eutrophic, meaning that is has waters rich in mineral and organic nutrients that promote a proliferation of plant life, especially algae, which reduces the dissolved oxygen content and often causes the extinction of other organisms. Lake Johanna also exhibits water levels from a high of 881.27 feet on July 3, 1978, to 870.35 feet on July 21, 1926, or a range of 10.92 feet, and its Ordinary High Water Leve[ is 878 feet. Littie Lake Johanna has very little published information. This Plan presents a campus-wide Stormwater Management strategy that identifies Best Management Practices (BMPs) that can be implemented to facilitate the campus redevelopment. This Plan's overall goal is to cooperate with appropriate agencies including the Cities of Roseville and Arden HiI[s, Rice Creek Watershed District (RCWD), and the Minnesota Pollution Control Agency to improve the quality of both of the campus lakes. Achievement of these goals will deliver good quality stormwater runoff from the campus to lakes and wetlands at acceptable rates and volumes, whiie reducing pollutant and sediment loadings, bank erosion, and water quality degradation. I --i --, Stormwater quality improvement BMPs that seem particularly appropriate for the campus include: wet detention ponds; pollution prevention such as material storage control, turf management, parking lot cleaning; pervious pavements to reduce the amount of runoff; green roofs, which can reduce impervious areas on top of structures like parking ramps; infiltration practices and filter devices which primarily trap solids that have pollutants attached to them. In some respects, the implementation of the Plan described in this document will resemble a Stormwater Pollution Prevention Plan (SWPPP) that the National Pollutant Discharge Northwestern College Master Plan PUD Application Report 9 13529.000