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XXXXWESTWOOD PLANNING 81 ENGINEERING COMPANY <br />May 15, 1985 <br />.Jean 'fabusth <br />City of Orono <br />P.O. Box 66 <br />Crystal Bay, MN 55323 <br />RE: Gregory Residelice <br />Dear Ms. Mabusth: <br />ti <br />CITY <br />This letter is in response to a request for more information concerning the <br />proposed wetland alteration as we, along with Glenn Cook, discussed at our <br />most recent meeting. <br />1. Mr. and letrs. Gregory have indicated they will allow a qualified agent <br />of the City to periodically enter the property to observe and monitor <br />the condition of the wildlife pond after construction. <br />2. The grading plan for the wildlife pond area has been revised to show a <br />treated timber skimmer adjacent to the existing outlet culvert (to lake <br />Minneton a) and pond construction to allow a natural buffer/filtration <br />area of emergent vegetation (see attached detail). This combination <br />will help filte sediment and skim r,f algae and other suspended solids <br />and, according to Dick Hanson at the Gray Freshwater Biological <br />Institute and Joel Settles at the Hennepin Conversation District, will <br />improve the quality of water entering Lake Minrett�nka. The skimmer <br />desi n will be based on a storm frequency as determined by the City <br />Engineer. <br />3. The formal pond will be constructed in an a s�149 low area of about 3/4 <br />acre below the Lake Minnetonka H.W.L. of . The north portion has <br />heavy evergreen and deciduous tree cover to be retained. The southern <br />portion is covered by a drainage easement, has tree growth around the <br />periphery and grass cover within the center. This low point presently <br />accepts on and off -site runoff from about 2.6-3.0 acres which then <br />discharges into Lake Minnetonka by way of a culvert under County Road <br />15. The proposed grading will increase storm water storage 1`elow <br />elevation 931.5 by about 0.14 acre feet (0.44 t acre feet existing; O.SM2: <br />acre feet proposed). <br />This pond will be aerated with a fountain to reduce algae growth and <br />maintain good water quality. The steep pond side alopes will be <br />stabilized using 12 inches of heavy clay formed and pa^ked against the <br />natural sniff. As desired, the steep slopes and clay layer will prevent <br />the growth of emergent vegetation around the Cond edge. The out et <br />channel will allow emergent vegetation to become established and act as <br />a natural set iment filter for water 7Uawins'_ into the wildlife pond. <br />161S WAVIAIA SOUIEVANO. MINNEAV0I1S MINNESOTA S44I6 161It 5A6015% <br />