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\\\\WESTWOOD PLANNING & ENGINEERING COMPANY <br />May 15, 1985 <br />Jean Mabusth <br />City of Orono <br />P.O. Box 66 <br />Crystal Bay, MN 55323 <br />- - - -. ■ I <br />l.-.I I <br />• I <br />RE: Gregory Residence SiTOEMc^o^ <br />Dear Ms. Mabusth: <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 Mrs. 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 />Minnetonka) and pond construction to allow a natural buffer/flltratlon <br />area of emergent vegetation (see attached detail). This combination <br />will help filter sediment and skim off 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 Minnetonka. ,The skimmer <br />desl>'n will be based on a storm frequency as determined by the City <br />Englnjer <br />3.ix^tj^g low area of about 3/AThe fjrmal pond will be constructed In an e <br />acre below the Lake Minnetonka H.W.L. of 93.' 'The north portion has <br />hea^'y 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-slte 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 below <br />elevation 931.5 by about O.IA acre feet (O.AA^acre feet existing; 0.58± <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 slopes will be <br />stablllxed using 12 Inches of heavy clay formed and packed against the <br />natural soil. As desired, the steep slopes and clay layer will prevent <br />the growth of emergent vegetation around the pond edge. The outlet <br />channel will allow emergent vegetation to become established and act as <br />a natural sediment filter for water flowlnv Into the wildlife pond. <br />74IS WAYZATA •OUKVARO. MiNNIAPOllS. MtNNtSOTA &S4M KITI SMOliS