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TO: Mayor and City Council <br />FROM: Mark Bernhardson, City AdministratoY' <br />DATE: October. 31, 1985 <br />SUBJECT: Gregory Wetlands Alteration <br />BACKGROUND <br />The proposes: development on the Gregory property design includes: <br />a) placement of a decorative pond in an area that currently does <br />not function as a wetland, serving only as a retention area; <br />b) the dredging of a designated wetland to improve initially the <br />aesthetic aspects of the wetland with the creation of a wildlife <br />pond. Approval has been given for the decorative pond. <br />The dredging of the designated wetland involves the removal of 5,000 <br />cubic yards of spoils, most .f which would probably be transported off <br />site, hopefully into a farm area as replacement top soil. In order to <br />accomplish this it would require both a conditional use permit and a <br />variance under Orono's code. <br />The size of the existing wetland that is intended to be altered is <br />approximately 2.6 acres and serves a watershed for drainage of <br />something under 100 acres. The area to be dredged consists of 1.3 <br />acres. Presently the pond is drained by an inverted culvert under <br />County Road 15 which is 1.3 feet lower at the intake than at the <br />outflow to Lake Minnetonka. In consideration of the sma 11 size and <br />type of watershed that is served by this pond, f low to the lake out of <br />this area is almost exclusively from the snow melt spring run-off with <br />outf low at other times only during heavy rains when the pond is at its <br />capacity. <br />Given the fact the end of the culvert sits a foot above the ordinary <br />high water mark of Lake Minnetonka there is very little back flow from <br />the lake into the pond. It is suspected that there is however <br />communication between the lake and the we�.lands and the proposed <br />decorative pond area through the ground water system which may be <br />considerably greater than any flow to the lake from the pond. <br />Existing vegetation in this very mature wetland has gone beyond normal <br />grasses, cattails etc_. into woods, principally the willow variety. <br />ISSUES <br />Primary environmental purposes served by such wet Iands are: <br />- Storm water ponding or retention <br />- Settlement area <br />Sediment trap <br />Nutrient trap <br />- Wildlife habitat <br />PROPOSAL <br />As mentioned the a 1. terat ion of the we t lands invo 1 ves the approximate <br />1 <br />