12-11-2000 Council Packet - Laserfiche WebLink

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Site Group 7". The soils in Group 7 have ^'moderate limitations for residential and commercial development with public sewer systems where slopes are less than 12%. In areas where slopes are more than 12%, these soils generally have severe limitations jor commercial and residential development because of the high cost of installing utilities and grading streets and building sites. Proper design of buildings, site planning, and minimal grading reduce erosion and sedimentation. Where slopes are more than 18%, these soils are better suited to uses that enhance the natural beauty of the area than to most other uses The proposed development has been designed with these limitations in mind. It is also noted that the property does not meet the slope criteria for being considered as a bluff area under the Shoreland regulations, and is not subject to bluff impact zone limitations. The following aspects of the Development are intended to minimize oreliminate erosion and stormwater runoff water quality concerns: a.A majority of the slopes in excess of 18% on Lots 2 and 3 will not be disturbed by grading and will have existing vegetation retained. These sloped areas will be protected from excess runoff by a swale which will direct runoff to the proposed retention pond on Lot 1 above the southeasterly ravine. Easements and covenants will be put in place to ensure the swale will be retained and maintained on a permanent basis. b. c. The proposed retention pond on Lot 1 will result in a decrease of the runoff flow rates within the southeast ravine. Due to the steep gradient of the existing ravine, the watershed area tributary to this ravine has been reduced significantly and redirected to the northerly stormwater pond, thereby decreasing the runoff rates and volumes reaching the southeast ravine to a level lower than pre-development conditions. The pond in Lot 1 will also serve as a water quality pond, meeting NURP standards for sediment and nutrient removals prior to discharge to the ravine. Also, because the southeast ravine has steep bank slopes, the protected area where no grading is allowed will encompass the entire ravine area within Lot 2. In order to eliminate disturbance of the steeper slopes on Lots 2 and 3, installation of sanitary sewer along the common lot line as well as within Wildhurst Trail vvill be via directional boring methods to avoid open cuts which would potentially affect slope stability. Page 3 of8