CCP 08-21-2000 - Laserfiche WebLink

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. . . should be installed as close to Lake Josephine as possible to retain the maximum amount of IUnnoff (thereby increasing water quality). A pedestrian crossing should be incorporated into the channel improvements eonnecting Fernwood Court and Ingerson Court (this could be incorporated into a weir, bridge or culvert crossing. Landscaping should be included with the channel improvements including trees, shrubs and natural grasseslflowers etc. B. HamlinefTH 51 area Staff recommends that some permanent ponding be created in this area in order to improve the waler quality of runoff generated from the Tiller Lane storm sewer system, TH 51 and the western end of Ingerson Road. The ponding improvements should be in the form of expanded channels with weirs to retain water (in lieu of one large pond) prior to releasing it from the neighborhood. The channels should be regraded to look as natural as possible. A significant portion of this area is privately owned and would not be available for ponding unless the City acquires drainage easement rights or fee title to the property. The existing wetland between Tiller Lane and Ingerson Road could be modified to include a small peninsula on the west side to create better circulation of runoff through the wetland. A pedestrian/bike trail should be included in this area to connect Ingerson Road and Tiller Lane. Landscaping should be included to give the area a more natural look. Removal of existing trees should be minimized in the area and the existing screening effect of the trees along Hamline A venue should be maintained and enhanced where possible. C. Rain Gardens During the course of the lask force meetings, the feasibility of incorporating of rain gardens into the project was investigated. Rain gardens are small depressions (planted with shrubs and flowers etc.) adjacent to the roadway which are intended to capture runoff from very small areas (typically a single lot and the adjacent street) and allow that runoff to seep into the ground in lieu of colleeting it in storm sewers. Rain gardens are excellent for enhancing water quality and theoretically reduce the size of storm sewers and regional ponding in a given area. In order to be most effective, the gardens should be constructed in several lots in a gi ven area and best results occur with granular subsoils which promotes a high amount of infiltration. Three areas were identified within the project area as possible loeations for rain gardens due to the relatively flat terrain in these areas. The areas identified are Ingerson Road west of Fernwood Street, the low area of Carlton Drive (approximately 4 lots), and the stretch of Harnline Avenue south of Ingerson Road (approximately 6 lots). Although these areas have been identified based upon the flatness of the existing terrain a number of additional factors must be considered before proceeding with rain gardens. Resident Approval Conflicts with driveways Conflicts with water services Confli cts with trees Gardens should not span over property lines (two owners would need to approve) Reduction of soil cover over watermain (requires insulation) Reduction of soil cover over sanitary sewer (requires insulation) Conflicts/impacts to underground utilities NSP, US West, Media One etc.