08-23-1999 Council Packet - Laserfiche WebLink

Home Browse Search

•l WlAn - George Stickney June 25,1999 Page 2 Review of Various Topics Stormwater Pond on Lot 2 A stormwater pond will be established on Lot 2 behind ^e existing residence. This pond will treat a majority of the added runoff caused by the hew private road. Due to topography of the site, runoff from most of the new residences cannot be collecetd in a single pond on site, hence vegetated buffer strips will be preserved within each lot for stormwrater quality enhancement. Stormwater Ponding in Wetland Adjacent to Luce Line A1.6 acre wetland in Lots 5 and 6 adjacent to the Luce Line, is the receiving body for most runoff from the site. This wetland outlets under the Luce Line via an old 36 ” culvert. The draft Orono Stormwater Plan indicates this should be reduced to 18” diameter to protect downstream properties. Applicant has agreed to do this and has submitted a preliminary design plan, subject to DNR approval. This plan will result in a slight increase in the wetland elevation at times, and this is a concern of the DNR as it could inundate the horse trail next to the Luce Line. Applicant proposes to raise the horse trail with fill, which has received a conceptual approval from DNR subject to acceptable design details. DNR also requests that the City be responsible for maintenance of the drainage struf'tures, even though we may require the homeowners association to maintain them. Tbb is an item for discussion. The 18” culvert will raise the 100-year flood elevation to just above 966', which could have a minor temporary impact on two septic sites unless a low berm or other measures are established. This will have to be detailed prior to final plat approval. Wetland Designation The City has received a wetland delineation report and has concluded that all wetlands delineated along the Luce Line by applicant's consultant, are part of the designated City wetland and wall not be creditable as dry buildable. This has resulted in some adjustments of fhe road location and a few lot lines, but has not impacted drainfield sites. However, filling the horse trail wall likely result in filling of a small portion of the wetland adjacent to the trail, as will the establisliment of the new outlet stmcture. Staff recommends that a variance be granted for this minor filling of wetland, subject to appro /al of the appropriate agencies. Road Layout As a result of the wetland designations, the road layout has shifted slightly northward in a somewhat tighter curve than code allows. Staff is recommending a variance to allow curve radii of 225' at the west end and 200' near the mid point of the road where 275' would normally be required for a 30 mph design private road. This variance is justified because this is a short cul-de-sac serving only 8 homes, with no future potential to be a through road.