02-27-1978 Planning Packet - Laserfiche WebLink

Home Browse Search

Page -6- future who has problems with their waste treatment system. An add itional word of caution on using this type of arrangement, is that little research has been conducted on the functioning of these systems and there is some question as to how well they will operate. A final word of caution should be mentioned for this particular site. The accuracy of detailed soils maps such as that conpleted for Hennepin County is about 50 to 85 percent. Because cf this fact it is essential that an on-site investigation be conducted on each proposed lot to determine 1) if there is a site of sufficient area for a soil absorption system and 2) where this area is. The on-site investigation should consii •, . -i. borings to determine the depth to mottling to indicate seasonal wa...: tables and percolation tests. Since the soil is frozen at this time percolation tests cannot be conduc ted until the soil thaws in the spring. After a site has been located it should be staked off and left undisturbed during any other construction activities. This will help prevent decreases in soil permeability due to con?)action. IVhen the system is constructed the soil moisture content should be such that the soil is friable and does not smear. This will also prevent loss of soil permeability due to smear ing and compaction during construction. V. IVETLAND CLASSIFICATION A portion of the area under consideration for subdivision was identified on the Orono Wetland Inventory conducted by the Hennepin Soil and Water Conservation District. The same general area is also indicated on the Wetland Survey of the Twin Cities 7-County Metropolitan Area conducted by the IMiversity of Minnesota for the Department of Natural Resources. In both cases the wetlands was classified as a Type II wetland with a vegetation type of reed canary grass. The Hennepin Soil and Water Conservation District considers a wetland of this type of secondary importance. In its present form it is not viable or important wetland for water storage purposes. The wetland may have some significance for wildlife. This particular area could be well suited for growing agricultural crops. The most limiting factor for this area is probably not the wetland classification but the fact that the soils in the area classified as wetlands are for the most part unsuitable for an on-site waste treatment system. Since the area does lie in a natural drainageway drainage easements for the area should probably be established. ■I A