11-21-1977 Planning Packet - Laserfiche WebLink

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977 - PAGE 2 >ER LAND COMPANY ID) 10 ORCHARD ROAD :SION (PRELIMINARY) BY ENGINEER ;0N OF BONESTROO or n- wn e er- e soil commended water the sur- soil 1 soils I j X ■V -MINUTES OF A PLANNING COMMISSION MEETING HELD NOVEMBER 21, 1977 - PAGE 3 COLPEPPER LAND COMPANY (Continued) (#306) Dundas (Du) and Minnetonka (Mt) - The maximum height of the seasonal water table in this soil as indicated by the presence of mottles is usually between 1 and 3 feet. If mottling occurs at less than a 2 foot depth, installation of any soil absorption system is not recommended. These soils are shown as a blue cross-hatch on the enclosed soil map. Erin (En) - Has a high clay content in the subsoil, vjhich often results in percolation rates in excess of 60 minutes per inch. For this reason, it is recommended that an innovative mound system be installed on these soils. Mound systems cannot be installed on slopes greater than 6 percent. The Erin soils with slopes from 67o to 12% are shown on the enclosed soil map as a red cross-hatch. The Erin soils v;ith slopes from 127. to 187o and from 187o to 357o are shown as solid red. Based on the Hennepin County preliminary soils report, there are major areas of the proposed plat where no type of soil absorption system is recommended and major areas of the plat where there would be serious difficulty with soil absorption systems due to water table, soil type and slope. A plan has been prepared for the proposed plat outlining the major steep slopes. Normal residential development can generally be accomplished on slopes up to approximately 12% without extra ordinary problems. From 127o slope up to about 187o slopes, very special design consi.derations must be incorporated into the development to prevent serious erosion problems. No development is recommended on slopes greater than 187o. When both the adverse soils and the steep slopes are overlaid on the proposed plat, there appear to be very fev; areas left for suitable residential building and septic tank/drainfield placement. It is recommended that the proposed plat not be approved until the City of Orono can be assured that an adequate and acceptable individual sewer system can be provided for each lot to be platted. It must be understood that the Hennepin County soils report is a preliminary evaluation, but the report suggests that the magnitude of soil problems rela tive to ground absorption systems is serious enough to required additional in formation prior to any further consideration. Tlie external boundary restraints on the proposed plat will allow access only from Orono via Orchard Road. The two narrov; bridges on Orono Orchard Road at either end of the plat and the restricted sight distance suggest only one entrance as indicated on the plat. The street alignment does traverse some very steep, wooded slopes throughout the plat and does intrude several exist ing marsh areas. The steepest slopes go through the middle of a number of proposed lots rather than along the edge, making placement of buildings more difficult. The terrain is very difficult to deal with from a development standpoint. However, it is suggested that alternate layouts be developed that may be more sensitive to the prominent topographical features of the land. i I MINUTES OF Mr. Ron Bas Company, wa response to steep slope, that the de’ designed th< they felt c< requirement would creati to the natu] lot contains of holding c Concerning 1 had contact€ perc tests, revealed th€ which they indicated tl would suppoi recommended proceed. When asked i and guarante replied that systems; how certify that years. It i Water Conser problem of t Some feeling were that th more informa septic syste each of the a variance t must show th public. After much d that the pre as applicant and informat septic syste] Nays (0). Bruce Kelle; reviewed th tor pointed tion easeme] is not incli engineer ha; ing said ea; by the City i ^