Correspondence re erosion control

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- o�`'��o � , a ��>J�� • I •�� Bonestroo '�� x�i �6;�v�. O�'%. , � ,��.a �v,�, �9kESI1�4:s� November 13, 2009 Rollingbrook Homes 7378 Whitehall Road Shakopee MN 55379 RE: Permit 2009-00513 - 200 Biederwood Drive The active summer construction season is fast drawing to a close here in the state of winter and frozen ground. As we move into a new season it is important we take the proper precautions on our active sites to help eliminate any erosion problems or added expenses that may be incurred due to winter freeze thaw events and the inevitable spring runoff. As construction continues throughout the winter in the City of Orono it is important to minimize the amount of open soil by providing temporary or permanent cover, one of the key elements in preventing soil loss. It is also required that the appropriate BMPs be maintained on-site by December 1, 2009 as follows: ■ Exposed soil areas must be stabilized with the appropriate seed mix and erosion control blanket, disc anchored mulch applied at a rate of 2 tons per acre or other effective means to control erosion. o Areas requiring stabilization will include but are not limited to small miscellaneous areas, landscaping areas, sidewalk backfill,non-active stockpiles, finished grading areas, etc. o Areas being worked after November 26th must be stabilized weekly until construction ends. o In the event that it snows and there are frozen ground conditions, mulch can be applied effectively over the snow. ■ Seeding must be completed with the appropriate seed mix as indicated below. Dormant seeding shall be done in the later fall after the soil temperature is consistently below 50 degrees Fahrenheit. Seeding done before or after the indicated seed dates may require reseeding if the seed does not take. In the event that it snows and there are frozen ground conditions, seed can be applied effectively over the snow. Fall and Dormant Seedin Dates Seed Mixture Number Fall Dormant Seeding 100 Aug. 1 —Oct. 1 Oct. 20—Dec. 1 150, 190 July 20—Oct. Oct. 20 -Dec. 1 20 240,250,260,270 July 20— Sept. Oct. 20—Dec. 1 20 310, 325,328, 330, Sept. 20—Oct. Oct. 20—Dec. 1 340,350 20 ■ Rock construction entrances to access the construction site and prevent tracking sediment off site ■ Silt fence or an approved perimeter control device shall be installed to control runoff ■ Soil stockpiles should be eliminated or consolidated to the extent as possible and be protected with perimeter control and mulch applied on all stockpiles that will remain dormant for the winter months. ■ Storm Sewer inlet protection including curb and gutter catch basins,parking lot/road drains, and backyard drop inlets must be: