Laserfiche WebLink
y • <br /> Max Green <br /> MGS Consulting Service Corp <br /> 3356 Boone Cir No <br /> New Hope, MN 55427 <br /> August 18,2015 <br /> Melanie Curtis <br /> Pianning and Zoning Coordinator <br /> City of Orono <br /> Crystal Bay,Mn 55323 <br /> Regarding: My response to Bob Bean's 5/1/15 comments about the subterranean interlocking grid system <br /> (Sub Grid)proposed for the Douglas Smith Project <br /> Ms.Curtis, <br /> Per my resent phone conversation with Bob Bean,I am adding the following clarification details to the layout <br /> drawing for this project. <br /> 1) Virgin or natural clay soils must be used for maximum compaction and to provide proper drainage. This clay <br /> soil must contain less than 10 percent fine granular material. Properly compacted soil of this type is to <br /> reduce water retention. We can expect holding forces in the range of 500 pounds per square foot against <br /> the vertical members of the grid if compacted per this requirement. <br /> 2) The use of treated 5 inch by 6 inch timbers are recommended for this project. Alkaline Copper Quaternary <br /> (ACQ)treated timbers are required. <br /> 3) The use of Hex-head steel heavy duty wood screws rated for treated(ACQ)timbers are required. Ten inch <br /> long#12 coarse thread or larger should be used. <br /> 4) Vertical posts must be set in place in 4 foot or deeper virgin or natural clay. <br /> 5) Clear medium aggregate collection zone is required on every layer of the grid. 4 inch drain tiles are required <br /> at the bottom of each layer to illuminate hydraulic water pressure against the walls. Each tile must be <br /> connected to vertical tiles that lead to the shoreline rip rap. <br /> 6) Double rows of silt fence must be used by the installation contractor prior to construction wherever possible. <br /> 7) Because of our concerns regarding erosion and sediment control within the project area my <br /> recommendation is that only experienced contractors with proven successful installations should be <br /> considered for hill side restorations of this type. <br /> Sincerely, <br /> Max Green PE MBA <br />