6.4. SR 04-20-1998 - Laserfiche WebLink

Home Browse Search

Disposal sites It is proposed that material removed from the lake be disposed of on upland sites in the immediate vicinity. This avoids having to reload the material into on-road trucks. The top soil will be removed from the disposal sites, the material will be spread and compacted by a bulldozer, the topsoil will be replaced and the sites will then be immediately seeded and mulched. So the sediment placed on the disposal sites does not impede future development, except for berms proposed as sound barrier from adjacent US Trunk Highway #10, the typical depth of the material deposited will only be approximately 3 feet. The city will contract the services of a geotechnical engineer during construction to verify and document the conditions of the disposal sites. Sheet 2 of 2 of the attached Lake Orono Improvement Proiect Site Plans shows the locations of the disposal sites, quantities, and details on erosion control measures. Core samples of the sediment in the lake were taken and analyzed. The city worked with MPCA to identify the sampling locations and what parameters were tested for. The sediment was determined to be clean and MPCA has indicated they have no concerns with the quality of this material. Duration of construction The proposal is to draw the lake down in early August of 1998 and begin sediment removal in mid-August. The construction will be completed on or before October 31, 1998. At predicted flow rates, it is estimated that the lake can be brought back to its normal water levels within four days, prior to freeze-up. The above iime frame was selected to minimize impacts on fisheries, wildlife (especially waterfowl) and the summer recreational use of the lake. Further, the time period selected should be one of the driest of the year. Beneficiaries of the project The City of Elk River feels that the project described is imperative. Not only will the immediate lake owners benefit, but Lake Orono is a regional recreation facility enjoyed by thousands of non-lake owners each year. Further, because it draws people to Elk River, the lake is an economic resource for the community and Sherburne County. Alternatives Without a project the lake will continue to decline and pose additional safety hazard to boating. Due to the very low sedimentation yield in the Elk River, additional best management practices within the watershed will facilitate maintenance of the sediment yield, but can not be expected to significantly reduce it. No feasible alternative for keeping a reasonable water depth in the lake besides sediment removal has been