6.4. SR 04-20-1998 - Laserfiche WebLink

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4. Work with the watershed board and the comprehensive water plan committee to develop a water quality action plan to address: best management practices within the Elk River watershed - The sedimentation rate of the Elk River is very low when compared to other rivers monitored by the USGS in Minnesota. Much of the river is lined with natural buffers. However, the sedimentation rate could be reduced the natural buffers should be maintained. water quality goals for the Elk River watershed - A member of the Lake Orono Improvement Association has recently been appointed to the Sherbume County Water Plan Committee and will be acting as a liaison for the city. Sediment removal The removal of sediment from the lake described in study recommendation #2 is the issue that mandates the EAW process. The lake study found that them was no net deposition of suspended sediment in Lake Orono and the sedimentation that does exist consists of primarily the coarser bedload fraction of the Elk River's sediment load. The city is proposing to remove 1 to 2 feet of sediment from the western most lobe of the lake (Area I, approximately 90,000 cu. yd.) to restore its original navigable depth. This lobe will again act as the sedimentation basin for bedload from the river in the future. In addition, the city plans to remove sediment that poses a safety hazard to boating from two other areas of the lake (Areas II, 3,500 cu. yd. & Area IV, 13,500 cu. yd.). Approximately 2,000 cu. yd. is proposed to be removed from Area III to improve access and clean out an existing area where sediment currently deposits. An optional area the city is considering involves the removal one foot of sediment from the top of four high spots that pose hazards to boating. The material removed from the high spots mentioned is proposed to be left on adjacent areas of the lake bed, away from the channel of the river through the lake. The location of this material precludes its removal without bridging the river channel through the lake or repeatedly cross it. It is our opinion that both of these options would have a negative effect on water quality. This work involves the moving of approximately 6,000 C.Y. of material. A total of approximately 115,000 C.Y. of material are proposed to be removed and/or graded by the project. The total project area encompass 61.9 acres. For details on the locations, quantities, and depths see the attached sheet 1 of 2 of the attached Lake Orono Improvement Proiect Site Plan.