The Channel Sediment Removal Project

Twin lakes ID Channel

While boating through the Channel between our two lakes last summer you may have noticed a plume of muddy sediment kicked up by your propeller. That plume is a clue to a problem beneath your boat we need to address. Since dredging was done in the mid-1950s, sediment and aquatic vegetation has filled the channel to the point boats can barely navigate and on occasion pass so close to each other that safety has become an issue. The shallow navigation channel is a major concern because it greatly limits boat access between the lakes late in the summer, and it can cause expensive damage to boat propulsion equipment. Also, propellers of each passing boat stir up nutrients that degrade water quality by promoting growth of aquatic vegetation.

Your TLIA Board has a plan to address this pressing issue. We have applied for permits to suction dredge about two feet of sediment across a 50-foot-wide navigation channel between the narrows at Upper Twin Lake east to the bridge at the entrance to Lower Twin Lake and north from the bridge to the channel boat launch. Approval of all permits for the project is expected this spring. The project is expected to remove approximately 8,600 cubic yards of sediment which will be pumped via floating pipeline to the channel boat launch area, where polymers will be added to the slurry and then pumped into large geo-textile bags for dewatering. After dewatering for about five months, the residual sediment will be loaded and hauled about 3 miles to the Scarcello ranch to be used as a soil amendment.

The Board has retained the services Envirodredge, an experienced company, to help us implement the project. Estimated project costs are approximately $210,000-$250,000. The project may take 4-6 weeks to complete beginning October 1, 2022. If you would like to contribute to this project, you can donate under “How to help” tab on the website. We will update you on this project as more information becomes available.

If you have questions about the project, please contact Mike Knowles at (509) 863-4359, Doug Jayne (509) 710-7188, or Debbie Andrews at (724) 553-8779.

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