Thursday, April 22, 2010

Sediments to be Captured in North Park Lake

The U.S. Army Corps of Engineers is taking steps to make sure sediments do not flow out of the nearly dry North Park Lake while contractors dredge the body back to its original depth. The lake was drained last year to allow for dredging this summer. Two creeks flow into the lake and they have cut new paths through the several foot thick layer of sediment taking material down stream with them. The corps will divert those streams over the next few weeks and add extra rock filters to capture the sediments that are now making Pine Creek below the dam muddy. A wetlands barrier will also be installed on Pine Creek upstream of North Park Lake to catch sediment before it enters the lake.
Contractors placed an initial erosion control structure downstream of the North Park Lake Dam outlet in late March, but sediment continues to escape. The Pennsylvania Fish & Boat Commission is evaluating water quality and plans to continue its trout stocking in Pine Creek at a later date. However, stocking activities will be postponed or canceled if conditions are unfavorable for trout. The County and Corps will also evaluate the effectiveness of the erosion control measures and make adjustments as necessary during the project. The $13 million restoration of the 65-acre lake is expected to be complete by May of next year. North Park Lake is the largest man-made lake in Allegheny County. It was first constructed in 1935. Since then it has lost half of its original depth.

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