[env-trinity] With High Trinity River Flows Comes Gravel (Coarse Sediment)
bgutermuth at mp.usbr.gov
Wed Apr 29 12:28:50 PDT 2009
I understand that some folks on the Trinity List serve did not receive this -
My apologies for dual postings
Hi All -
The Trinity River Restoration Program is getting ready to implement our high flow coarse sediment (gravel) injections to the Trinity River next week, starting on April 29th. Gravel of 3/8 to 4 inches in diameter will be added to the river from two high velocity locations just downriver of the Lewiston dam: 1) Sawmill site (on California Department of Fish and Game managed lands) and 2) the Diversion pool (by the weir on U.S. Forest Service managed lands). From these locations, the gravel will be swept downriver and distributed by high flows. The gravel will meet spawning and habitat needs in the reach as it is moved by the river to create river features (e.g., point and mid-channel river bars) and complex habitat in downstream areas.
A local Trinity County contractor is already delivering the gravel for storage at the sites. Approximately 1,000 tons will be pushed into the river at the Diversion pool and 2,500 tons will be placed by conveyor belt at the Sawmill site. Actual dates, timing, and quantities of injected gravel will vary as the different contractors at the two sites get their systems for delivery in place and flows increase. The entire quantity of gravel, 3,500 tons, will be placed between April 30th and May 4th when flows are between 3,500 and 4,500 cubic feet per second. No gravel will be placed on Sunday, May 3rd.
This years coarse sediment addition will meet long-term habitat requirements for anadromous fishes and meets the conditions for long-term gravel additions that were included in permits acquired for implementation of the 2008 Lewiston-Dark Gulch channel rehabilitation project.
If you have any questions, please give me a call.
Trinity River Restoration Program
PO Box 1300 (mailing)
1313 S. Main Street (physical)
Weaverville, CA 96093
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