IMPORTED FROM CBFWA MODIFICATIONS DATABASE ON 01-07-2010

"Proposed action achieve the objective(s)"

Phase II Improvements will include:

?creating resting areas by constructing small rock weirs, placing woody debris and boulders, creating meander, constructing pools and runs, revegetating for shade, and recruitment of woody debris

?increasing flood plain width by deepening some areas and creating a more typical creek shape

?removing culvert barriers from ponds 2 and 3

?restoring free access for wild fish to and through ponds 1, 2, 3, and 4

?restoring year-round surface water flow throughout the isolated side channel and pond complex.

Phase II is scheduled for construction this summer and will include open channels with control structures between Pond 1 and Pond 2 and between Pond 2 and Pond 3. Other improvements include a metal control structure between Pond 5 and Twisp River on the existing channel to allow control over fish passage into the site.

The channels between the ponds and the channel back to the river will be sized for a flow of 2 to 6 CFS. Average width of the new channel will be less than 5 feet. The average change in elevation between the ponds is about 3 feet which requires 4 ? 5 drop structures in each channel with a 0.8 foot drop at each structure or less. The rock drops will be typical Rosgen type vortex weirs using rocks at least 2 foot in diameter. A total of 14 rocks will be required for each structure which includes a base rock buried beneath the upper rock for stability. The first channel between Ponds 1 and 2 is about 115 feet in length and will require one 30-inch diameter HDPE culvert underneath the access road to the site. The second channel between Pond 2 and Pond 3 is about 90 feet in length which requires that the rock structures be about 30 feet apart. A very small piece of geotextile liner is used on each of the rock structures to assure that low flows still provide adequate fish passage. No headgates or other structures will be used to control or stop flow between ponds. The channels will accept any overflow from the pond.

The metal control structure between pond 5 and the Twisp River will be constructed of ?? steel plate and will have a low flow notch that can be closed off with stoplogs to raise the water surface and create a passage barrier at certain times of the year when it is not desirable to have fish passage into the pond system. For the most part, this structure will be used to prevent native fish and especially Bulltrout from interacting with hatchery fish being reared in the pond. The height of the structure above the streambed will be about 4 feet. Large rocks will be used around the edges of the structure to prevent erosion of the banks around the structure.

The banks of the constructed channels will be lined with sod cut from the area to stabilize the channels. Additional revegetation will be completed in the disturbed area using native plants and shrubs. The channel base will be lined with sized gravels suitable for spawning. Gravels will be of sufficient depth to deter encroachment of canary reed grass, which is prevalent in the lower Twisp River, from establishment.

"Is the situation the result of a catastrophic event that occurred within the existing location?"

No

"Has a habitat/population/mechanical/structural dilemma developed in the proposed study location since the contract was signed with BPA?"

Yes

"Budget Impact"

$39,851.00