The Methow Valley Irrigation District (MVID) East diversion is located on the Methow River at river mile (RM) 44.8. The historic diversion dam was identified as a partial passage barrier to listed salmonids and bull trout in the Methow Basin. Two-thirds of the width of the historic diversion was removed under separate funding in 2007 and 2008.  Irrigation canal operations require annual excavation and placement of material within the active river channel to maintain adequate diversion volume, to control spill at the wasteway and to maintain head necessary at the intake to meet irrigation needs. This annual activity adversely affects fish usage within the immediate area of disturbance.

Improvements completed in 2008 - 2009 under first year contract:

1. Complete value engineering (VE) study / review of alterations proposed by BOR
2. Participation in and review of HDR redesign process based on VE
3. Participation in agency coordination / consultation meetings in support of new design
4. Develop agency funding agreements

Improvements Proposed under second year contract, described in greater detail in the SOW, are as follows:

1. Intake facility - construction of new concrete intake structure at station 12+50, together with appurtenant fences, utilities, trash rack, walkway, and access improvements.

2. Conveyance facility - placement and burial of 2440 lineal feet of PVC c905 pipe material between the new intake facility and the proposed new headworks structure downstream. Work to include necessary excavation within the existing intake canal to establish grade; placement of bedding, pipe, pipe cover, and hardened surface; construction of flood height berm, soil and slope stabilization; and revegetation of affected side slopes as required. Twin 36-inch pipes will deliver water into a concrete sediment control vault.

3. Sediment wasteway and headworks  - Existing headworks consisting of concrete and metalwork will be removed and disposed of. At the downstream side of the sediment vault will be new headworks consisting of concrete bulkhead and two wing walls, new 60-inch slide gates, and stop log slots. On the river side of the sediment vault will be two 24-inch steel sluice pipes, to carry accumulated sediment back to the river during periodic flushing.  Sluice pipes will be controlled by 24-inch slide gates.  Wasteway and headworks will include associated walkway, handrail, and access fencing,

4. Fish bypass improvements - roughened chute will be constructed at the outfall of the fish bypass system, consisting of a series of small step pools that transition from the bypass outfall to the river.  Each pool will utilize large river rock to serve as pool weir.  This roughened chute will allow for downstream passage of fish to re-enter the river safely rather than dropping into an unknown river surface water depth.

5. Fish screen refurbishment - existing belt style fish screens were installed during the renovation of the screen facility about 6 years ago. Screen facility project was funded by BPA. Fish screens were placed by WDFW. Excessive siltation from the existing intake canal has resulted in accelerated wear to the plastic screen belts and bearings. WDFW has completed an assessment of the existing screens and is recommending structural modifications to elevate the screens about 1 foot, and refurbish / replace the worn belts and bearings. Existing screen belts are in the final year of warranty, which will offset costs approximately $5,000 on materials only, if completed in 2009.

6. Conveyance improvements - immediately below the new headworks, it is proposed to enclose the first 400 lineal feet of the canal, with 48-inch buried ABS or HDPE pipe.

7. Site work - general site work associated with the project includes dewatering and isolation of the work area through use of cofferdams and pumping, access road improvements, erosion control, revegetation, and restoration of staging areas.

Three funding sources have been secured for construction of the preferred alternatives identified through the VE process.  BPA will be responsible for a share (not to exceed $624,988) of the total project costs. Washington Recreation and Conservation Office awarded funding in the amount of $300,000. USBOR has obligated funds to MSRF obtained through the American Rescue and Recovery Act program, in the amount of $320,000.

Objectives:

1. Reduce annual disturbance to river from irrigation structure maintenance
2. Reduce mortality associated with operation of fish return and screens
3. Reduce mortality associated with maintenance of intake canal and wasteway
4. Increase reliability of adequate flows required for fish passage
5. Reduce sedimentation associated with intake canal side slope failure
6. Reduce annual instream maintenance work needs

Background Information

Implementation of the MVID East project was delayed at the request of funding agencies to ensure that the preferred alternative satisfied resource agency concerns and provided assurance of efficient use of awarded grant and contract funds.