On January 8, 2019 Council approved an Interlocal Agreement (R-2019-00) with Yakima County which transferred $4,734,723 Department of Ecology Floodplains by Design grant funds from Yakima County to the City to complete the cooperative design, permitting and construction of the Nelson Dam replacement, fish screen and associated piping including the Rambler's Park By-pass project.
This contract for consulting services is the first step as outlined by the Interlocal Agreement for the design, permitting, bidding and construction management. Nelson Dam is located just upstream of the twin bridges on SR 12 where the City diverts water for irrigation. It was damaged during the 1996 and 2011 floods and is nearing the end of its life expectancy. The project will replace the existing Nelson Dam and the connected fish by-pass roughened channel structure. This work will reduce flood risk and flood risk maintenance. Improve fish habitat conditions, particularly for Endangered Species Act listed Steelhead and Bull Trout, by improving the natural physical processes of the river. The project consists of:
· Demolition of existing site floodplain and channel structures
· Demolition of the existing Nelson Dam
· Construction of a new two acre Nelson Dam roughened channel by-pass and n
upstream weir
· New fish screen
· Piping
· Excavation of 2,500 feet of floodplain dam approach channels
· Placement of a road protection structure
HDR Engineering has been award the contract to provide the engineering design, bidding, and construction services for the Nelson Dam Replacement, fish screen and associated piping project.
The design and permitting process will take approximately 18 months. Construction is expected to begin after the 2020 irrigation season. The design, permitting and construction is estimated to be near $13,500,000. Funds are:
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$4,700,000 from Yakima County’s Floodplains by Design grant
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$6,000,000 Irrigation bond (supported by current irrigation rates)
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Anticipated funding from Bonneville Power Administration, amount TBD
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Anticipated funding from Bureau of Reclamation, amount TBD
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Anticipated funding from Yakima Basin Integrated Plan TBD
The terms of the Agreement for the design and permitting shall be in an amount not to exceed $1,819,600.00. |