200708500 - UPA Nason Creek Oxbow Reconnection Project
Sponsor: Chelan County Natural Resources Department
Budgets: FY07: $1,212,692 | FY08: $10,000 | FY09: $0
Short description: Project proposes to install two bottomless arch culverts in SR 207 to successfully reconnect 0.64 miles of historic oxbow habitat to the mainchannel Nason Creek. This project will increase Spring Chinook salmonid abundance by 25-50% in the Nason A.U.
Final Council recommendation (Nov 2006)
Funding category: Expense
Recommended budgets: FY07: $630,000 | FY08: $20,000 | FY09: $0
Comment: ISRP fundable qualified: sponsor should consider the ISRP comments. $580,000 of the total project budget ($1.23M) to be funded from another source.
ISRP final recommendation: Fundable (Qualified)
The ISRP is not requesting a response, but the proposal would be improved by addressing the following comments: This project would reconnect a 0.6 mile-long oxbow that was created when state route 507 bisected Nason Creek. The proposal does a good job of describing the history of habitat alteration in Nason Creek, especially along its lower reaches. Using two long arch culverts, one at the inlet and one at the outlet of the oxbow, the site would become a large, slow flowing side-channel of the mainstream that would be connected at nearly all flows. Details of the reconnection project and the hydrological surveys were exceptionally well described. EDT analysis indicated that reconnecting this oxbow would increase Chinook productivity in the entire watershed by 25-50%. The technical background section described two alternatives for restoring this site, neither of which was preferred. Including this information was peripheral to the overall proposal and was not particularly helpful. Additionally, the background section did not provide any estimates of the number of Chinook or steelhead currently spawning in Nason Creek, or an estimate of the additional number of adults that might result from this restoration project, which could have been done using EDT. The proposal includes only plans for implementation modeling, but not effectiveness monitoring. This is unfortunate, because the restoration design is such that estimates of fish coming in and fish going out of either end of the oxbow could be obtained with appropriate traps, and PIT-tagging can be used to estimate downstream survival. This site would provide an excellent place to test the EDT model prediction of a 25-50% increase in Chinook smolt yield. Overall, the ISRP was impressed with this proposal.
Recommended budgets: FY07: (n/a) | FY08: (n/a) | FY09: (n/a)