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200705400 - Entiat River - UPA - Stillwater Restoration Project

Sponsor: Chelan County Conservation District (SWCD)

Budgets: FY07: $267,544 | FY08: $32,320 | FY09: $9,459

Short description: Enhance instream habitat complexity and reduce sediment delivery to salmonid spawning habitat from rapidly eroding streambank using LWD placement in 0.5 miles of the Stillwater Reach of the Middle Entiat AU. Riparian revegetation will occur along 0.1 mile.

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Final Council recommendation (Nov 2006)

Funding category: Expense

Recommended budgets: FY07: $0 | FY08: $0 | FY09: $0


ISRP final recommendation: Not fundable


The ISRP believes this proposal, while well intended, still has some serious deficiencies. The responses to the ISRP comments do not provide sufficient context to determine whether or not the project would address a significant problem in the Entiat watershed. The information on fine sediment in the gravels provides an indication that sediment levels are high at the site, but whether or not that sediment is being produced from the eroding banks at the project area is not clear. The McNeil core sample data are limited to the Stillwater reach, and there was little information on conditions elsewhere in the Entiat subbasin. Because sediment data are available for RM 0.5-34 since the early 1990s (a period that included several high intensity wildfires in the drainage), it would have been very helpful to have included a discussion of the role of fire in delivering sediment to the mainstem Entiat and what we know about how that sediment has been routed in the ensuing years. Without this spatial and temporal context it is difficult to ascribe the relatively high fines in the Stillwater reach to either bank erosion or fluvial delivery of other sediment from sources in the upper basin. The photographs certainly suggest bank erosion is a problem, but there was no way of determining its significance relative to other factors. Project sponsors suggest that the work is needed to reduce bank erosion from feet per year to inches per year. Supporting evidence is needed for this statement as well as for the comment that gravel recruitment from upstream sources is adequate. The statement that spawning gravel is recruited primarily from upstream and deposited at the study site also was not well substantiated. What is the composition of the eroding banks at the project site? Do they contain gravel? If they do and they are eroding rapidly, these banks may be an important source of gravel. Implementing the project without a better understanding of gravel recruitment would be risky. The response states that closely spaced (10 ft.) log structures along the streambank are needed to prevent scour pockets from forming. While scour pockets may be deemed undesirable from a sediment standpoint, it would have been useful to have included a discussion of its implications for fish habitat. If preventing bank erosion is the primary objective, why not just use rip-rap? The ISRP realizes rip-rap is almost always an undesirable solution and shouldn't be used in this instance, but the response could have been clearer if the LWD additions had been described in terms of their overall benefits to fish habitat (vis-à-vis sediment and rearing space). In that way, it would have been possible to explain why so many LWD pieces were being proposed, or if project sponsors were willing to reduce the quantities a bit to more closely emulate natural LWD loading. Additionally, given the width of the floodplain at this site (600 ft.), it is not unnatural for logjams to break up and re-form during high flow events. These natural disturbances are usually quite good for maintaining ecologically functional floodplains. It is understandable that the project would want to protect riparian tree plantings from floods for the first few years, but artificially anchoring LWD may have undesirable, and expensive, long-term consequences. Some provision for LWD movement may be worthwhile. The ISRP's comment about changes in nutrient input was not addressed. Nutrient input does not necessarily require overland flow. Dissolved nutrient input occurs through subsurface flow, and riparian root systems are likely to intercept some of the nutrients moving through the soil to the stream, at least during the growing season. The benefits associated with re-establishing vegetation along the channel are likely to outweigh any negative effects associated with nutrient interception. But the claim that the vegetation will increase nutrient delivery to the channel may not be true. The M&E section of the proposal remains weak. It is not clear that the ISEMP monitoring effort will measure parameters that are relevant to assessing the project's effectiveness. One of the primary objectives is the reduction of fine sediment in spawning gravel, but summer snorkel surveys provide only very indirect evidence that spawning conditions have changed. The gravel samples will provide some indication, although the connection between fine sediment concentrations in the gravel and sediment coming from the banks at the project site would need to be made to be certain that any reduction was related to the bank armoring. The most relevant biological measure would be an assessment of egg to fry survival, but there was no indication that this will be measured. If the monitoring effort is limited to implementation monitoring, as the response states, then the focus should be streambank and riparian vegetation. Instream performance measures will require a much more significant effort to detect real change. Hopefully, the ISEMP program will pick the instream metrics up, but this proposal should have concentrated on the streambanks and riparian zones and, especially, the success of revegetation efforts and the performance of the log structures. In summary, while the ISRP believes this site deserves protection, the proposal should have provided an improved context for the restoration proposal, more attention to simulating natural wood loading in the Entiat River floodplain, and a more focused M&E plan.

Response loop edit

See the sponsor's revised proposal from the response loop. You'll be taken to CBFWA's proposal system in Section 10 where most sponsors uploaded revised narratives or other responses to the ISRP comments.

State/province recommendation: Washington

Review group: Washington list

Recommended budgets: FY07: (n/a) | FY08: (n/a) | FY09: (n/a)

Comment: See Washington guidance