Catherine Creek provides habitat for ESA-listed Snake River spring Chinook, summer steelhead and Columbia River bull trout.  The Catherine Creek Chinook population is considered one of the highest priority populations for restoration within the Grande Ronde Basin.

Catherine Creek has been diverted at the Davis Dams since 1870 with the earliest water right.  A variety of diversion structures have been in place in the past at both the Upper and Lower Davis Dams including gravel pushup dams. The project proposes to upgrade the two existing concrete diversions structures and install vertical slot fish ladders at each site.  Construction is proposed for the 2011.

Project Objectives:

•Provide continuous and unobstructed adult Chinook passage through both dam sites, during the irrigation water withdrawal period, by designing and constructing fish ladders that meet NMFS Passage Criteria.
•Provide juvenile fish passage through both dam sites, during the irrigation water withdrawal period, when there is flow through the fish ladders (near-zero flow will facilitate juvenile passage in vertical-slot ladders).
•Eliminate false attraction flows for adult Chinook at both dam sites by installing radial gates that direct all available flow through fish ladders and bypass channels.
•Improve all salmonid and native fish passage over concrete aprons outside of the irrigation withdrawal period.
•Facilitate juvenile fish passage back to the stream from the ditch inlets by upgrading  culvert entrances.
•Promote continuous adult and juvenile passage, as much as practical, by designing and constructing facilities that require minimal operational adjustments and monitoring (vertical-slot fish ladders and remote/continuous flow monitoring).
•Reduce scour and excessive erosion that is occurring below each diversion.

Proposed Actions at the Upper and Lower Dam sites Include:

*Work area isolation and fish salvage
*Demolition of portions of the existing structures
*Construction of radial gate support and flow by-pass structures
*Streambed modification and cross vane construction
*Irrigation ditch culvert and headgate improvements
*Installation of the radial gates
*Site restoration/seeding/planting

Construction is proposed for 2011, June 1 - December 31. In-water work will be done July 15 to September 30.