The Catherine Creek system contains three ESA listed species: Snake River spring chinook and summer steelhead, and bull trout.  All of these populations are severely depressed from historic levels.  Catherine Creek was rated one of the highest habitat restoration priorities in the Grande Ronde Subbasin Plan.  Elimination of passage barriers is one of the highest priority actions.

There have been numerous local Watershed Analyses, Biological Assessments completed by the U.S. Forest Service, Oregon Department of Fish and Wildlife, Grande Ronde Model Watershed Program and local groups within the Grande Ronde Basin.  The most relevant to fish passage issues in Catherine Creek are Stream and Riparian Conditions in the Grande Ronde Basin, Huntington 1993 and The Grande Ronde Model Watershed Action Plan 1994.  Both of these plans identified fish passage at irrigation diversion structures for this reach of Catherine Creek as factors limiting salmon production.  

The regional plan is the Grande Ronde Subbasin Plan (NPCC 2004) and Grande Ronde Supplement (NPCC 2004).   Much of the prior assessment information, as well as personal knowledge of the Basin fish biologists, was incorporated into these plans.  Restoration priorities were established through the planning process by the Grande Ronde Subbasin Planning Team. These documents identify Catherine Creek as the number two priority geographic area for Snake River ESA listed spring chinook.  Catherine Creek and the Upper Grande Ronde chinook populations were predicted (EDT analysis) to experience “dramatic” population increases as a result of habitat restoration work.  Although the plan did not identify individual passage barriers (lack of data); fish passage, in high priority watersheds, has always been considered one of the key issues where blockages are identified.  

The Grande Ronde Supplement identified key habitat quantity and temperature as factors limiting chinook survival in this reach of Catherine Creek, Table 3-1, p 15 (see Pisces attachment). The inability  of bull trout, and juvenile steelhead and chinook to pass the Townley Dobbin Diversion at low flows when water temperatures are warming limits access to better habitat and cooler  water  upstream of the site.

The Godley Ditch irrigation diversion structure is one of nine permanent diversions on Catherine Creek.  The Godley diversion is located in the City of Union. It has been identified as a barrier to juvenile Chinook and steelhead, bull trout and other native species. All nine diversions, with the reconstruction of the Davis Dams (also proposed in 2011) and the installation of this fish ladder, will now provide satisfactory fish passage for ESA listed Snake River spring Chinook and Snake River summer steelhead.  

The Godley Ditch diversion structure, depending of flows, can be a barrier to juvenile salmonids as well as other native fish such as bull trout when water is checked up for irrigation withdrawal.  Check boards are normally not installed until late-July as stream flows decline.  By this time the adult Chinook migration has passed the structure.  However the boards, which are in place from late-July through the end of October restrict passage for juvenile Chinook and steelhead, as well as bull trout and other native resident fish throughout the summer when water temperatures are warming and fish need to move upstream to find more suitable water temperatures.

The existing facility consists of a concrete wall, wing- wall, headgate and concrete sill extending across the channel.  Brackets which hold the check boards are located on the downstream side of the concrete sill. According to the irrigator the existing facilities were constructed by the Corps of Engineers in 1950 just after a major flood.  About 1990 the irrigators added to the cross-channel concrete sill by pouring another level above the original sill constructed in 1950.  

The project objective is to provide year-round fish passage at the site for all life stages of salmonids and other native species.

The Grande Ronde Model Watershed (GRMW) with the cooperation of the irrigators, propose to correct the passage problem by installing a step-pool fish ladder and making some in-channel modifications.  

The proposed project will include the following major components:

Work area isolation and fish salvage
Construction of the step-pool fishway
Streambed modification and cross vane construction
Site Restoration