An existing 8.4’x5’ open-bottom arch at RM 11.7 on Deer Creek, a tributary to the Wallowa River, is undersized and a barrier to fish passage.  Additionally, a 3-foot high waterfall over a log weir 15 feet downstream of the culvert outlet ensures only large fish get past this point.  Replacing the arch and removing the log weir will open 2.5 miles of habitat for juvenile steelhead trout and 5.0 miles of habitat for juvenile and sub-adult bull trout.  The proposed solution is to replace this arch with a 23’(span) x 7’(rise) x 40’ bottomless concrete box with wing walls set at stream grade and remove the downstream log weir to restore up- and down-stream connectivity for all aquatic organisms.  Partners include the GRMWP, BPA, & USFS.  USFS engineering designs for this project are complete.

Deer Creek is a 20 mile-long creek located in the Lower Wallowa Watershed of the Wallowa River Subbasin of the Grande Ronde Basin.  From its confluence with the Wallowa River to approximately RM 10, Deer Creek is on private land.  The upper 10 miles are on USFS land, with 6 miles of that in the Eagle Cap Wilderness.  The culvert proposed for replacement is at RM 11.7 on USFS land.  Deer Creek contains spawning and rearing habitat for Snake River steelhead trout and bull trout, both of which are listed as threatened under the Endangered Species Act.  

One of the key limiting factors to bull trout and steelhead distribution in the Lower Wallowa River Watershed are fish passage barriers such as the arch/log weir combination addressed in this proposal.  Replacing this arch will restore passage to 2.5 miles of juvenile steelhead habitat and 5.0 miles of juvenile/sub-adult bull trout habitat.  Replacing this arch will also eliminate the current risk of headcutting under the arch should the log weir downstream fail.

The Deer Creek arch was rated “very high” for replacement in the 2001 Culvert Fish Passage Rating and Prioritization Report by the Wallowa-Whitman National Forest (W-WNF) staff based on Region 6 fish passage evaluation criteria.  The Nez Perce Tribe also ranked the Deer Creek arch and downstream log weir as high replacement priorities in Wallowa County (Barrier Prioritization, Wallowa County, 2007, www.nezperce.org/~dfrm/Watershed/).  USFS aquatics personnel worked with local private, state, and tribal counterparts in identifying the need to replace this culvert, and determined that replacing this arch was the number one priority over all other culverts in the Wallowa County.  The Deer Creek arch is also the W-WNF’s highest priority for replacement in 2008.  Replacement of this culvert is considered a key recovery action for bull trout while also benefiting steelhead.

Proposed practice: remove log weir and replace undersized arch with concrete box.

Detailed description: An existing 8.4’(span) x 5’(rise) x 61’arch will be removed and replaced with a 23’(span) x 7’(rise) x 40’ concrete bottomless box with wingwalls.  The box is designed to pass the 100-year peak flow event.  The log weir downstream will be removed, and 248 total feet of stream channel (extending 116 feet upstream and 68 feet downstream of concrete box and wingwalls) will be reconstructed to its natural gradient of 5% with a bankfull width of 18’ using stream simulation design.  Thirteen rock steps will be constructed approximately 20 feet apart throughout the reconstructed channel to provide grade control and imitate natural steps in the channel upstream of project area.  These actions will restore access to 2.5 miles of upstream habitat for juvenile Snake River steelhead and 5.0 miles of upstream habitat for juvenile/sub-adult bull trout.

The Grande Ronde Subbasin Plan identified the Wallowa Steelhead population as a habitat priority for Grande Ronde steelhead (pg 4).  Key habitat quantity and sediment loads highly impacted steelhead survival in the greatest proportion of steelhead Geographic Areas (pg. 12).  The Grande Ronde Subbasin Plan Supplement (2004) Table 3-2 pg. 16 identifies key habitat quantity and sediment as key limiting factors for steelhead populations in the Lower Wallowa.  Table 3-3 pg. 17 recommends identification and reduction of largest tributary sediment sources resulting in moderate improvements to steelhead abundance, productivity and diversity.  Table 5-4 pg. 40 summarizes priority attributes for the Wallowa-Lostine River and includes key habitat quantity, habitat diversity, and sediment all attributes improved by this project.    

The Lower Wallowa River Watershed is one of the five highest-priority Geographic Areas for the Grande Ronde Subbasin Steelhead Population (pg 16) and is a Geographic Area priority for multiple fish populations (pg 17).  The EDT analysis of restoration scenarios showed that that largest potential increase in both steelhead and spring Chinook production occurs in the Wallowa River watershed.  Based on this finding, priority should be given to improving fish passage in the Wallowa River watershed (pg 37).

Key issues impacting bull trout populations are increasing stream temperatures from water withdrawals and changes in riparian function, fish passage barriers, and competition with non-native species (pg 37).  Bull trout strategy is to address fish passage barriers to ensure connectivity between local populations.  The Subbasin Plan recommends fixing passage barriers due to low flows, diversions and culverts to restore fish passage into habitat (pg 46).  Restoring watershed connectivity by restoring fish passage to good habitats has been identified as one of the methods to prioritize projects in the Grande Ronde Subbasin.