reconnecting fluvial westslope in skalkaho creek is this working and how do we tell?
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Reconnecting Fluvial Westslope in Skalkaho Creek
Is this working and how do we tell?
Skalkaho Creek
Major Ditches and Dams
Major Ditches and Dams
Skalkaho Creek
Republican Ditch
Hedge Ditch
2001
• Fluvial cutthroat pass over all dams and reach Bitterroot National Forest
• Ditches entrain large numbers of cutthroat, bull and brown trout
2002 - Skalkaho Creek Fish Passage and Protection Project
• Identifies locations of fish entrainment• Recommends various strategies
Decision
• Attempt to aid juvenile fish and adult spawners downstream to Bitterroot River
• Do nothing at this time to help fluvial fish move upstream
$900,000
2004
2008
Pros and Cons for Success
Pros• Migratory Cutthroat still
connected somewhat• Many downstream
migrating juveniles in upper creek
• Adult post spawners lost into ditches
• Small number of cutthroat and bull trout in lower creek.
Cons• Fish in ditches (bull trout)
may be residents (L. Nelson)• Worried about all the
brown trout in lower creek• Dewatered reach may be
problematic• River Temperatures and
species may be problematic
Studies pertaining to Skalkaho projects
• 2005 – Steve Gale (Prior to Siphons)– Skalkaho system selecting for residents– Screens returning thousands of CT to Skalkaho– Post spawning adult cutthroat being entrained– Screening may help maintain fluvial fish– Worried about brown trout
• 2007 – Ryan Harnisch– Screens are working well – Siphons should stop entrainment of post spawn adults– Monitor it!– Worried about brown trout
0
50
100
150
200
250
mm
ho
sLower Skalkaho Creek Conductivity
2004
2008
5.8
13.1
20.6
16.8
1.2
3.6
8.1
0.3
Monitoring Reach
Restoration Monitoring
• 2 Single Pass sites in Dewatered Reach
• Population Estimates in Creek
• Downstream migration -- Screwtrap
• Bitterroot River
5.8
1.2
3.60.3
Monitoring Reach
Skalkaho Creek 5.8
Brown trout > 6”
Se-ries3
0
20
40
60
80
100
120
140
160
1996 2010
Westslope Cutthroat > 6”
Se-ries3
0
20
40
60
80
100
120
20101996
5.8
1.2
3.6
8.1
0.3
Monitoring Reach
Dewatered Reach Single Pass
1991 2001 2009 2010 2011 20120
10
20
30
40
50
60
70
80
90
100
Skalkaho Creek 3.6Single Pass
Brown TroutCutthroat Trout
2001 2009 2010 2011 20120
5
10
15
20
25
30
35
40
45
50
Brown TroutCut-throat Trout
Skalkaho Creek 1.2 Single Pass
Skalkaho Creek Screwtrap Duration201020052006201020052006High flowLow flowHigh flow2011
April------------------------------------October
Westslope Cutthroat > 10”Hamilton Section
0
50
100
150
200
250
300
2001 2007 2010
4 and 5 recapture estimates
Restoration Scorecard
• Single Pass in Dewatered Reach
• Population Estimates in Creek
• Downstream migration
• Bitterroot River
Conclusions (stay tuned)
• Screens and Siphons are working as planned• Monitoring data for fish is mixed and, in
general, disappointing• Documenting change in a relatively small
population of migratory cutthroat in a large drainage is not easy using routine methods
• Still worried about brown trout• Is the fish community and habitat in the river
also a controlling factor?