honolulu bar floodplain enhancement project
TRANSCRIPT
Honolulu Bar Floodplain Enhancement Project
• Stanislaus River spawning and rearing habitat reduced by mining and dams
• Population constraints identified through two decades of monitoring
Honolulu Bar Floodplain Enhancement Project: Background
• Honolulu Bar Restoration Project designed to increase juvenile salmonid rearing habitat, among other benefits
• Jointly funded by Oakdale Irrigation District and the Anadromous Fish Restoration Program
Honolulu Bar Floodplain Enhancement Project: Location
Project Design: Key elements
Create rearing bench
Augment riffle habitat
Create floodplain
Re-connect side channel
Implementation: Re-connected side channel
• Problems
• Limited shallow water, low velocity rearing habitat
• Stranding
• Project accomplishments
• Nearly one-half mile of re-connected side channel habitat.
• Side channel remains connected
at all flows
Before
After
Implementation: Created small floodplain
• 1.51 acres of excavated floodplain
• Floodplain begins to inundate at ~400 cfs; fully inundated at ~1,000 cfs
Implementation: Created rearing benches
• Approximately one-quarter mile (0.28 acres)
Implementation: Augmented riffle habitat
• 3,325 yds3 of gravel added to the main channel
• Increased spawning habitat
• Increased rearing habitat
Implementation: Project scale
0 10 20 30 40 50 60
Honolulu Bar
Stanislaus River
Cosumnes
Yolo
Thousands of Acres
Stanislaus River
Honolulu Bar
Post-restoration monitoring: Salmonid response
• Bi-weekly redd surveys
• Entire spawning reach
• Pre: 2007-2011
• Post 2012 and 2013
Post-restoration monitoring: Adult salmon
Post-restoration monitoring: Adult salmon
0%
25%
50%
75%
100%
Riffle area 2012 2013
Unrestored
Restored
Proportion of Redds
Post-restoration monitoring: Juvenile O. mykiss rearing
Newly emerged steelheadindicated spawning in the improved side-channel
0
1000
2000
3000
0
0.01
0.02
0.03
1-Jan 31-Jan 2-Mar 1-Apr 1-May 31-May
O. mykiss Flow
0
1,000
2,000
3,000
0
0.1
0.2
0.3
1-Jan 31-Jan 2-Mar 1-Apr 1-May 31-May
Flo
w (
cfs)
Salm
on
/ s
q. f
t.Post-restoration monitoring: Juvenile salmon rearing
2013
2014
0
1,000
2,000
3,000
0
0.1
0.2
0.3
1-Jan 31-Jan 2-Mar 1-Apr 1-May 31-May
Flo
w (
cfs)
Salm
on
/ s
q. f
t.
Honolulu Bar Horseshoe Flow
Post-restoration monitoring: Juvenile salmon production
Post-restoration: Lessons Learned
• Juvenile salmon and steelhead used newly created habitats that were not previously available
• Restored areas were used almost immediately
• Use of restored area by juvenile salmon was not significantly different than unrestored area
• Use of restored areas by adult salmon is higher than unrestored areas
• Ongoing monitoring provides baseline and measures population level response to habitat restoration and other actions intended to increase salmon production
• Response to cumulative efforts to improve salmon abundance not yet clear.
Questions?