1.
Conceptual Model for Assessing Recreational Safety
Related to Habitat Improvement Projects
R. Leif Embertson, MS, PE
Salmon Recovery Funding Board – Salmon Habitat Conference
April 27, 2011
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2.
Approach
Recreational user safety is a function of;
— Reach characteristics
— Structure characteristics
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3.
Reach Factors
Define the
recreational use
— Frequency of use
— Access to project
reach
— Recreational
flow range
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4.
Reach Factors
Define the recreational use (continued)
— Ability of users
1 2 3
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5.
Reach Factors
Define the geomorphic indices
— Channel type
1 2 3
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6.
Reach Factors
Define the geomorphic indices (continued)
— Channel gradient
— Channel stability
1 2
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7.
Reach Factors
Define the geomorphic indices (continued)
— Frequency of natural large wood*
wood
• Low (<25th percentile(%))
• Moderate (>25th and <75th %)
• High (>75th %)
*.Fox, M., S. Bolton, 2007. A Regional and Geomorphic
Reference for Quantities and Volumes of Instream
Wood in Unmanaged Forested Basins of Washington
State. North American Journal of Fisheries
Management 24:342-359, March 1, 2007.
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8.
Structure Factors
What is location of the structure?
— Outside of a channel bend?
— Within wetted area during recreational flow?
SOUTH FORK NOOKSACK SOUTH FORK NOOKSACK
SKOOKUM REACH FOBES REACH
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9.
Structure Factors
What are the
structure
characteristics?
— St i
Strainer
potential
— Structure type*
*.Abbe, T.B. and D.R.Montgomery. 2003.
Patterns and Processes of Wood
Accumulation in the Queets River Basin,
Washington. Geomorphology 51:81-107.
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10.
Structure Factors
What is the avoidance
potential?
— Sight Distance
— Can the structure be
portaged?
— Wading safety factor
(WSF)*
WSF = Velocity*Depth
*.Abt, S.R., Wittler, R.J., Taylor, A., and D.J. Love,
1989.
1989 Human stability in a high flood hazard zone zone.
American Water Resources Association, Water
Resources Bulletin, 25(4) 881-889, August 1989.
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11.
Assessment Model
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12.
Project Example
Cavanaugh Island
Restoration South Fork
Nooksack River
Objectives
1. Increase duration and
amount of flow within
side channel
2. Increase pool habitat
3. Promote forested island
stability
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13.
Project Example (continued)
j p ( )
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14.
Project Example (continued)
ELJ 4 – APEX
JAM
RESULT
MODERATE SAFETY
RATING
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15.
So Now What…
Risk can be mitigated through
— Public education/outreach
— Public notification
— Signage
— Monitoring
— Adapti e management
Adaptive
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16.
Questions / Discussion
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