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TRANSCRIPT
Fish Passage Barrier Removal in Washington State
Thanks to:Julie Heilman, WSDOT
Heather Pittman, WSDOTKeelan Jensen, WESTShelby Fowler, WEST
Dan EggersWEST Consultants, Inc.
Statewide Fish Passage Barriers
Fish Passage Barrier
WSDOT-Redrawn from Fish Passage Short Course, John Runyon
Definition: Anything that hinders any life stage of fish from moving through a water way.
Types:o Velocity
o Depth
o Water surface drop
o Slope
o Structures such as tide or flood gates
Fish Passage Design Criteria and Guidelines
https://wdfw.wa.gov/publications/01501/wdfw01501.pdf
Regulations
o Washington Administrative Code (WAC) 220-660-190
Design Guidelineso 2013 WDFW Water Crossing Design Guidelines
(WCDG)
o WSDOT Hydraulics Manual – Chapter 10 (LWM)
o 2008 USFS Stream Simulation Manual
o HEC-18 (Scour)
o Others
Fish Passage Design Approaches
Geomorphic Approach
o Minimize the effect on the natural processes
Stream Simulation
o Typically smaller crossings with bankfull width less than 15 feet
o Reference Reach
Bridge Design
o Crossings with bankfull width over 15 feet
o Confined or unconfined
Hydraulic Design
o Typically for structures such as ladders, weirs, roughened channel.
Source: WDFW WCDG 2013
Geomorphic Data Collection
Bankfull Width (BFW)
o Most important parameter in culvert design
o Reach consensus in field with stakeholders present
Longitudinal Profile
o Used to establish crossing elevation and channel slope
o Typically detailed survey +/- 300 feet from crossing. LiDAR used to supplement.
Channel Substrate (Pebble Counts)
Channel Shape and Pattern
Large Woody Material (LWM)
Constraints
Stream Simulation Approach
Suitable for sites with:
o BFW less than 15 feet
o Moderately confined
Structure Size
o Minimum opening = 1.2*BFW + 2 ft
Structure Slope
o Not to exceed 25% of existing reach slope
Countersink
o 30-50% of culvert rise
Freeboard
o 1 to 2 feet during 100-year peak flow
Source: WDFW WCDG 2013
Source: WDFW WCDG 2013
Bridge Design Approach
Two Methods
o Confined or Unconfined determined by floodplain utilization ratio (FUR)
o May need reach assessment
Structure Size
o Confined: apply a factor of safety
o Unconfined: Compare velocity of natural channel to channel velocity within proposed bridge. Ratio ~ 1
Freeboard
o 3 feet during 100-year event
Source: WDFW WCDG 2013
Source: WDFW WCDG 2013
H&H Analysis
Modeling
o 1-D HEC-RAS
o SRH-2D
Hydraulic Results used for
o Scour Analysis (HEC-18)
o Proposed Streambed Material Size
o Habitat Design
o Compliance with Design Criteria
Hydrology
o Available Gage Data
o USGS regression equations
o Flood Insurance Study
o Climate Change
Proposed Streambed Material
Proposed Gradation
o Match existing channel material (if in equilibrium) based on D50.
o Designed for stability of D84 during 100-year event using modified shields approach or unit discharge method.
o Proposed mix designed by combining WSDOT standard materials using a “Scoop Ratio.”
Olsen Creek – Confined Bridge Example
Olsen Creek – Confined Bridge Example
Olsen Creek – Existing Site Conditionso Existing Culvert – Twin 6-ft
Concrete Pipes
o Existing BFW = 24 ft
o Confined System (FUR<3)
o Constraints: Tidally Influenced, Road on Upstream Right Bank, House on Immediate Downstream Right Bank, Large Conifers
Olsen Creek – Bankfull Width?
March 2016 May 2016
Olsen Creek – Bankfull Width?
Olsen Creek – Tidal Influence
Olsen Creek – Pebble Count Locations/Reference Reach
Olsen Creek – Proposed Designo Proposed BFW = 24 ft with
32 ft Minimum Section
o FOS = 1.33
o 45’ Opening Chosen in Negotiation with WDFW to Allow for Tidal Processes
o FOS = 1.88
o Habitat Features included Large Wood
Olsen Creek – Proposed Plan
Olsen Creek – Proposed Section
BEFORE: D50=1.4 in, D84=3.1 in
AFTER: D50=1.5 in, D84=4.1 in
Olsen Creek – Streambed Material
50% Streambed Sediment, 35% 6in Streambed Cobble, 15% 8in Streambed Cobble
BEFORE
AFTER
Olsen Creek - Structure
Lessons Learned
o Important to obtain concurrence from all stakeholders on bankfull width.
o Minimum bridge opening width of 32 feet based on riverine hydraulics did not account for tidal processes. Based on Neah Bay tidal data, upstream channel only influenced by very high tides, but Neah Bay tidal data may not perfectly represent site.
o Habitat features are located in the field by Engineer during construction. Stakeholders should be present during placement if possible.
