1. Pool and Chute Fishways
Presented to:
Pacific Northwest Fish Screening
& Passage Workshop, 2006 Yakima, WA
Presented by:
Patrick D. Powers P.E.
September 13, 2006

2. What is a Pool and Chute Fishway?
Hybrid type fishway that operates in two flow regimes, plunging and streaming flow

3. Background Carpenter Creek – Pool and Weir Fishway
Rainbow Creek – Pool and Weir Fishway
WDFW Model Study
Town Dam Pool and Chute Construction
California

4. Pool and Chute - Definition
Side Walls
Baffle Baffle
Weir
Port
Floor

5. Pool and Chute - Cross SectionW
Xpc d Pb b Pw

6. Pool and Chute – Profile – Plunging Flow
SoL Pw So L

7. Pool and Chute – Profile – Streaming FlowPb So L

8. Equations
Flow over a weir
Open channel flow Chezy Eq.

9. Research on streaming/plunging flow regimes
Rajaratnam, N. and Katopodis C Plunging and Streaming Flows in Pool and Weir Fishways. Journal of Hydraulic Engineering 114:

10. Streaming/Plunging Flow Regimes
Transition
Plunging
Streaming

11. Streaming/Plunging Flow Regimes
High Flow - Flood
Streaming

12. Streaming transition flow calculations
Example: b = 2 ft L = 6 ft
So = 10% Qst = 4 cfs
So = 15% Qst = 6 cfs
So = 20% Qst = 8 cfs

13. Case Studies - Parameters

14. Case Studies - Results

15. Fairchild Trib Q = 44 cfs D = 1.75 ft Qt = 5.3 cfs Chezy C = 31.5
Xpc = 1.2
EDF = 2.4
Passage Rating
Fair

16. Fairchild Creek Q = 27 cfs D = 1.65 ft Qt = 5.3 cfs Chezy C = 20.5
Xpc = 1.6
EDF = 2.1
Passage Rating
Good

17. Percival Creek Q = 24 cfs D = 1.5 ft Qt = 5.3 cfs Chezy C = 22.3
Xpc = 1.5
EDF = 1.3
Passage Rating
Fair

18. Fairchild Comparison – 12 Foot Wide
44 cfs: EDF = 2.4
29 cfs: EDF = 2.1

19. Chezy C vs Qst

20. Design Criteria
Xpc = Fish Passage Corridor - 0 to 2 ft
EDF = 2 to 3

21. Design Process Calculate Qfp Select: W, baffle slope, drop, L, b, Pw
Calculate: Qst
Select d and C
Trial and error until Q = Qfp
Check: EDF, Xpc

22. Benefits Reduced or No false attraction (small streams)
Self cleaning (gravel/small cobbles)
Diverse passage routes for adult and juveniles
Pool sizes can be reduced

23. Limitations
Number of weirs fishway length
Alignment
Roughness values

27. Existing Design Guidelines
Draft in Progress - Pool and Chute Fishways
Discussion and Design Process
Revised September 11, 2001
By: Patrick D. Powers, P.E.
Design Spreadsheet