U.S. Department of Transportation
Federal Highway Administration
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Federal Highway Administration Research and Technology
Coordinating, Developing, and Delivering Highway Transportation Innovations
REPORT 
This report is an archived publication and may contain dated technical, contact, and link information 
Publication Number: FHWAHRT14064 Date: August 2014 
Publication Number: FHWAHRT14064 Date: August 2014 
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The study described in this report was conducted at the Federal Highway Administration's TurnerFairbank Highway Research Center (TFHRC) J. Sterling Jones Hydraulics Laboratory in response to the need for guidance to evaluate the variation of velocity within a culvert crosssection to facilitate fish passage design identified by State transportation departments. The State transportation departments that contributed funding for the realization of this study were Alaska, Georgia, Maryland, Michigan, Minnesota, Vermont, and Wisconsin. A 3ft corrugated metal pipe (CMP) was used during the physical modeling phase of the research study. The results obtained from the physical modeling phase of the study were corroborated during the computational fluid dynamics numerical modeling phase of the study. This report will be of interest to hydraulic engineers and environmental scientists involved in the design of new or retrofit of existing CMPs for fish passage. The report is being distributed as an electronic document through the TFHRC Web site at https://www.fhwa.dot.gov/research/.
Jorge E. PagánOrtiz
Director, Office of Infrastructure
Research and Development
Notice
This document is disseminated under the sponsorship of the U.S. Department of Transportation in the interest of information exchange. The U.S. Government assumes no liability for the use of the information contained in this document. This report does not constitute a standard, specification, or regulation.
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Technical Report Documentation Page
1. Report No.
FHWAHRT14064 
2. Government Accession No.  3 Recipient's Catalog No.  
4. Title and Subtitle
Fish Passage in Large Culverts with Low Flows 
5. Report Date August 2014 

6. Performing Organization Code  
7. Author(s)
Yuan Zhai, Amin Mohebbi, Roger Kilgore, Zhaoding Xie, and Jerry Shen 
8. Performing Organization Report No.


9. Performing Organization Name and Address GENEX SYSTEMS, LLC 
10. Work Unit No. (TRAIS) 

11. Contract or Grant No. DTFH6111D00010 

12. Sponsoring Agency Name and Address
Office of Infrastructure Research and Development 
13. Type of Report and Period Covered
Laboratory Report 

14. Sponsoring Agency Code


15. Supplementary Notes The Contracting Officer's Representative (COR) was Kornel Kerenyi (HRDI50). Steven Lottes and Cezary Bojanowski of the Argonne National Laboratory and Dr. Fred Chang contributed to this research. The Maryland State Highway Administration was the lead State coordinating with FHWA on this research. 

16. Abstract A series of physical and numerical modeling runs were completed to support the development of a design procedure for characterizing the variation in velocity within nonembedded and embedded culverts. Physical modeling of symmetrical halfsection circular culverts was conducted to provide data against which computational fluid dynamics (CFD) modeling could be validated. The initial CFD modeling featured twophase numerical computations that successfully reproduced the physical modeling results. To further simplify, singlephase modeling and truncated singlephase modeling were evaluated with good results. For the embedded culvert runs, a successful strategy for representing natural bed material within the culvert was developed.
Once the CFD modeling was validated by the physical modeling, the CFD modeling was used to analyze the full culvert crosssections. Test matrices included CFD runs scaled up to larger culvert sizes. One series of runs maintained Froude number based scaling and one series tested larger sizes without the scaling constraint. The CFD runs and a velocity distribution model formed the basis of a proposed design methodology for determining the velocity distribution within a culvert crosssection. Using the 42 CFD runs for a 3ft diameter culvert, the 5 parameters necessary for the velocity model were estimated. Then, based on geometric and hydraulic parameters available to a designer, relations were developed to estimate those parameters. The approach was successfully validated on CFD runs for 6ft and 8ft diameter culvert models. The proposed design procedure allows a designer to estimate the velocity throughout a crosssection. These data may be depthaveraged to provide a distribution of velocity and depth across the culvert crosssection that may be used to evaluate fish passage. Although developed for circular culverts, the parameters used in the method are such that the procedure should be applicable to rectangular and other shapes. Two design examples and an application guide are provided to illustrate the method and the required computations. 

17. Key Words
culvert hydraulics, fish passage, velocity distribution, CFD, culvert embedment 
18. Distribution Statement
No restrictions. This document is available to the public through NTIS: 

19. Security Classification Unclassified 
20. Security Classification Unclassified 
21. No. of Pages 134 
22. Price 
Form DOT F 1700.7  Reproduction of completed page authorized 
SI* (Modern Metric) Conversion Factors
2D  Twodimensional 
3D  Threedimensional 
A  Crosssection flow area, ft^{2} (m2) 
ADV  Acoustic Doppler velocimetry 
A_{p}  Surface area of the wetted perimeter (culvert wall and bed), ft^{2} (m2) 
a_{y}  Variable dependent on embedment 
B_{i}  Transverse distance on the water surface to the left (i = 1) and right (i =2), ft (m) 
B_{avg}  Average flow width in the crosssection (half section), ft (m) 
CAD  Computeraided design 
CCD  Charge coupled device 
CFD  Computational fluid dynamics 
CMP  Corrugated metal pipe 
CBC  Concrete box culvert 
CSP  Corrugated structural plate 
d_{e}  Embedment depth, ft (m) 
D  Culvert diameter, ft (m) 
D_{50}  Median grain size, ft (m) 
FHWA  Federal Highway Administration 
Fr  Froude number based on average crosssection velocity and depth (V_{a}/(gy_{a})^{0.5}) 
g  Gravitational acceleration, ft/s^{2} (m/s^{2}) 
HECRAS  Hydrologic Engineering Centers River Analysis System 
M  Velocity distribution parameter 
n  Manning's roughness 
p  Pressure on the flow field at the end of the control volume, lb/ft^{2} (N/m^{2}) 
Δp  Change in pressure from one end of the control volume to the other, lb/ft^{2} (N/m^{2}) 
P_{b}  Wetted perimeter for the bed material, ft (m) 
PIV  Particle image velocimetry 
P_{w}  Wetted perimeter for the culvert wall, ft (m) 
Q  Culvert discharge, ft^{3}/s (m^{3}/s) 
Q_{H}  High passage discharge, ft^{3}/s (m^{3}/s) 
Q_{L}  Low passage discharge, ft^{3}/s (m^{3}/s) 
RANS  Reynoldsaveraged NavierStokes 
Re  Reynolds number based on hydraulic radius (V_{a}R_{h}/v) 
R_{h}  Hydraulic radius, ft (m) 
RMS  Root mean square 
RMSE  Root mean square error 
SPIV  Stereoscopic particle image velocimetry 
T  Top width of the water surface, ft (m) 
u*  Mean shear velocity, ft/s (m/s) 
V  Point velocity, ft/s (m/s) 
V_{a}  Average flow velocity, ft/s (m/s) 
V_{f}  Maximum allowable fish passage velocity, ft/s (m/s) 
V_{i}  Depth average velocity of the i^{th} crosssection slice, ft/s (m/s) 
V_{max}  Maximum flow velocity in a crosssection, ft/s (m) 
VOF  Volume of fluid 
y  Vertical distance from the lowest elevation of the flow field, ft (m) 
Y  Normalized Cartesian coordinate in the vertical direction 
y_{a}  Average flow depth (A/T), ft (m) 
y_{f}  Minimum required depth for fish passage, ft (m) 
y_{i}  Flow depth of the i^{th} crosssection slice, ft (m) 
y_{max}  Maximum flow depth, ft (m) 
z  Horizontal distance from the culvert centerline, ft (m) 
Z  Normalized Cartesian coordinate in the horizontal direction 
β_{i}  Velocity distribution parameter 
δ_{i}  Velocity distribution parameter, ft (m) 
δ_{y}  Velocity distribution parameter, ft (m) 
ε  Velocity distribution parameter, ft (m) 
η  Coordinate axis in the ξη system 
v  Kinematic viscosity, ft^{2}/s (m^{2}/s) 
τ_{w}  Wetted perimeter shear stress, lb/ft^{2} (N/m^{2}) 
ξ  Coordinate axis in the ξη system 
ξ_{0}  Minimum value for the ξ coordinate 
ξ_{max}  Maximum value for the ξ coordinate 