Methods for Evaluating Culverts for Fish Passage

12/20/00


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Table of Contents

Methods for Evaluating Culverts for Fish Passage

Outline

Four Ways to Evaluate Culverts for Fish Passage

Observing Actual Fish Passage Success

Hydraulic Analysis (Mathematical modeling of flow in culverts.)

Velocity Measurements (Detailed measures/mapping of water velocity to find passable zones.)

Measurement of Surrogates (Measuring culvert gradient to estimate water velocities, etc.)

This Class will Focus on Measurement of Surrogates!

Introduction to Measurements

Accuracy, High and Low

Precision

Bias

Precision, Bias, and Accuracy (adapted from EPA 1996.)

Consider the Precision of Your Measurement vs. the Evaluation Criteria!

Take Home Point with Precision of Tools

Ensuring Accuracy and Precision of Measurements

Accuracy, precision and good protocols/methods ensure that you or someone else could perform the same set of measurements and come up with the same result: REPEATABILITY!!

Barrier Analysis Key

Barrier Evaluation Key 1

Barrier Evaluation Key 2

Culvert Evaluations

Step 1: Outlet Drops

Residual Pool Measurements

Residual Pool Measurements

Step 1: Outlet Drops (Jumping)

Outlet Drop Barrier Categories from Key 1

Step 2: Baffle/Weir Designs (Velocity, Jumping)

Step 2: Baffle/Weir Designs (Velocity, Jumping)

Step 2: Baffle/Weir Designs (Velocity, Jumping)

Step 3: Sediment Retention Patterns (Velocity) Full Retention

Sediment Retention Patterns Sparse Retention

Sediment Retention Barrier Categories from Key 1

Average Sediment Depth (pipe capacity losses)

Step 4: Backwatering (velocity)

Backwatered Conditions

Backwatered Conditions

Design of Manmade Downstream Weirs (Jumping)

Backwatering Barrier Categories from Key 1

Step 5: Culvert Gradient (Velocity)

Culvert Gradient Barrier Categories from Key1

Step 6: Inlet Drop (Velocity)

Step 6: Inlet Drop, con’t (Velocity)

Step 6, con’t: Channel Constriction (Velocity)

Step 6: Inlet drops and Channel Constrictions

Step 6, con’t: Channel Constriction (Velocity) Culvert Width/ Bankfull Width

Bankfull Width

Bankfull Width

Culvert Dimensions

Culvert Dimensions

Step 7: Water Depth (Submergence)

Step 7: Water Depth (Submergence)

Step 7: Water Depth (Submergence)

Step 7: Water Depth (Submergence)

Other Factors for Prioritization or Planning

Peak Flow Analysis

Peak Flow Analysis

Peak Flow Analysis, con’t

Channel Gradient

Channel Profile

Valley Fill Depth

Closing Remarks

Author: Marganne Allen

Home Page: Fish Passage Short Course