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CA DWR Workshop: POST-WILDFIRE DEBRIS FLOW MODELING APPLICATIONS WITH HEC-HMS & HEC-RAS
CA DWR Wildfire Workshop
October 30 - November 2, 2023
HEC, Davis, CA
Course Objectives
The U.S. Army Corps of Engineers (USACE) Hydrologic Engineering Center (HEC) has added debris yield and flow capabilities to its popular hydrologic and hydraulic software. HEC’s Hydrologic Modeling System (HEC-HMS) can now compute debris yield/flow and the River Analysis System (HEC-RAS) can simulate the non-Newtonian fluid physics of mud and debris flows associated with post-wildfire events and mine-tailing dam breaches. A four-day training is being offered that covers hands on application of debris simulation capabilities in both HEC-HMS and HEC-RAS.
It is recommended that you use HEC-HMS version 4.12 beta 1 or higher version, HEC-RAS version 6.3.1, and HEC-DSSVue version 3.3.24 for the class. You do not need administrative privileges to install HEC-HMS and HEC-DSSVue. Download HEC-HMS version 4.12 beta 1 or higher version from this page, https://www.hec.usace.army.mil/software/hec-hms/downloads.aspx. Download HEC-DSSVue version 3.3.25 from this page, https://www.hec.usace.army.mil/software/hec-dssvue/downloads.aspx. Then use 7-zip and unzip the files to the C:\Programs directory on your computer (you should have a folder named HEC-HMS-4.12-beta.1 within the C:\Programs directory). Then you can pin HEC-HMS.exe and HEC-DSSVue.exe to your taskbar and open these programs by clicking on the icons. You do need to install HEC-RAS 6.3.1 using the app portal - https://app-portal.usace.army.mil/ESD/Loader.aspx?q=webext&f=sccm.
Instructors
Jay Pak
David Ho
Stanford Gibson
Alex SanchezCameron Ackerman
Pre-Read/Watch
Please watch or read these materials before the class.
- Hydrologic Modeling and Debris Flow Estimation for Post Wildfire Conditions
- Hydrologic Modeling with HEC-HMS (2022)
- If you have never used HEC-RAS 2D this class jumps right into the non-Newtonian application of 2D RAS. You may want to take some time to familiarize yourself with this online class: https://www.hec.usace.army.mil/confluence/rasdocs/rastraining/latest/hec-ras-classes/2d-unsteady-flow-2021
Day 1
Time | Duration (min) | Module | Topic | Description | Primary Instructor |
8:00 - 8:30 | 30 | Admin | Welcome, Goals, Class Structure | Matt, Kristy, Jay, Stanford, and MD Haque (DWR) | |
8:30 – 9:30 | 60 | Lecture 1 | Overview of Hydrologic Modeling with HEC-HMS | Discussion about model calibration, Frequency Storm and Hypothetical Storm development, and continuous simulation | David |
9:30 – 9:45 | 15 | Break | |||
9:45 – 11:45 | 120 | Workshop 1 | Simple Model Frequency Storm | David | |
11:45 – 13:00 | 75 | Lunch | |||
13:00 – 13:20 | 20 | Workshop 1 Review | |||
13:20 – 14:30 | 70 | Lecture 2 | Overview of Post-Wildfire Hydrology and Debris Flow Modeling Applications | Discussion of the ways post-wildfire hydrology and debris yield modeling is used in studies including post-wildfire assessments, debris yield prediction, and post-wildfire flow risk and emergency management. | Jay |
14:30 – 15:25 | 55 | Lecture 3 | Subbasin Debris Yield Analysis | Introduction to five debris yield methods for debris yield assessment in burned mountain watershed. Discussion of appropriate use and parameter estimation. | Jay |
15:25 – 15:40 | 15 | Break | |||
15:40 – 16:40 | 60 | Workshop 2 | Quick Debris Yield Modeling based on Field Data | Estimate the parameters for each debris yield method. Enter the initial parameter values within a basin model, create a simulation run, and compute the simulation. Calibrate and compare results to measured sample data. | David and Jay |
16:40 – 17:00 | 20 | Workshop 2 Review | David |
Day 2
Time | Duration (min) | Module | Topic | Description | Primary Instructor |
8:00 – 8:15 | 15 | Admin. | Review previous day and go over goals for today | Jay | |
8:15 – 9:00 | 45 | Lecture 4 | Debris Reservoir Routing Analysis | Explanation of the physical reservoir volume reduction processes at reservoir. The reservoir sediment trap efficiency is affected by the detention time of storm runoff and by factors governing sediment particle size. | Jay |
9:00 – 10:30 | 90 | Workshop 3 | Estimating Debris Yield in Debris Basin | Practice calibrating debris yield modeling without/with Debris Reservoir/Basin and compare results with measured data. | David and Jay |
10:30 – 10:45 | 15 | Break | |||
10:45 – 11:05 | 20 | Workshop 3 Review | Estimating Debris Yield in Debris Basin | Practice calibrating debris yield modeling without/with Debris Reservoir/Basin and compare results with measured data. | David |
11:05 – 12:00 | 55 | Lecture 5 | Debris Channel Routing Analysis | Introduction of the new debris transport potential method (Sediment Delivery Ratio) and debris routing method (Muskingum) to erosion and deposition processes in the channel. | Jay |
12:00 – 13:00 | 60 | Lunch | |||
13:00 – 14:00 | 60 | Workshop 4 | Debris Flow Modeling using Debris Channel Routing Method | Finalize HMS debris flow model using debris methods in subbasin, and channel elements. Calibrate and compare results to measured sample data. Task 4: Debris Flow Modeling using Debris Channel Routing Method | David and Jay |
14:00 – 14:20 | 20 | Workshop 4 Review | Debris Flow Modeling using Debris Channel Routing Method | Finalize HMS debris flow model using debris methods in subbasin, and channel elements. Calibrate and compare results to measured sample data. | David |
14:20 – 15:00 | 40 | Lecture 6 | Post-Wildfire Hydrologic Analysis | Explanation of a surface dynamic infiltration loss method to develop a long-term post-wildfire hydrologic model for a burned watershed. Discussion of the physical basis for the parameters and procedures for post-wildfire effect. | Jay |
15:00 – 15:15 | 15 | Break | |||
15:15 – 16:25 | 70 | Workshop 5 | Post-Wildfire Hydrology Analysis using Surface Dynamic Infiltration Loss Method | Use a surface dynamic infiltration loss method to estimate parameters for the long-term post-wildfire hydrology model. Practice calibrating model and compare results with observed flow (gage data). Applying the Pak and Lee Dynamic Surface Method for Post-wildfire Hydrologic Modeling Parameterize the Dynamic Surface Method and Compute a Simulation Calibrate the Dynamic Surface Method Parameters Comparison of Post-fire Simulations with and without Dynamic Surface | David and Jay |
16:25 – 16:45 | 20 | Workshop 5 Review | David | ||
16:45 – 17:00 | 15 | Group Discussion | Jay and David |
Day 3
Time | Duration (min) | Module | Topic | Description | Primary Instructor |
8:00-8:45 | 45 | Lecture 1 (3.1 L) | Modeling Mud and Debris Flows with HEC-RAS | Overview of non-Newtonian applications of HEC-RAS, including lab and prototype scale studies. | Stanford |
8:45- 9:30 | 45 | Lecture 2 (3.2L) | Overview of HEC-RAS | Introduction to the basic components and workflow of an unsteady, 2D, “blue water” (no debris) HEC-RAS model. | Stanford |
9:30-9:45 | 15 | Break | |||
9:45- 11:30 | 75 | Workshop 1 (3.3W) | 2D Hydraulic Modeling with HEC-RAS | Students build a simple HEC-RAS model. | Stanford Alex Cam |
11:30– 12:30 | 60 | Lunch | |||
12:30-13:30 | 60 | Lecture 3 (3.4L) | Introduction to Non-Newtonian Physics | Introduces the internal stress term in the hydraulic equations and the rheological models that estimate it. | Stanford |
13:30-13:45 | 15 | Quiz Game (3.5Q) | Non-Newtonian Mechanics | Review the Non-Newtonian Physics covered in the previous talk. | Stanford |
13:45-14:30 | 45 | Workshop 2 (3.6W) | Expedited Debris Flow Modeling in HEC-RAS | Build a non-Newtonian debris flow model from a single shape file. | Stanford Alex |
14:30-14:45 | 15 | Break | |||
14:45-15:45 | 45 | Workshop 2 | Continued | Solution Files | Stanford |
15:45-16:45 | 60 | Talk 4 (3.7L) | 2D Hydraulic and Subgrid Best Practices and Troubleshooting | Introduces best practices for developing a stable 2D hydraulic model in steep terrain. | Stanford |
16:45-17:00 | 15 | Quiz Game (3.8Q) | Mesh Doctor Game | Competitive game where students identify problematic meshes and/or potential fixes | Stanford |
Day 4
8:00-9:00 | 45 | Workshop 3 (4.1W) | Model Refinement and Stability Workshop | Students will rerun workshop 2 with the full SWEs and work on the mesh and time step to improve stability. | Stanford Alex |
9:00 – 10:30 | 90 | Lab (4.2 Lab) | Non-Newtonian Flow “Race” | Students will mix bulked fluids with non-Newtonian properties to try to get closest to a time goal. | Stanford Alex |
10:30– 10:45 | 15 | Break | |||
10:45-11:00 | 15 | Lab Review | Lab Review | Plot the student mixtures on the ternary diagram and develop some conclusions. | Stanford |
11:00-12:00 | 60 | Lecture 11 | Selecting Rheological Parameters | The most difficult part of most mud and debris models is estimating the Rheological Parameters. This talk will survey the laboratory and modeling literature, introduce some of the established trends, explore the sensitivity of the mudplain extents to some of these parameters, and provide reasonable modeling ranges to help modelers bound their answers. | Stanford |
12:00– 13:00 | 60 | Lunch | |||
13:00-13:15 | 15 | Quiz Game | Parameter Quiz | Students will review different model parameterizations and evaluate them…for points and glory. www.kahoot.it | Stanford |
13:15-13:30 | 15 | Lecture 5 | Urban Debris Modeling | Modeling clogged culverts and bridges with a 2D RAS Model (and common stability issues). | Stanford |
13:30-15:30 | 120 | Workshop 7 (4.6 W) | Final HEC-HMS/ HEC-RAS Modeling Workshop | Start with clear water HMS and RAS models. Add HMS parameters and compute Cv. Use HMS Cv and NN parameters to model debris flow in HEC-RAS | Stanford Alex HMS Team |
15:30-16:00 | 15 | Break | |||
16:00– 16:30 | 30 | Workshop 8 review | Santa Cruz Workshop | Stanford | |
16:30 – 17:00 | 30 | Group Discussion | Class Review and Future Needs | HEC Team | |
