Rainfall Runoff Modeling with HEC-HMS and HEC-RAS

RAS Mapper as a GIS Tool for Terrain and Spatial Preparation

Preparing terrain and watershed data for hydrologic and hydraulic workflows

·       Terrain, projection, imagery, land cover, soils, stream networks, and gage datasets

·       Using RAS Mapper to organize, visualize, and prepare spatial inputs

·       Terrain processing concepts for HEC-RAS and HEC-HMS applications

·       Data quality, resolution, watershed boundaries, and coordinate system considerations

·       Workshop setup and overview of comparison datasets

Setting Up a Basin Model in HEC-HMS

Building the watershed representation

·       HEC-HMS project organization and basin model components

·       Subbasins, reaches, junctions, reservoirs, diversions, sources, sinks, and outlets

·       Parameterizing drainage areas, slopes, lengths, connectivity, and routing elements

·       Importing or entering physical basin data

·       Hands-on basin model setup exercise

Applying Meteorological Models in HEC-HMS

Translating precipitation data into model inputs

·       Meteorological model types and precipitation data sources

·       Design storms, frequency storms, observed events, gridded precipitation, and gage weighting

·       Temporal distribution, time step selection, and missing data considerations

·       Linking meteorologic models to basin models and control specifications

·       Reviewing precipitation inputs and storm event assumptions

Transform, Loss, and Routing Methods in HEC-HMS

Selecting methods that fit the watershed and data

·       Loss methods such as SCS Curve Number, Green-Ampt, deficit and constant, and initial and constant approaches

·       Transform methods such as SCS Unit Hydrograph, Clark Unit Hydrograph, ModClark, and Snyder

·       Baseflow and channel routing method options

·       Parameter estimation, sensitivity, and model limitations

·       Running HEC-HMS simulations and reviewing hydrographs

Direct Precipitation and HEC-RAS Rain-on-Grid Modeling

Applying rainfall directly to 2D hydraulic models

·       Conceptual differences between HEC-HMS hydrograph routing and HEC-RAS rain-on-grid modeling

·       Applying precipitation to 2D flow areas

·       Terrain, mesh, roughness, infiltration, and time step implications

·       Boundary conditions, initial conditions, and model stability considerations

·       Running rain-on-grid simulations and interpreting spatial results

Comparing and Calibrating HEC-HMS and HEC-RAS Results

Using observed data to evaluate and refine model performance

·       Comparing hydrographs, peak flow, runoff volume, timing, depths, and inundation patterns

·       Calibration with stream gage, precipitation, high water mark, and observed event data

·       Sensitivity analysis for loss, transform, routing, roughness, infiltration, and mesh assumptions

·       Communicating uncertainty and documenting modeling decisions

·       Final comparison exercise, questions and answers, and wrap-up

Registration Date/Time:
6/25/2027 09:30am Central Time

Event Dates/Times:

• 6/25/2027  10:00am - 11:30am Central Time
• 7/2/2027  10:00am - 11:30am Central Time
• 7/9/2027  10:00am - 11:30am Central Time
• 7/16/2027  10:00am - 11:30am Central Time
• 7/23/2027  10:00am - 11:30am Central Time
• 7/30/2027  10:00am - 11:30am Central Time

·       Course materials and resources will be distributed through Canvas. Participants should access Canvas after receiving their NetID and watch the email address used during registration for material release dates and pre-course instructions.

·       Participants should confirm access before the first live session, check with their IT department if needed, and monitor spam or junk folders for messages from wisc.edu addresses.

• Instructor

  Krey Price

  Director

  Krey Price is a civil engineer specializing in water resources. Krey is based in Perth, Australia, where he provides consulting and training services in flood modeling. Krey has a master’s degree in hydraulic and coastal engineering from the University of California at Berkeley. Krey’s thirty-year career has included modeling, design, and project management for international flood mitigation projects.

• Program Director

  Adib Amini

·       Use RAS Mapper to prepare terrain and spatial datasets for HEC-RAS and HEC-HMS workflows.

·       Develop a basin model in HEC-HMS using subbasins, reaches, junctions, reservoirs, and outlets.

·       Apply meteorological models and precipitation inputs in HEC-HMS.

·       Select appropriate loss, transform, baseflow, and routing methods for project goals and available data.

·       Apply direct precipitation in HEC-RAS for rain-on-grid modeling and evaluate model setup considerations.

·       Compare HEC-HMS hydrographs and HEC-RAS rain-on-grid results using common workshop datasets.

·       Calibrate and interpret rainfall-runoff results using stream gage, precipitation, and observed event data.