A free, hands-on tutorial for setting up and running HEC-HMS, the Hydrologic Engineering Center's Hydrologic Modeling System. The first two videos take you through a full model from start to finish and then through optimizing it against an observed hydrograph. The rest fills in the supporting workflows: soil data, land cover, Curve Numbers, NOAA Atlas 14 rainfall, and Unit Hydrographs.
HEC-HMS, short for Hydrologic Modeling System, is the U.S. Army Corps of Engineers' Hydrologic Engineering Center software for watershed modeling. It simulates how water moves through rivers and streams in response to rainfall and other inputs, and it underpins a lot of flood-forecasting, water-supply, and floodplain-management work. Everything below is free to use; the data sets needed for the two main lessons are linked alongside each video.
Each video covers a complete workflow. Together they take you from a blank HEC-HMS project to a calibrated model.
A full walk-through of building an HEC-HMS model end to end. We cover data requirements, watershed delineation, model setup, hydrologic methods, control specifications, the model run, and how to read the results. Useful as a first introduction and as a refresher.
How to set up an HEC-HMS model and then optimize it against an observed streamflow hydrograph.
The pieces that come up while you build an HEC-HMS model: getting the input data, computing Curve Numbers, picking the design storm, and the theory behind Unit Hydrographs.
How to download and pre-process SSURGO soil-texture data for hydrologic and watershed modeling. Soil characteristics drive infiltration and runoff, so getting them right early pays off later.
A step-by-step walk-through of getting and preparing NLCD land use and land cover data for hydrologic and watershed analysis.
How to use ArcGIS Pro and ArcHydro together to build a Curve Number raster for your study area.
The Curve Number method estimates stormwater runoff from land use, soil type, and antecedent moisture conditions. It is widely used in stormwater management, flood control, and watershed modeling. Values come from established tables; this video shows how to compute a CN map from those tables in ArcGIS Pro using the built-in tools.
The NRCS (formerly SCS) Curve Number method is an empirical approach for predicting rainfall excess and infiltration. The four videos below build the theory; watch in order.
How to download NOAA Atlas 14 rainfall-frequency estimates from the Precipitation Frequency Data Server (PFDS) for hydrologic and watershed modeling. Choosing the design storm is one of the first steps in a hydrologic study.
A two-part series. Part 1 covers the theory and assumptions behind Unit Hydrographs. Part 2 shows how to build and use one in a modeling project.
Questions on a specific step, or a request for the next video on the channel? Email me. More tutorials and the Python course are on the tutorials page, and recorded course lectures are on the teaching page.