HEC-HMS Changelog

What's new in HEC-HMS 4.12 Beta 6

• Improved Terrain Data Management
• As of v4.12 terrain data is now managed such that there is only one copy of the terrain, and terrain-derived rasters, per terrain-projection combination. In previous versions, a copy of the terrain data, and terrain-derived rasters, was made for every basin model regardless of whether the terrain and projection were the same. This caused excessive project size on disk, most notably when many copies of the basin model were made, as is the case in forecasting.
• The terrain and terrain-derived files are now located in <project directory>/terrain/<terrain name>/<projection index> location, unless an external reference is made. Pre-v4.12 projects will be automatically migrated, which moves the terrain file from <project directory>/terrain/<terrain name>.elevation.tif to the new terrain directory. Additionally, terrain-derived rasters are moved to the new terrain directory from the <project directory>/gis/<basin name> folder.
• As part of the terrain data management improvements there is now an option to copy terrain data when using Project | Save As to create a copy of the project. If the copy terrain data option is selected a copy of the terrain files will be made in the new project location. If the copy terrain data option is not selected a reference will be made to the terrain files in the original project location.
• This feature was funded by the Corps Water Management System (CWMS) National Implementation Program. Initial code and implementation was done by Tom Brauer. Testing was done by Matt Fleming, Mike Bartles, and Tom Brauer.
• Improved Terrain Data Management when using CWMS/HEC-RTSLink to Improved Terrain Data Management when using CWMS/HEC-RTS
• In previous versions of HEC-HMS, when extracting a "forecast" project from a "base" project within an CWMS/HEC-RTS watershed, all terrain data and terrain-derived data sets (e.g., flow direction, flow accumulation, etc.) were copied to the "forecast" project. Now, the "forecast" project will instead reference the "base" project's terrain data. This improvement will shorten the amount of time necessary to extract a new "forecast" project as well as save disk space.
• This feature was funded by the Corps Water Management System (CWMS) National Implementation Program. Initial code and implementation was done by Mike Bartles and Tom Brauer. Testing was done by Matt Fleming, Mike Bartles, and Tom Brauer.
• Storm Temporal Pattern and Area Reduction Function SamplingLink to Storm Temporal Pattern and Area Reduction Function Sampling
• In v4.11 the ability to sample non-numeric parameters was added in the form of sampling precipitation gridsets. This concept has been extended in v4.12 to allow sampling of a hypothetical storm's storm pattern and area reduction function in the Uncertainty Analysis. A Parameter Value Samples paired data must be created that lists storm patterns or area reduction functions. The paired data must then be referenced as an Uncertainty Analysis parameter.
• The image below shows the "Storm Patterns" Parameter Value Samples paired data selected in the Uncertainty Analysis component editor.
• This feature was funded by the USACE Flood & Coastal R&D Hypothetical Storms work unit. Initial code implementation was done by Thomas Brauer and Natasha Sokolovskaya. Testing was done by Greg Karlovits.
• In v4.11, the Ensemble Analysis compute type was created. In v4.12, the time-series types that are compatible with the Ensemble Analysis have been extended to include sediment load, sediment volume, and bulk flow. Total time-series are available for selection as well as individual grade time-series types.
• This enhancement was funded by the SET program. Initial code implementation was done by Josh Willis. Testing was done by Dr. Jay Pak and Josh Willis.
• Ensemble Analysis ViewerLink to Ensemble Analysis Viewer:
• A Ensemble Analysis Viewer has been added to allow users to view ensembles computed in HEC-HMS and perform metric computes on the ensemble time series. The ensemble viewer can compute metrics as a "Single Summary Time Series", "Single Value for each Ensemble", or a Single Value Summary. The viewer can be accessed through the Tools | Ensemble Viewer. More information on the viewer is described here:
• This feature was funded by the FIRO program. Initial code implementation and Documentation was done by David Ho. Review and Testing was completed by Josh Willis and Tom Brauer.
• Linear Deficit and Constant Loss MethodLink to Linear Deficit and Constant Loss Method:
• The Linear Deficit and Constant loss method is a modification of the initial constant loss method. This method accounts for changes in infiltration capacity (or potential infiltration rate) as a function of cumulative infiltration and can be applied as an event-based or continuous model. This new loss method will compute excess runoff even when the soil is not saturated if the precipitation intensity is large enough. More information can be found in the HEC-HMS Technical Reference Manual, Linear Deficit and Constant Model. An example application is available in the HEC-HMS Tutorials and Guides space, Applying the Linear Deficit and Constant Loss Method.
• This feature was funded by the HH&C General Investigation Hydrologic Studies program. Algorithm development was completed by Dr. Gerhard Schoener, SSCAFCA Senior Hydrologist, code implementation was completed by Paul Ely, and documentation and testing were completed by Gerhard Schoener, Sara Rassa, Matt Fleming Natasha Sokolovskaya, and Tamara Massong.
• This new Uncertainty Analysis method combines the sampling methods of the Random and Specified Values methods. With this method, the sample index order will be random, based on the starting seed value, and all parameters using this sampling method will use the same index.
• The original Specified Values method has been renamed to Specified Values - Random (Independently Random).
• This feature was funded by the FEMA Future of Flood Risk Data initiative. Initial code implementation was completed by Daniel Black. Documentation and testing was completed by Daniel Black and Greg Karlovits.
• Coefficient Time Series and Spatial Results:
• Incoming shortwave (a.k.a. solar) radiation at a location can be reduced due to the surrounding terrain. These effects can lead to snow melting slower within shaded areas. While solar shading was included within previous versions of HEC-HMS, users can now visualize the computed solar shading coefficient a subbasin-average time series or as a spatial result (e.g., at each grid cell) when using either the Gridded Hybrid or Gridded Energy Budget snow methods, as shown below.