HEC-WAT Known Issues
Last Modified: 2026-04-14 12:01:19.046
The table below contains a list of known issues documented during the testing of HEC-WAT 1.1 or reported by users while using the HEC-WAT 1.1 beta or release candidate versions. A number of these issues are expected to be resolved with updating the core libraries used by HEC-WAT during planned work for HEC-WAT 1.2, or will be easier to resolve with the updated libraries in place.
| Issue Description / Impact | Current Status / Work-arounds | Components |
|---|---|---|
During an FRA compute the model skip rule editor may occasionally fail to set the skip flag. | Need a reproducible example to perform additional testing. | Model Skip Rules |
| HEC-ResSim fails to compute when passed a fragility curve sample without a defined duration. | As ResSim (3.5 or 4.0) requires the use of a script to properly handle the fragility curve outputs, if a duration is not needed, enter any value for the duration in the fragility curve plugin. | Fragility Curve Plugin, HEC-ResSim |
| Hydrologic Sampler data check reports "DSS record does not contain forecast dates" when hydrologic data is entered for years after 3591. | Shift input data to not extend past 3591. | Hydrologic Sampler Bootstrap Method |
| List of events that fail to compute during a Distributed Compute is incomplete as it is overwritten by results from other nodes as they complete. | Distributed Compute plugin needs to be modified to not overwrite this file. | Distributed Compute |
| Hydrologic Sampler using Bootstrap Method with events less than a year long repeats the final value to fill out each year. | Bootstrap method was designed with full year-long events in mind and was not intended for use in this manner. Use of time window adjustments within the simulation should allow running the models for a shorter time span. | Hydrologic Sampler Bootstrap Method |
| Hydrologic Sampler Bootstrap Method reports incorrect source year for synthetic events. This occurs when the events do not line up with the calendar year or water year (Oct 1st). This largely impacts diagnostic outputs but may impact other models and tools that depend on the "EVENT-YEAR" output record. | Hydrologic Sampler UI needs to allow user to define how the numerical year for the synthetic event is determined. | Hydrologic Sampler Bootstrap Method |
| HEC-WAT reports "Failed to save linkage settings" while linking to HEC-FIA, with a NullPointerError in the log. | Needs a reproducible example to perform additional testing. Rebuilding the HEC-FIA model alternative that expects the linked input from HEC-RAS appears to resolve this issue, but changes to the HEC-WAT model linking editor may require rebuilding the simulation as well. | Model Linking, HEC-FIA, HEC-RAS |
| HEC-WAT shows inconsistent projection or coordinate system labels while creating a new study. This results from various terms used for the same projections and the underlying mapping libraries not being consistent. | Plan to revisit this with HEC-WAT 1.2 when newer mapping dependencies have been incorporated. | Mapping |
| Hydrologic Sampler Bootstrap Method produces a random number of years per lifecycle when input data contains missing values and these were not picked up by the data validation tools. | Recommend cleaning up any input used for the Hydrologic Sampler Bootstrap method external to HEC-WAT, removing missing data and clearing the data quality flags from the DSS records. | Hydrologic Sampler Bootstrap Method |
| Hydrologic Sampler precipitation curve sampling method reproduces DSS record type on the input data which can cause it to be incorrectly interpreted or failing to read the data in the HEC-HMS model. | Recommend setting the input shape sets used for the hyetographs to "PER-CUM" type. | Hydrologic Sampler Precipitation Method, HEC-HMS |
| HEC-WAT creates empty watershed folders on other locations on the computer. This appears to be caused by trying to read map files in the watershed that had an absolute pathname used by another user on their computer. | We will resolve this with HEC-WAT 1.2 with updated dependencies. For now, these folders that contain an empty "maps" directory can be safely deleted, as annoying as they are. | Mapping |
.prj files in the terrain folder as the projections for geospatial for HEC-RAS are sometimes found as the RAS .prj file, with HEC-RAS trying to load them as a project. | We recommend not storing the HEC-RAS terrain files within the WAT watershed but in a parallel directory above the HEC-WAT model. Often when HEC-WAT watersheds are shared among users, these terrain files are static and do not need to be changed. In addition to resolving this issue with the .prj file, this lightens the amount of data that needs to be passed between team members. | HEC-RAS terrain files |
| Hydrologic Sampler Bootstrap Method fails to fill leap year gaps during a continuous ("single event") compute. | This problem may present itself depending on the date chosen for splitting water years and the source data used for simulation. If this is present in a model, the Scripting Plugin may be used to fill empty values. | Hydrologic Sampler Bootstrap Method |
| Renaming a simulation causes the simulation to fail to compute, other cryptic errors. | Renaming a simulation after it has been created tends to break links to a number of other model elements. We do not recommend renaming a simulation once it has been created and configured and have disabled this ability in recent WAT builds. We recommend using the default simulation name that combines the alternative and analysis period. | Simulation Editor |
| Hydrologic Sampler setting for "minimum time window between events" does not have an effect. | This issue will be fixed in a future hydrologic sampler version. | Hydrologic Sampler |
| Hydrologic Sampler with multiple locations and stratified sampling will fail to stratify if the location selected is not the first on the list of locations. This appears to be a bug in the process used to generate the correlated sample of return intervals for the Primary Locations where frequency curves are assigned. | Select the location to stratify first when choosing "Primary Locations" for frequency curves. | Hydrologic Sampler |
| Model Skip Rules do not work with HEC-RAS output time series. | HEC-RAS is often the model being skipped with the model skip rules editor, so we have not prioritized this issue. A fix has been implemented in HEC-WAT, but not thoroughly tested. | Model Skip Rules, HEC-RAS |
| Histogram results viewer for Output Variables freezes up, other output variable results viewer may not work at all. | These features depend on the output being written out from each model and computed correctly, making these problems difficult to reproduce. We are working on improving these tools, but recommend that users also perform post-processing with tools of their choice to produce graphics of model results suitable for their purpose. | Output Variables, Results |
| When importing HEC-RAS models into HEC-WAT, the import process hangs up if the HEC-WAT map window is open. | Recommend keeping the HEC-WAT map window closed while importing HEC-RAS models. | Map Window, HEC-RAS, Importer |
| Opening DSSVue from within HEC-WAT or using the DSS selector from the Model Linking Editor does not always open the correct file, if already assigned. | We will address this with WAT 1.2 when we have updated to newer DSS libraries. | Model Linking Editor, DSS |
If multiple .jar files for the same HEC-WAT plugins are added to HEC-WAT, HEC-WAT will load both copies and may produce unreliable or erratic behavior as a result. Typically this happens when users are testing a new plugin and have multiple versions of that plugin being provided. | We are adding code to detect multiple plugins with HEC-WAT 1.2, in the mean time, users should be careful not to add multiple copies of plugins to their HEC-WAT software. We recommend always placing plugin .jar files in the same place to be careful to remove old copies of the plugins when upgrading. | Plugins |
| The order of entries in the Model Linking Editor may appear to randomly re-order themselves when using multiple model alternatives for the same software. Within the code these are stored in an "unordered" list, and we expect to change this in a future HEC-WAT build. | This is a display issue only, and we intend to fix it in future HEC-WAT version. | Model Linking Editor |
| Hydrologic Sampler gives an incorrect error message when a synthetic event "takes up too much space" such as creating a 2% return interval synthetic for use with a historical record of approximately 100 or more years. The message in the compute window says "Data consistency error(s): Settings: Hydrographs: Uncertainty years of record must be positive". | Hydrologic Sampler Bootstrap Method should use "override incremental probability" if the most frequent synthetic event has an annual chance exceedance that is larger than the annual chance exceedance for most rare historical event (by Weibull plotting position). | Hydrologic Sampler Bootstrap Method |
| When computing simulations from the Compute Manager window, not selecting any simulations and clicking compute causes the Compute Manager to freeze. | Always select a simulation before clicking compute. | Compute Manager |
| When selecting existing simulations to copy model linkages from, the Model Linking Editor presents a list that includes deleted simulations. | These deleted simulations were incompletely removed and we will be fixing this in a future version. | Model Linking Editor |
| Renaming model alternatives will cause existing simulations using them to break, often requiring re-linking models, reselecting output variables, and reconfiguring model skip rules. | Do not rename an existing model alternative but use the "save as..." or other feature to create a copy, and then replace the existing model alternative with the new name. | Plug-ins |
| HEC-HMS model disappears from watershed during a distributed compute. | We will fix this in a future build of HEC-WAT or HEC-HMS but have not identified a cause for this issue yet. This only impacts distributed computes with HEC-HMS in the program order for a simulation, and may be caused by specific settings changes in the Distributed Compute plugin. | Distributed Compute, HEC-HMS. |
| HEC-RAS Overwrites Geometry when opened with the "Edit" menu from the right-click (context) menu in the Simulation Pane. This occurs most frequently when a user has multiple HEC-RAS geometries in their watershed. | Recommend using only one HEC-RAS geometry per watershed if possible, or not using this button if multiple HEC-RAS geometries are required for a simulation. This issue also occurs in CWMS CAVI / HEC-RTS and no resolution has been identified yet. We recommend keeping a backup of the RAS geometry files for these studies and updating them whenever geometry edits are made. | HEC-RAS |
| HEC-RAS models fail to run once the lifecycle DSS file grows to greater than two gigabytes due to an internal limitation in HEC-RAS. This occurs when either DSS v6 and DSS v7 files are used. This most often occurs when many timeseries outputs are being produced by HEC-RAS and stored back to the lifecycle file; and mostly on large models (>800 river miles). The HEC-RAS model will fail with the error "Computations were not performed, there must have been some missing data in the input files." | Preferably reduce HEC-RAS outputs to timeseries data or running shorter lifecycles that contain fewer events. We've added a hidden setting to enable HEC-RAS to write model outputs to a different DSS file during the compute. | HEC-RAS |
| HEC-ResSim Output Variables fail to report units. | Units for the Output Variables from HEC-ResSim should be the same as with those in the DSS file for the lifecycle simulation. | HEC-ResSim, Output Variables |
| Scripting Alternative output variables do not work consistently in FRA computes. | We are investigating this issue and plan to implement a fix soon. Some teams are able to post-process their lifecycle simulation DSS files to get the necessary data and are using this as a work around. | Scripting plugin, Output Variables. |
| HEC-RAS reports "user stopped computations" when the model fails for some other reason. This message is misleading. | This requires a change in the HEC-RAS source code that has not been made. This message is fed back into HEC-WAT and thus appears in the HEC-WAT logs. | HEC-RAS, Compute Log |
| Scripting plugin model linking does not consistently pick up new changes. Once configured for one simulation, the scripting plugin appears to stick with the linked DSS pathnames for that first simulation, even when reused in another simulation. | Creating additional copies of the scripting plugin for various input configurations appears to fix this issue but creates problems with model linking in each simulation. We are working to address this issue. | Scripting Plugin, Model Linking |
| Plots opened from within the Hydrologic Sampler editor UI do not allow tabulating or have missing toolbar for the zoom cursor, the view menu options can cause errors in the HEC-WAT console window. | We need to upgrade to newer HEC shared code dependencies to fix this issue and expect to address it in a future version of HEC-WAT. | Plotting, Hydrologic Sampler |