HEC-HMS

Overview

HEC-HMS (Hydrologic Modeling System) is designed to simulate the complete hydrologic processes of dendritic watershed systems. This is essential in the CWMS software suite, as it fundamentally transforms precipitation and snowmelt into runoff within USACE watersheds. HEC-HMS provides necessary data for HEC-ResSim and HEC-RAS model computes. 

Funded Activities

Accomplishments

Snowmelt Modeling Workshop

A Snowmelt Modeling workshop was held at HEC in the beginning of FY24 with approximately 20 people in attendance. Good feedback was received from those that attended, and suggestions from the workshop are being implemented in FY25. 

Technology Transfer - New Tutorials and Webinars 

The team hosted a webinar on HEC-HMS calibration tools in February 2024 for the CWMS modeling community. New tutorials are in development, such as Parameterizing Gridded Basin Methods. 

Technology Transfer - Field Support

The team provided field CWMS/HEC-HMS related field support to district water management staff in FY24 on an as-needed basis. 

Testing HEC-HMS 4.12 and 4.13 in the CAVI (CWMS 3.4)

Testing was performed to ensure that there was compatibility between HEC-HMS and CWMS to help limit issues users might encounter. 

Fix Bugs

Numerous bugs were fixed that impacted CWMS users, such as several HEC-HMS Error 10000, paired data getting deleted in select cases, and files becoming corrupt. 

Automate Optimization for Forecast Alternatives (CWMS 3.5)

A minimally viable product is on track for end of FY24. This will allow users to utilize HEC-HMS's optimization methods in a Forecast. In doing this, HEC-HMS will give the users a starting point for their model; therefore, decreasing the time it takes to fully calibrate the forecast alternative. 

Improvements for Save As Functionality (CWMS 3.4)

This improvements was largely focused on the terrain file management in saving a model (creating a CWMS forecast). In prior versions, the terrain would be copied with each forecast creation. Now, the terrain files are not transferred with each new forecast created. There is also a checkbox feature in standalone HEC-HMS that allows the user to copy the terrain files if desired. 

Streamline Workflow to Define Parameters with Expression Calculator (CWMS 3.5)

A major refactoring of the HEC-HMS code base has been completed. Gridded editors have been developed and can be modified via global editor which integrates the expression calculator. Code review and implementation are in progress. 

Cloud Compute Enhancements (HEC-HMS API) (CWMS 3.5)

This work ensures that various API calls that are needed to help CWMS run in the cloud are present within HEC-HMS. 

Integrate SnoPac Parameter Estimation Tool into HEC-HMS

The SnoPac functionality has been added to HEC-HMS along with various improvements to the tool. Testing, review, and documentation will be completed in FY25. 

Ensemble Generation (HQ funding)

The team worked out some issues with ensembles and prepped HEC-HMS ensemble to be ingested into CWMS. At the end of the FY, integration of HEC-HMS ensemble compute was in progress. 

Monthly working sessions on Microsoft Teams

The MMC hosts monthly working sessions on the CWMS Modeling Group within Microsoft Teams, allowing HEC-HMS modelers to get support from experts. These sessions are a valuable way to provide field support, answer questions, and demonstrate important capabilities of the software to attendees. Several sessions were focused on demonstrating and/or discussing various topics to disperse knowledge among modelers.