Overview of HEC-HMS software

 History 

The Hydrologic Engineering Center (HEC) of the US Army Corps of Engineers is where the HEC-HMS program was created. A part of the HEC Next Generation Software Development Project is HEC-HMS. Director of HEC Darryl Davis is in charge of this project. Project manager for the HEC-HMS is Arlen Feldman. A group of HEC employees and consultants created the program. The majority of the graphical user interface was created by Elisabeth Pray of HEC, who also combined the different parts to create the finished program. The computation engine and hydrologic algorithm library were created by contractor Paul Ely. HEC employee William Scharffenberg worked on the graphical user interface design, oversaw testing, and wrote the user's guide for the software. The gridded data storage algorithms were created by Thomas Evans at HEC. The graphical user interface for soil moisture accounting was created by contractor Richard Raichle. The graphical user interface for the meteorological model was created by contractor Shannon Newbold. The technical assessments made by Todd Bennett of HEC helped design the soil moisture accounting loss method. HEC's Jessica Thomas carried out tests and created validation documents.

Numerous people who contributed to earlier iterations of the program continue to benefit from it. The development team was overseen by John Peters, a HEC, until his retirement in 1998. He oversaw development at the time, wrote the initial draft of the user's manual, and created the graphical user interface. Tony Slocum, a consultant, and Arthur Pabst from HEC made significant contributions to the program's object-oriented design. Slocum also created the code for the basin model's schematic representation. HEC's William Charley created the computation engine's design. The optimization manager's scope and content were suggested by David Ford Consulting Engineers. The Version 1.0 beta testing team was led by HEC's Troy Nicolini, who also oversaw the initial release. Several University of California.

Introduction

The Hydrologic Modeling System's (HEC-HMS) technical reference manual is available in this document. The Hydrologic Engineering Center (HEC), which produces the program, is a research and development unit of the US Army Corps of Engineers. The program models natural and artificial processes for precipitation, runoff, and routing. The Flood Hydrograph Package HEC-1 (USACE, 1998) and various specialized versions of HEC-1 are replaced and succeeded by the program. The software enhances HEC-1's capabilities and adds new features for distributed modeling and continuous simulation.

The mathematical models that are a part of the program are described in this technical reference manual. The manual also offers instructions on how to use the models, when to use them, and how to calculate a model's parameters.

The engineer or scientist who has studied hydrology in a university-level course is the target audience for the presentation of the models. As a result, common model examples are not given; instead, readers should consult the books and journals that are currently in print. On the other hand, the program includes examples of computations for novel or uncommon models.

Overview of Software

The following elements are provided by the program for precipitation-runoff-routing simulation:

1. Options for specifying precipitation that can be used to describe observed (historical) precipitation events, hypothetical precipitation events based on frequency, or events that represent the maximum amount of precipitation that could fall at a specific location.

2. loss models that, given rainfall and watershed characteristics, can calculate the amount of runoff.

3. Direct runoff models that can take into account the energy losses, overland flow, and storage as water drains from a watershed and enters a stream.

4. Models for hydrologic routing that take energy flux and storage into account as water flows through stream channels.

5. Models of confluences and bifurcations that occur in nature.

6. Models of water-control strategies, such as those involving diversion and storage.

7. A distributed runoff model that can be applied to data on distributed precipitation, such as that provided by weather radar.

8. A model that continuously accounts for soil moisture is used to simulate how a watershed will react over time to wetting and drying.

9. An automatic calibration package that, given observations of hydrometeorological conditions, can calculate a number of model parameters and initial conditions.

Model ??

For a variety of water resource studies, the following activities require the assistance of hydrologic engineers:

Creating new hydraulic conveyance and water control facilities.

• Using current hydraulic conveyance and water control facilities and/or evaluating them.
• Flood preparedness and response.
• Controlling activities in floodplains.

Only very rarely does the historical record of flow, stage, or precipitation provide the necessary information. The information is typically obtained by predicting watershed runoff. For instance, an estimate of the increased volume of runoff due to suggested changes in land use in a watershed may be necessary for a study on flood damage reduction. However, since the change hasn't yet happened, there won't be any records to give this information. Similar to this, if a tropical storm changes course and passes over a watershed, it may be necessary to forecast reservoir inflow to decide when to release water. It is not acceptable to hold off and watch the flow. The other option is to present the information using a model.

A model connects an unknown (the output) to an input (the knowledge). The known input is precipitation and the unknown output is runoff for the models that are part of the program, or the known input is upstream flow and the unknown output is downstream flow.

Models can take many different shapes. Physical models are representations of systems in the real world in reduced dimensions. The Colorado State University lab model of a watershed is an example of a physical model of a watershed. It consists of a sizable surface with overhead sprinklers that simulate the input of precipitation. The surface can be changed to mimic different land uses, soil types, surface slopes, and other features, and the rate of rainfall can be managed. Since the system is closed, the runoff can be measured. Simulating open channel flow is one of a physical model's more frequent applications. Many of these models have been built by the Corps of Engineers Waterways Experiment Station, and they have been used to provide information for addressing queries about flow in intricate hydraulic systems.

 

Analog models that compare the flow of electricity in a circuit to the flow of water have also been developed by researchers. With those models, adjusting the amperage controls the input, and a voltmeter measures the output. Analog models have historically been employed to estimate subsurface flow.