CIVE 6361 – LAB 2: HEC-HMS (Spring 2010)
• Become familiar with HEC-HMS and the basic components of the model
• Understand the organization of the model
• Recognize the different hydrologic elements included in the model and the calculation
methods for each one
• Be able to run a simple model
• Identify the capabilities of the model
• Learn how to import meteorological data into the model by using DSS– Data Storage
HEC-Hydrologic Modeling System (HEC-HMS) is a program designed by the US Corps of
Engineers to simulate surface water hydrology. It includes several hydrologic components that
represent rainfall, evaporation, and snowmelt. There are subroutines for the calculation of
infiltration, losses, base flow, and run-off and different methods for the calculation of each one.
Additionally, HEC-HMS offers different analysis tools to better visualize and understand the
Because of its numerous choices in the methods used for the calculation of run-off and
other hydrologic elements, the challenge for the modeler is to use the most appropriate
methods for the estimation or calculation of required parameters.
Figure 1. HEC-HMS representation of Watershed Runoff
1. Go to the website: http://www.hec.usace.army.mil/software/hec-hms/download.html
2. Go to : HEC-HMS 3.4 for Windows (65.8 MB)/Primary Download Site
3. Save it in your folder and run it.
4. After the installation in complete, go to help and install sample projects. You may use
these as a reference.
1. Go to the website: http://www.hec.usace.army.mil/software/hec-dss/hecdssvue-
2. Go to : HEC-DSSVue 2.0 for Windows (66.5MB) /Primary Download Site
3. Save it in your folder and run it.
PROGRAM LAY OUT
Open the program and take few minutes to explore it.
Figure 2. HEC-HMS interface
MAIN COMPONENTS OF A WATERSHED MODEL
Basin model gives the physical description of the watershed.
a. Sub basin: watershed catchments where rain falls.
b. Reach: rivers and streams.
c. Reservoir: dams and lakes.
d. Junction: confluence.
e. Diversion: bifurcations and withdraws.
f. Source: springs and other model sinks.
g. Sink: outlets and terminal lakes.
Meteorologic model describes atmospheric conditions over the watershed land surface.
b. Potential evapotranspiration.
Control specifications: Time control during a simulation run.
MODELING PROCESS IN HEC-HMS
Import it manually or DSSValue
Define Methods to calculate
Losses, Runoff and Base flow –
Define required parameters
Figure 3. Schematic of the modeling process in HEC-HMS
EXAMPLE #1. The simplest case: A 200-mi watershed has a Lag time of 100 min. Base
flow is considered constant at 20 cfs. The watershed has a CN of 72 and 30% of imperviousness. Use
HEC-HMS to determine the direct runoff for a storm using SCS Unit Hydrograph method.
Precipitation data is presented in Table 1.
Table 1. Precipitation data
DATE 01Jan2000, 00:00 01Jan2000, 03:00 01Jan2000, 06:00 01Jan2000, 09:00 01Jan2000, 12:00
INCREMENTAL RAINFALL (in) 0 0.2 0.5 0.5 0.2
1. Open HEC-HMS 3.3
2. Create a new project. 3. Create all hydrological components.
4. Create sub basin and define methods. 5. Met. Model and Precipitation Time Series
5. Create control specifications 6. Create and compute simulation run
6. View Results 7. Optimization of results
EXAMPLE #2. Example 5.1 in Bedient, Huber, and Vieux
IMPORTING METEOROLOGICAL DATA USING DSS Data Storage System:
Meteorological time series can be imported manually or through the use of DSS Data
Storage. DSS is a file format that is used for storing time series data (such as precipitation and
discharge over time) and other types of data (such as unit hydrographs, elevation-area curves,
and elevation-discharge curves). DSS files store one or more blocks, or records, in a single file
with the “.dss” extension. Each record in the file has header information that identifies the
units, start date, and/or start time of the information in the record. Each record is identified by
a unique identifier called the “pathname”. A path name consists of six different parts separated
by slash (/). The description of the parts is presented in table 1.
Table 2. Pathnames for DSS files
A Project, river, or basin name /A/B/C/D/E/F/
C Data parameter /RED RIVER/BEND MARINA/
D Starting date of block, in a 9 character military format
E Time interval
F Additional user-defined descriptive information
UPLOADING DATA FILES TO DSS
The meteorological data series needed for the development of you project are rainfall data
series and observed flow data for the years 2001 and 2004.
This exercise will be done for observed flows. You will complete the DSS file with rainfall data
DOWNLOADING AND ORGANIZING FLOW DATA
This part of the exercise is similar to the previous laboratory, but with the difference that here
you are going to use simple access tools to covert 15-min data to 1 hour flow data.
1. Go to http://waterdata.usgs.gov/tx/nwis/current/?type=flow
2. Select the site 08075400 (Flow gage that you will use to evaluate model
3. In the top of the website “Available data for this site” select “ Offsite: USGS
Instantaneous-data archive” A
4. Select time frame, save to file as a text file (.txt) in your folder
5. Drag the text file to excel, delete non necessary data (first 65 rows and row 67) and
transform data to two columns: Date (year/month/day)-hour, and value. To get
values for year, month, day, hour, min, and sec you can use the functions LEFT, MID
AND RIGHT. With these two columns you can calculate hourly average flow in
access. Save these columns in a different spreadsheet.
6. Open access and import file from excel (the spreadsheet with two columns)
7. Follow the steps in Access to import the data. Among the instructions you will have
First row contain column settings
No primary key
8. After having data imported, create a query (query Design), select the two columns,
and group value by average.
9. Run the query and save it and export it to excel file and save it as an Excel File 97-03.
UPLOADING DATA TO DSS
1. Open DSSVue 2.0
2. Create a new file
3. Go to the top toolbars and select Data entry/Import Excel
4. Go to the file, select the data you want to import, and click import.
5. File the gaps of the path according to Table 1, and click import.
6. The data have been imported.
1. Exercises 5.1 to 5.6, and 5.8. Hand in the HEC-HMS files with the models. Graphics with
analysis in a separated sheet.
2. Complete DSS file with rainfall and observed flows for the years 2001 and 2004