Download the data file here: 3DAY_Obs_Data.dss

Create a New HEC-SSP Study

The first step in performing a frequency analysis within HEC-SSP is to establish which directory you wish to work in and to enter a title for the new study.

  • Create a new HEC-SSP study.
  • Name the study “Sayers_Dam” and provide an adequate description.
  • Leave the Unit System and Coordinate System set to their default values of English and Geographic, respectively.

Import Data

Once the study has been created, you must import the previously mentioned AMS and daily average inflow time series.

  • Click Data | New | Using Import Wizard…
  • Do not modify anything on the first panel.
  • Click the Next button.
  • Select HEC-DSS as the source location and click the Next button.
  • Within the Selected DSS File row, click the ellipsis button, as shown below.

Selecting a DSS File in the Data Importer

  • Navigate to the “3DAY_Obs_Data.dss” file.
  • Select both the SAYERS and PENNS CREEK records that are contained within this file by double left-clicking on each time series to add them to the window at the bottom of the Data Importer.
  • Click Next and review your data one last time.
  • When ready, click Import to to import the data sets and return to the main HEC-SSP desktop.
  • Click the Save button () to save the study.
  • You should notice that two new records were added to the Study Explorer window under Data that contain the 3-day annual maximum series for both Sayers Dam and Penns Creek.
  • Select both data sets using by holding the shift key and left-clicking.
  • Select Data | Plot. A plot containing both data sets should be presented that resembles the following figure.

Sayers and Penns Creek 3-day Flow Time Series

Continue to Task 3. Use the Record Extension Analysis to Extend the 3-day Duration Inflow Data Set.