After data has been imported into the study, one or more filters can be applied to create new, modified data sets. For instance, an imported time series of daily precipitation accumulations spanning 1920 through 2018 can be filtered using an absolute time window spanning 1955 through 2010. Also, an annual maximum series can be extracted from a time series of hourly flows using the Annual Maximum filter. Filters can be nested as well. For example, an annual maximum series can be extracted from a time series of daily average reservoir stage for the time period between 1955 and 2010 using a season spanning 01Apr – 30Nov. The resulting annual maximum series would be comprised of peak stages that occurred between 01Apr and 30Nov in each year between 1955 and 2010. Filters that are available for use include:

  • Dates
    • Time Window
    • Season
    • Min / Max Threshold
  • Duration
  • Peaks
    • Annual Maxima
    • Peaks Over Threshold (Partial Duration Series)
  • Starting Pool Stage / Elevation

The previously-imported daily precipitation accumulations at Hawley, PA will be filtered to an annual maximum series as well as a partial duration series.

  • Right click on the "Hawley Daily Precipitation" data set within the Study Explorer and select Filter Data.
  • On the Dates and Threshold tab, take note of the available filters. However, do not select any of them for this example.
  • Move to the Peaks tab.
  • Click the Filter to Annual Maxima check box and enter 01Oct within the Start of Year entry field to specify use of water year. The Filter editor should appear similar to Figure 1.

Figure 1. Filter to an Annual Maximum Series

  • Click the Save Filtered Data Set As button.
  • Within the Save as New Data Set window, enter a name of "HAWLEY 1 E PA US-PRECIP-INC-Filtered-AMS" and an F-part of "AMS". Leave the remaining options unchanged. This window should appear similar to Figure 2.

  • Click OK to save the new data set.
  • Right click on the new data set within the Study Explorer, select Edit Metadata, and edit a Short ID to help identify it as the annual maximum series (e.g. "Hawley_AMS").  Click OK to close the window.
  • Right click on the "Hawley Daily Precipitation" data set within the Study Explorer and select Filter Data.
  • Move to the Peaks tab and click the Filter Data by Peaks Over Threshold (Partial Duration) check box.
  • Enter a Minimum Threshold of 1 and delete the contents of the Duration of time between peaks entry field. The Filter editor should appear similar to Figure 3.

Figure 3. Filter to a Partial Duration Series

  • Click the Save Filtered Data Set As button.
  • Within the Save as New Data Set window, enter a name of "HAWLEY 1 E PA US-PRECIP-INC-Filtered-PDS", a Short ID to help identify it as the partial duration series (e.g. "Hawley_PDS"), and an F-part of "PDS". Leave the remaining options unchanged. This window should appear similar to Figure 4.

Figure 4. Partial Duration Series Data Set and DSS Part Names

  • Click OK to save the new data set.
  • Select the Hawley Daily Precipitation data set in addition to the newly created annual maximum series and partial duration series by holding the Ctrl key and left clicking on each data set. Once the three data sets have been selected, click Data | Plot. A new window will appear containing the two data sets, as shown in Figure 5.

Figure 5. Daily Precipitation, Annual Maximum Series, and Partial Duration Series

  • Click the Save button (  ) to save the study.

Continue to Task 8. Create and Parameterize a Distribution Fitting Analysis.

Download the final project files here: Intro_to_SSP.zip