Identify the HEC-ResSim Alternatives

  1. Start the CAVI in local mode.

  2. Open the Workshop_HEC_RussianRiver watershed.  

  3. Open to the Setup tab.
  4. Expand the ResSim node in the Project Tree to see the HEC-ResSim alternative that has been imported into the watershed.

What HEC-ResSim alternative has been imported?

RT-Normal (N)

Open the Forecast

  1. Switch to the Modeling Tab
  2. From the Forecast menu, select "Open"
  3. Open the HEC-ResSim in CWMS Forecast

Check the Model Linking

  1. From the Forecast menu, select Model Linking …
  2. Since this is the only forecast open the No Future Rain forecast is already selected as the Forecast Run from the dropdown.
  3. From the Model Requiring Input: dropdown, select ResSim-RT-Normal.
    1. Have all the Known Flow inputs needed by the HEC-ResSim model been associated with (mapped to) an HEC-HMS output? If not, complete the setup for this model alternative.
  4. What are the Lookback Elevations and Releases Linked to? Does this make sense?

    The Lookback Elevations and Lookback Releases receive input from the Extract List. This is required observed data before the time of forecast, and is usually extracted directly from the CWMS database. 

  5. Although the Model Linking Editor is good at finding the right location for most of the local flows (Known Flows), it sometimes gets the parameter wrong – especially for FLOW-LOCAL (or Local Flow). The local inflows needed by the HEC-ResSim model have been carefully named to indicate whether FLOW or FLOW-LOCAL is needed.
    1. Hint: use the Location column within the Model Linking Editor to help determine whether the flows from HEC-HMS should be Flow or Local Flow.
  6. Verify that all the rows in the table whose Parameter is Known Flow are set to get their input from HEC-HMS. Then, for these same rows, verify that where the model is looking for FLOW-LOCAL, it is getting Local Flow from HEC-HMS.

    1. Were any local flows improperly mapped? What would the consequence of this be?

      Yes, the Hopland Gage FLOW-LOCAL was incorrectly mapped to the Hopland Gage - Flow.

      If this was not corrected, instead of only local flow added to the Hopland Gage, the total flow at the Hopland Gage would be added. 

  7. Save your changes and close by clicking Apply in the Model Linking Editor. (Selecting OK also saves and closes the editor.)

    1. NOTE: You were not asked to change the Input From column for the rest of the rows listed for the HEC-ResSim Alternative in the Model Linking Editor. Should they remain set to Extract List and if so, why?

      Yes. HEC-ResSim requires lookback elevations and releases to set the initial conditions for the reservoirs at the start of the forecast. This lookback data is typically observed data extracted from the CWMS database.

      Also, any entries whose parameter begins with “Obs” are optional observed data that can be used as a comparison to the computed HEC-ResSim results.

  8. Close the Model Linking Editor.

Compute the Forecast

  1. Compute the forecast through HEC-ResSim.

Was your compute successful?

No

If not, which model alternative failed? Why did it fail? What was the error message? What caused that error message? 

The HEC-ResSim model alternative failed

ERROR: Data is undefined or missing on 6 January 2017, 13:00
ResSim Time Series location: Coyote-Controlled Outlet
dssfile C:/CWMS_Class/forecast/HEC-ResSim_in_CWMS/Workshop_HEC_RussianRiver/forecast.dss
dsspath /RUSSIAN/COYOTE/FLOW-OUT//1HOUR/CDEC/
param Flow-RELEASE
timewindow 06Jan2017 0600 16Jan2017 0600
 
ResSim ERROR: Failed to load time-series records
ResSim ERROR: Failed to compute regulated flows
TEXT

This messages indicate that the expected lookback data does not exist at the time stated. At compute time, the alternative is looking for that data in the forecast.dss file, so if the data is not there, it did not get extracted. After reviewing the RUSSIAN/COYOTE/FLOW-OUT//1HOUR/CDEC pathname in the forecast.dss file, it is missing data during the Lookback period. Since this is a required input for ResSim (Reservoir Lookback Release) the ResSim alternative failed.

Revise the Extract groups to include the HEC-ResSim lookback data

To correct the compute error in your forecast, you need to re-extract the needed record for the lookback period. 

  1. From the Forecast menu, select Extract…
  2. Select only the Observed Time Series group to re-extract and click Run Now.
  3. Compute the forecast.

Did your forecast run compute successfully?

Yes

Upon a successful compute: what was the pool elevation for each reservoir at time-of-forecast?

Coyote (Lake Mendocino):         744.14 ft

Warm Springs (Lake Sonoma):   463.24 ft

How did you determine these values? (What plot, report, or tool did you use?)

Release Decision Report for each reservoir.

Prior Task(s):

Current Task:

Task 1: Integration of an HEC-ResSim Model Alternative

Next Task(s):

Task 2: Real-Time Operations with HEC-ResSim