Return to Calibrate the Deficit and Constant Basin Model to Observed Annual Maximum Flows

Last Modified: 2024-09-05 17:34:04.625

HEC-HMS Version

HEC-HMS version 4.12 was used to create this tutorial. You will need to use HEC-HMS version 4.12, or newer, to open the project files.

Project Files

If you are continuing from Calibrate the Deficit and Constant Basin Model to Observed Annual Maximum Flows, you may continue to use your current project files. Otherwise, download the initial project files here:

EF_Russian_River_Task_4_Initial.zip

In Calibrate the Deficit and Constant Basin Model to Observed Annual Maximum Flows you calibrated the EF Russian River Deficit and Constant basin model to observed annual maximum flow values at Calpella. In this task you will calibrate the EF Russian River Soil Moisture Accounting basin model.

  1. Open the Russian River project.
  2. Open basin model EF Russian SMA 1951-2010. Notice the EF Russian 20 subbasins uses the Soil Moisture Accounting loss method. View the Soil Moisture Accounting loss parameters in the component editor by highlighting the EF Russian 20 subbasin in the watershed explorer, then select the loss tab in the component editor (Figure 1). As you can see the Soil Moisture Accounting loss method is a more detailed soil loss model compared to the Deficit and Constant loss method. Soil Moisture Accounting represents the soil with three conceptual layers – Soil Storage, Groundwater 1 (GW 1), and Groundwater 2 (GW 2). The Deficit and Constant loss method represents the soil with just one layer.
    Figure 1. Soil Moisture Accounting Loss Method Component Editor
  3. Flow peaks are most sensitive to the Maximum Infiltration parameter for the Soil Moisture Accounting loss method. Maximum Infiltration represents the infiltration capacity of the soil when dry. The infiltration capacity decreases as the soil becomes saturated. Think about how adjusting the Maximum Infiltration parameter might affect peak runoff. For the actual Russian River study, the hydrology model was calibrated to average monthly water volumes and average daily flows prior to calibrating to annual maximum flows. The basin model you will begin with in this task has calibrated canopy, loss, and baseflow parameters that reproduce observed monthly water volumes and average daily flows. The next step will be to calibrate the Maximum Infiltration parameter to reproduce observed annual maximum flow peaks. The parameter value for Maximum Infiltration has been initially set based on soils analysis in a GIS and will be the focus for adjustment during calibration.
  4. Follow the same steps in the Calibrate the Deficit and Constant Basin Model to Observed Annual Maximum Flows tutorial to compute and extract annual maximum peak flows. Use tab "SMA" in the "EF Russian River Compare.xlsx" spreadsheet to evaluate model fit. Adjust the Maximum Infiltration parameter until the slope of the best fit line is 1 ± 0.05. A flow chart of the calibration procedure has been provided in Figure 2. 
    Figure 2. Calibration Procedure for Annual Maximum Flow


The calibrated value for “Maximum Infiltration” is approximately 0.35 to 0.39 in/hr.

Yes, calibrated values from a shorter duration continuous simulation often provide a good indicator for a longer duration continuous simulation. For really long simulations, it may be beneficial to calibrate a shorter duration continuous simulation prior to calibrating for the longer duration. The shorter duration allows the modeler to take advantage of faster run times while familiarizing with the mechanics of the study area and modelling methods.


Project Files

Download the final project files here:

EF_Russian_River_Task_4_Final.zip

Continue to Calculate Performance Metrics for Daily Flows