Task 3: Reservoir Volume Reduction Modeling with Rule-Based Operation Method (Elevation-Storage-Area)

Software Version

HEC-HMS version 4.12 was used to develop this tutorial.

Project Files

Download the initial model files here - Reservoir Volume Reduction_Outflow Curve Routing_Initial.zip

Overview

This example illustrates a method for developing a reservoir volume reduction application with the rule-based reservoir operation method.  This example focuses on using an existing HEC-HMS model and making appropriate modifications for a long-term reservoir volume reduction simulation. The HEC-HMS model must be reviewed to understand assumptions made when the model was developed.  It is also important to look over the calibration results and assess whether the computed simulation does a good job replicating measured accumulated sediment volume.  You may need to make additional adjustments based on your assessment. In this example, you will summarize the model parameters in the existing HEC-HMS model and choose appropriate input parameters for the Kanopolis lake simulation.  

Overview

This example contains steps to develop a basic HEC-HMS reservoir volume reduction model from scratch using existing field data. You will summarize the model parameters from the given field data set and choose appropriate input parameters for the reservoir sedimentation simulation. Data used in the development of this model can be found in the Reservoir_Data.dss file in the HEC-HMS project's "data" folder. 

The following figure shows the starting point for the example. Notice the basin model is configured to include a source element for measured inflows into Kanopolis, along with a downstream control point on the Smoky Hill River at Mentor, Kansas. A separate source element is included for inflows downstream of the lake. The model's rule based options are configured to release water from the reservoir according to requirements at the Mentor gauge. 

Review the Model

1. A initial HEC-HMS model of Kanopolis Lake has been prepared for you.  Refer to the following HEC-HMS tutorials and guides listed below for more information on creating a rule-based model in HEC-HMS.  
   1. Creating a Simple Model
   2. Rule Based Option for an HEC-HMS Reservoir Element
   3. GIS Tutorials and Guides
2. Launch HEC-HMS and open the project by selecting File | Open | Browse.  Navigate over to the project and select the HEC-HMS project named Kanopolis_Rules.hms. Select the Basin Models folder.  The Basin Model, Kanopolis_Rules, was prepared as a case study to demonstrate how the rule-based operation can be used for sediment analysis. A second basin model that uses an outflow time-series approach for reservoir routing is included for comparison. For this timeseries, outflow from the reservoir was estimated by combining measured reservoir releases and evaporation, with some adjustments to ensure the water budget balanced over longer periods of time. 
3. Review the rule based options set in Kanopolis Reservoir Element. Four zones were used for the reservoir corresponding to different zones of the flood pool. During high flow events, releases from the reservoir are limited by the flow rate at the Mentor gauge on the Smoky Hill River. In low flow periods, releases must ensure that flow is at least 20 cfs at the Mentor gauge. 
   
   
4. Select the Brune Sediment Trap option in the Reservoir tab.
5. Enter the following parameters for the Brune Trapping efficiency method in the Sediment tab. The Brune parameters were estimated from  
   1. Annual Inflow Volume: 158,294 ac-ft (estimated from inflow data)
   2. Capacity Elevation: 1463 (multipurpose pool elevation)
   3. Constant A: 97 (selected by comparing Brune estimates to measured trapping efficiency)
   4. Constant B: 6.42 (selected by comparing Brune estimates to measured trapping efficiency)
   5. Reservoir Capacity Method: Yes
   6. Deposition Shape Elongated Taper
      
6. Run both simulations by selecting Run: Kanopolis - Rule Curve and Kanopolis - Timeseries from the simulation toolbar (shown below) and then clicking the compute button .
   
7. Plot results for the reservoir element for both simulations.  

   
   

   Question 1: How does the simulated pool elevations compare to the measured data? What could be causing some of the differences observed for the rule-based simulation?

   
   
   Answer

   Nash-Sutcliffe is 0.987 for the timeseries approach and 0.9 for the rule-based approach. A possible source for the higher error in the rule-based simulation could be that the lake's water managers do not release the maximum allowable amount. 

   
   

8. Compare the ELEVATION-Storage tables between initial surveyed data and final results for both simulations.
   1. Go to this example's HEC-HMS project folder using File Explorer.
   2. Open the output DSS file (Kanopolis_Rules.dss and Kanopolis_Timeseries) using DSSVue.
   3. Select the three ELEVATION-STORAGE curves as shown below (these should be the first and last ELEVATION-AREA records). The D-part pathname shows the date the elevation-area information was updated (based on the amount of sediment into the reservoir). 
      1) //Kanopolis/ELEVATION-STORAGE/31Oct2007:2400//RUN:Kanopolis - Rule Curve/
      2) //Kanopolis/ELEVATION-STORAGE/21Oct2017:1200//RUN:Kanopolis - Rule Curve/
      3) //Kanopolis/ELEVATION-STORAGE/21Oct2017:1200//RUN:Kanopolis - Timeseries/
      
      
   4. Tabulate the results by clicking the tabulate button .
      

Question 2: What is the total deposition for both simulations?

Question 3: What would be the advantage of using a rule-based approach rather than the timeseries approach?

Project Files

Download the final model files here - Reservoir_Volume Reduction_Outflow Curve Routing_Final.zip