Objects
Inline Power Plants
The Inline Power Plant object’s calculation for the Flow Tables method was modified. Now the Power Plant Cap Fraction is applied to both the Turbine Release and the computed Power when the flow is above Max Turbine Release times the Power Plant Cap Fraction. It is not applied when the flow is less than Max Turbine Release times the Power Plant Cap Fraction. This change affects only Inline Power Plants using the Flow Tables method. See Flow Tables in Objects and Methods for more information.
Level Power and Storage Reservoirs
Unregulated Conditions
For some users, it is necessary to compute the flows in the basin that would have existed if reservoirs were not in place. To meet this need, the Pass Inflows method in the Disable Reservoir Processes category was created: The Pass Inflows method as described Pass Inflows in Objects and Methods does the following:
• Changes the Workspace Icon: When this method is selected, the icon on the workspace is modified to indicate the Reservoir is not calculating storage as shown to the right.
• Enables an alternative dispatch method: When this method is selected, only the Outflow Equals Sum of Inflows dispatch method is available. This dispatch method sets the Outflow = Sum of Inflows and does no further physical process modeling.
Using scripts (or manually), you can make a model run of your system with the reservoirs in place and executing all the operating policy (rules), then select these methods and re-run the model to get the unregulated conditions. Snapshots can be used to preserve the results between runs. This process and additional information on these methods can be found Modeling Unregulated Conditions in USACE‑SWD Modeling Techniques.
Water User
Methods were added to track the Soil Moisture on the Water User object and meet any remaining depletion requests with soil moisture. The new methods are:
• Irrigation Requests with Soil Moisture in the Diversion and Depletion Request category: This method computes the diversion and depletion request to meet irrigation demands and refill the soil moisture. See Irrigation Requests with Soil Moisture in Objects and Methods for more information.
• Proportional Shortage with Soil Moisture in the Return Flow category: This method computes the amount of water used from the diversion and from the soil moisture. A new soil moisture volume and return flow are computed. See Variable Efficiency with Soil Moisture in Objects and Methods for more information.
• Supplement Diversions including Soil Moisture in the Conjunctive Use category: This method computes the supplemental water required and then tries to meet that request. If there is surplus supplemental water, then it can be used to refill the soil moisture. See Supplement Diversion including Soil Moisture in Objects and Methods for more information.
Revised: 07/05/2022