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StateMod provides several methods to simulate structure demands. The selection of a demand approach is relatively simple for a system with surface water only. However for a system with both surface and ground water selecting an appropriate demand approach can be critical because diversions, wells and reservoir data often have different water use efficiencies. The following are noted:

  • Demand data may be provided at the supply point (includes inefficient water use) or as a consumptive requirement (includes no inefficient water use). When demands are provided as a consumptive requirement, the model adjusts the demand on-the-fly to include the inefficiencies associated with the water supply source (surface diversion or well) being simulated.
  • Demand data can be provided for diversions and wells separately or as a single value that may be served from surface or ground water supplies. The ability to separate or combine demands based on source allows the flexibility to perform both historic and calculated calibration.
  • Demands that can be served by both surface and ground water may be simulated using a Maximum Demand Approach. This approach allows a structure to divert surface water up to their decreed amount and limits ground water pumping to the consumptive requirement. This approach allows a user to divert surface water that may result in a relatively low water use efficiency but use ground water, as needed, at a relatively high efficiency.