The Target Operation category is used to enable algorithms which calculate different lumped mass balance algorithms required by Target Operations (see TARGET flag). None of the methods exist as separate functions, meaning that the target operation algorithms themselves must be used in conjunction with the other mass balance algorithms. It is important to note that either the Simple Target or Lagged Target method must be selected if a target operation is set on the Reservoir.

This is the default method in the Target Operation category. It performs no calculations. It may only be selected if a Target Operation is not performed on the object.

There are no slots specific to this method.

The Simple Target method distributes the required Inflow or Outflow evenly among all available timesteps. The total flow is divided among all the non-input timesteps included within the Target Operation to meet the Target. For most cases with a target operation, this is the desired behavior.

Evaporation and precipitation are not included in the lumped mass balance of the target operation.

There are no slots specific to this method.

The Lagged Target method should be used when there are lag times in the upstream reaches. When Inflows are known, this method solves for the same solution as the Simple Target method. When Outflows are known, this method distributes the required Inflow so a steady Outflow occurs from an upstream, non-integer timestep lagged, reservoir. To distribute Inflows, the Total Lag of Upstream Reaches and Outflow from Upstream Reservoir are used to calculate the required Inflows to the current Reservoir. These required Inflows must meet the Target and result in steady Outflow from the upstream Reservoir. The solution yields a perturbed Inflow at the first undetermined timestep of the Target Operation, followed by steady Inflows for the remainder of the undetermined target times. This solution removes the numerical instability which would be produced in the Outflow of the upstream reservoir using the Simple Target method.