Last Pass Timesteps May Increase
This category appears only if the Operating Level Balancing method is selected in the Flood Control category.
Note: This method category and its methods exist for convenience of algorithm development, and they may not be available in the future.
When the Operating Level Balancing method runs the final pass of the flood control algorithm, it may subject each timestep’s proposed releases to the same constraints as prior passes (except the Key Control Point Max Release and Key Control Point Space Use never apply on the last pass), or it may add an additional constraint to timesteps after the first.
Note: This method exists for the purpose of approximating SUPER results.
Current Simulation Timestep Only This is the default method.
Limit increases in releases after the first timestep of the schedule on the last pass. Releases on timesteps after the first are subject to one more constraint on the final pass: that they do not exceed the larger of the following:
• The value proposed on the prior pass for the timestep
• The value proposed on this pass for the prior timestep minus the trim value (Maximum Release Variation slot)
This method allows some reservoirs to make larger releases than they might otherwise make, and reduces releases for some reservoirs on the current simulation timestep. Its effect is not predictable.
There are no slots specific to this method.
Method Details
If the Last Pass Timesteps May Increase selection is Current Simulation Timestep Only, this constraint is applied. After the first two of three passes, RA’s proposed release schedule is {50, 70, 90, 30, 10}. Its Maximum Release Variation (trim) is 10, and its Allowable Rising Release Change is 20. Now we run the final pass, and, having eliminated the constraints imposed by the key control point CPY, we could now release {80, 100, 100, 100, 90}. This constraint says that we will release {80, 70, 90, 80, 70}. The first timestep is unconstrained here; the second is constrained by both (or either, since they are the same) the value proposed on the prior pass (70) and the value proposed on this pass, prior timestep (80) minus the trim value (10). The third day is constrained by the prior schedule. The fourth day is constrained by 90-10=80, which is larger than 30, so it is the upper bound, and the last day is also constrained by the prior timestep minus trim.
Entire Forecast PeriodLet the last pass behave like all other passes, except the Key Control Point Max Release and Key Control Point Space Use never apply on the last pass.
There are no slots specific to this method.
Revised: 01/10/2022