Regulation Recession
This category appears at the selection of any regulation discharge method in the Regulation Discharge category, so is related to the operating level balancing approach to flood control. It allows the user to limit by how much the regulation discharge recesses from one timestep to the next.
NoneThis default method for the category means no regulation recession is applied.
Regulation RecessionThis method limits the recession in regulation discharge to the amount specified in the Regulation Recession slot.
Slots Specific to This Method
Regulation Recession
Type: PeriodicSlot
Units: FLOW
Description: Schedule of the maximum amount by which the regulation discharge can be receded for a timestep, with different rows representing recessions at different time points in the schedule, and different columns representing recessions at different discharges. Legitimate recession values can be limited to only a certain range of discharges.
Information: This is a n x n periodic slot where the user specifies the period over which the schedule repeats (1 Day, 1 Year, and so on) and the table has the capability to generate a recession value for any date and discharge value from the schedule.
I/O: Required input
Links: Not linkable
Method Details
The Regulation Recession method steps through the timesteps in the forecast period and performs the following actions.
1. The current forecast timestep and the current regulation discharge value are looked up in the Regulation Recession table to see if a legitimate regulation recession value applies. If not, regulation discharge for the current timestep is unchanged and subsequent steps are skipped.
2. The previous forecast timestep’s regulation discharge is compared to the upper bound of the discharge range where recession applies (on the first forecast timestep, use the previous simulation timestep’s regulation discharge). If it was greater than the upper bound of the range, the current timestep’s regulation discharge is reset to this upper bound value.
3. If the previous forecast timestep’s regulation discharge was within the discharge range where recession applies, the regulation recession value is subtracted from the previous forecast timestep’s regulation discharge to get a recessed discharge.
4. If the current regulation discharge is more than the recessed discharge, it is unchanged.
5. If the current regulation discharge is less than the recessed discharge, the current regulation discharge is reset to the recessed discharge value.
Revised: 07/09/2023