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Simulation Objects
The following enhancements to the RiverWare simulation objects are described briefly. The user is encouraged to consult the Simulation Objects Documentation in the online help for more detailed descriptions of the enhancements to the objects and their methods.
Control Point Object
Flood Control Methods
The control point methods related to flood control were reorganized by adding a highest level category called Flood Control. This category serves to split the phase balancing (COE-KC) and operating level balancing (COE-SW) procedures. If users have existing models using flood control and control points, they will need to make the appropriate selection in the flood control category (from the default of None to one of the two flood control methods) to get back the related flood control categories. If the control point is a key control point, then the appropriate method in the key control point balancing category will need to be re-selected. Also the appropriate method in the regulation recession category will need to be re-selected if it was active prior to this release.
Additonal Peaking Flow Slot
A new slot, Additional Peaking Flow, was added to the Regualtion Discharge methods. Input to the new slot is optional and existing models do not require any changes. Additonal Peaking Flow is the difference between the estimated peak flow through the control point (average over the timestep) and the instantaneous peak during the timestep. Additional Peaking Flow is used in the empty space calculation. Empty space is calculated as the regulation discharge minus the inflow, minus the local inflow, minus the additional peaking flow (if a value is input). Typically, the Additional Peaking Flow slot will contain zeros for most timesteps and peak values on certain timesteps with peaks.
Reservoir Objects
Changes to Plant Efficiency Curve Power Method
The Plant Efficiency Curve Power Method on the Power Reservoirs has been changed. The method now generates the Auto Best Turbine Q Table using the second to last point in the Plant Power Table for a given operating head (previously, the second point was used). If there are only two points in the table for a given operating head, the second point is both the best efficiency and max capacity point.
The Plant Efficiency Curve Power method was new in the 4.4 release and allows the user to input several efficiency points instead of just the two (the best and max) available with the Plant Power Calc method. The Plant Power Table (a 3-D table that relates Operating Head, Turbine Release, and Power) is used to automatically generate the max and best turbine Q tables (called Auto Best Turbine Q and Auto Max Turbine Q) for this method.
Changes to Peak Power Calc and Peak Base Power Calc
In the PeakPowerCalc and PeakBasePowerCalc methods, if the Plant Power Cap Fraction was set to zero the Turbine Release was not automatically set to zero. Instead water was allowed to pass through the turbines instead of the spillways. Now, in both methods, if the Plant Power Cap Fraction is zero the Turbine Release is set to zero and any outflow is being correctly sent through the spillways.
Changes to Physical Constraint Methods (affects HypSim)
The physical constraint functionality was enhanced to eliminate problems associated with the hypothetical simulation functions. While this problem fixes some rare hypothetical simulation bugs, it could produce differences in the values returned by hypothetical simulation (especially when the outflow is at max capacity). The new code should improve the accuracy of hypothetical simulation but the user should be aware of possible model differences because of this.
Slope Power Reservoir
A new method category called Slope Partition was added to the Slope Power reservoir object. The new category contains the Partition BW Elevation method. This method allows the user to divide the reservoir into longitudinal partitions and calculate the steady flow through each partition (intermFlowParams). The flow parameter at each partition is then used in a 3-D table interpolation to find the backwater (BW) elevation at each of the partitions. This method does not affect the mass balance calculations and does not sum for the total storage over all partitions.
Stream Gage
Fractional Flow Method
The Stream Gage has a new method category, Conditional Flow Calc, that contains the Fractional Flow user method. The default method in this category is None, so existing models do not require changes. The new user method, Fractional Flow, calculates and sets Gage Inflow based on a comparison between two conditions. If Condition One is less than Condition Two, then the Gage Inflow is set to Condition One multiplied by a user input seasonal Loss Factor plus a user specified Constant. If Condition One is not less than Condition Two, then Gage Inflow is set to a user specified Normal Flow. The following pseudo-code displays the logic of how the Gage Inflow slot is calculated:
IF (Condition One (e.g., Diversion) < Condition Two (e.g., Diversion Requested))
The Condition One, Condition Two, and Normal Flow slots can be user input, linked, or set by rules.
A new dispatch method solveGageInflowGivenConds sets Gage Inflow if the two dispatch slots Condition One and Condition Two are known. The gage object will dispatch using solveGageInflowGivenConds only if the user method Fractional Flow has been selected and neither Gage Inflow nor Gage Outflow are known. If the None method is selected, the Stream Gage does not dispatch. In that case, Gage Inflow and Gage Outflow are internally linked so values propagate immediately. This internal linking was the existing behavior on the Stream Gage.
Revised: 08/02/2021