Flood Control Release
Flood control releases on reservoirs cause dependent slots to be available for use by the predefined flood control rule function.
NoneThe default. No dependent slots.
Operating Level BalancingChoose this method when you wish to use rules to perform Operating Level Balancing flood control on a computational subbasin, of which this reservoir is a member; see Operating Level Balancing for details. See Flood Control in USACE‑SWD Modeling Techniques for details on using this method for USACE-SWD.
Slots Specific to This Method
Forecast Period
Type: Scalar
Units: No units
Description: Number of timesteps in the forecast period.
Information: Number of timesteps over which storages are forecasted and surcharge releases are calculated; includes current timestep. Values must be identical for all reservoirs in the computational subbasin on which flood control is performed. May be propagated from the subbasin.
I/O: Required input
Links: Not linkable
Balance Period
Type: Scalar
Units: No units
Description: Number of timesteps in the balance period.
Information: Number of timesteps into the future at which the flood control inspects the storage of the reservoir to determine the goal for flood control releases. The goal is to release all the water in the flood pool at this future timestep (the current timestep is 1). Values must be identical for all reservoirs in the computational subbasin on which flood control is performed. May be propagated from the subbasin.
I/O: Required input
Links: Not linkable
Target Balance Level
Type: Series
Units: No units
Description: Balance level assigned to this subject reservoir by a controlling key control point, during execution of the control point’s Operating Level Balancing method in the Key Control Point Balancing category.
Information: This slot is written as a result of the FloodControl predefined function; see FloodControl in RiverWare Policy Language (RPL).
I/O: Output only - set by a rule.
Links: Not linkable
Max Flood Control Release
Type: Series
Units: Flow
Description: Upper bound on flood control release, used by Operating Level Balancing flood control algorithm, and computed by Operating Level Balancing key control point balancing method on key control points. The flood control algorithm applies this upper bound on intermediate passes of the algorithm, but not on the last pass.
Information: This slot is invisible but can be viewed in the Special Results details on the Model Run Analysis tool; see Model Run Analysis—Special Results Details Dialog in USACE‑SWD Modeling Techniques.
I/O: Rule output.
Links: Not linkable.
Flood Control Release
Type: Series
Units: Flow
Description: The release made from the reservoir as a result of the application of a flood control rule.
Information: The value for this slot is computed by the flood control predefined rules function. The slot’s value is meant to be assigned by the rule.
I/O: Rule output.
Links: Not linkable
Flood Control Minimum Release
Type: Series Slot
Units: Flow
Description: This slot holds the user specified (via a rule) minimum flood control release. This slot is used by the Operating Level Balancing algorithm as a minimum release, but is not included in the Flood Control Release slot’s value. See Flood Control Minimum Release in USACE‑SWD Modeling Techniques for details on the intended use of this slot.
Information: This value should be set (along with Outflow) prior to calling the flood control method so that water is allowed to route downstream.
I/O: Typically set by a rule
Links: Not linkable
Proposed Flood Control Release
Type: Series
Units: FLOW
Description: The running value of the flood control release calculated by the Flood Control Release method on the Computation Subbasin.
Information: This slot is used to hold proposed flood control release during the flood control calculations. This slot is invisible but can be viewed in the Special Results details on the Model Run Analysis tool; see Model Run Analysis—Special Results Details Dialog in USACE‑SWD Modeling Techniques.
I/O: Output
Links: Not linkable
Surcharge Release
Type: Series
Units: Flow
Description: The release made from the reservoir as a result of the application of surcharge release rule.
Information: The values in this slot are used by the Operating Level Balancing flood control method invoked by the predefined rules function.
I/O: Rule output.
Links: Not linkable
Top of Flood Pool
Type: Scalar
Units: No units
Description: Operating level (as defined in Operating Level Table) corresponding to the top of the flood pool.
Information: Values must be identical for all reservoirs in the computational subbasin on which flood control is performed. May be propagated from the subbasin.
I/O: Required input
Links: Not linkable
Top of Conservation Pool
Type: Scalar
Units: No units
Description: Operating level (as defined in Operating Level Table) corresponding to the top of the conservation pool.
Information: Must be lower than the Top of Flood Pool. Values must be identical for all reservoirs in the computational subbasin on which flood control is performed. May be propagated from the subbasin.
I/O: Required input
Links: Not linkable
Operating Level Table
Type: Periodic
Units: Time vs Length at Operating Levels
Description: Describes the seasonal variation of elevation (storage) in a reservoir at each of the user-designated operating levels.
Information: Number of rows defined by the number of date points (user input); number of columns defined by the number of operating levels (user input). Each column represents the time-varying elevations for a particular Operating Level. The integer value of the Operating Level is in the first row (header) of each column. An elevation value is input for each operating level on each date point. All entered values have units of length. User can select whether to interpolate between values in time, or to have constant values until the next timestep. See Conditional Operating Levels for a method to modify which operating level table is used within a run.
I/O: Required input
Links: Not linkable
Allowable Rising Release Change
Type: Scalar
Units: Flow Per Time
Description: The maximum acceleration of the flood control releases, used by the rules-based Operating Level Balancing flood control. Value must be greater than 0.
Information: The Operating Level Balancing flood control algorithm attempts not to exceed this increase in outflow from one timestep to the next when computing flood control releases. Surcharge releases may cause this change to be exceeded. Value is converted to the internal units appropriate to the timestep size of the run, thus, is independent of the run’s timestep size.
I/O: Required input
Links: Not linkable
Allowable Falling Release Change
Type: Scalar
Units: Flow Per Time
Description: The maximum deceleration of the flood control releases, used by the rules-based Operating Level Balancing flood control. Value must be greater than 0.
Information: The Operating Level Balancing flood control algorithm attempts not to exceed this reduction in outflow from one timestep to the next when computing flood control releases. Channel space limitations may cause this change to be exceeded. Value is converted to the internal units appropriate to the timestep size of the run, thus, is independent of the run’s timestep size.
I/O: Required input
Links: Not linkable
Maximum Release Variation
Type: Scalar
Units: Flow Per Time
Description: A deceleration of the flood control releases assumed to occur during calculation of channel space in the rules-based Operating Level Balancing flood control. Value must be greater than 0.
Information: The Operating Level Balancing flood control algorithm uses this value as a tuning parameter. Large values mean that flood releases may be larger today and thus, zero tomorrow due to routing lags, whereas small values may mean that less-than-ideal releases can be made today; in either case, poor choices can cause oscillations in the reservoirs’ releases. Value is converted to the internal units appropriate to the timestep size of the run, thus, is independent of the run’s timestep size.
I/O: Required input
Links: Not linkable
Through Release
Type: Series
Units: Flow
Description: Water released from upstream reservoirs that flows through this reservoir. This reservoir is a downstream tandem.
Information: This slot is invisible but can be viewed in the Special Results details on the Model Run Analysis tool; see Model Run Analysis—Special Results Details Dialog in USACE‑SWD Modeling Techniques.
I/O: Output only
Links: Not linkable
Tandem Storage
Type: Series
Units: Flow
Description: All or part of a proposed release may be stored in downstream tandem reservoirs if the downstream reservoir is not Surcharging (Surcharge Release equals zero or is not valid) at the current controller timestep. This slot tracks the water stored in this reservoir.
Information: This slot is invisible but can be viewed in the Special Results details on the Model Run Analysis tool; see Model Run Analysis—Special Results Details Dialog in USACE‑SWD Modeling Techniques.
I/O: Output only
Links: Not linkable
Lost Tandem Storage
Type: Agg Series
Units: Flow
Description: This slot tracks the lost storage (as a flow) that occurs because tandem releases are not routed from the upstream to the downstream reservoir. It is really an error term. The first column is total of the other columns. Colum2 is for the current timestep releases. Column 2 is for timestep 1 through the balance period releases. Column 3 is for releases from the balance period through forecast period. For example the code decides to release 100cfs that can be stored in the downstream tandem. If you don't route it, 100 gets stored on the current timestep. But if you had routed it, some fraction would not have made it there on day 1 (1st column). If you instead propose a hydrograph of flows that don't get routed, then you can compute the col 2 and col 3 values.
Information: This slot is invisible but can be viewed in the Special Results details on the Model Run Analysis tool; see Model Run Analysis—Special Results Details Dialog in USACE‑SWD Modeling Techniques.
I/O: Output only
Downstream Control Point Share
Type: Agg Series
Units: decimal
Description: The slot has a series slot for each downstream key control point. The value in the slot shows the share as presented on the downstream Control Point’s Share slot. Essentially, this slot contains a copy of the downstream Control Point’s Share information.
Information: This slot is invisible but can be viewed in the reservoir’s Special Results details on the Model Run Analysis tool; see Model Run Analysis—Special Results Details Dialog in USACE‑SWD Modeling Techniques.
I/O: Output only
Links: Not linkable
Phase BalancingChoose this method when you wish to use rules to perform Phase Balancing flood control on a computational subbasin of which this reservoir is a member. See Phase Balancing discussion in the Computational Object for a complete discussion of the Phase Balancing algorithm.
Slots Specific to This Method
Forecast period
Type: Scalar
Units: No units
Description: Number of timesteps in the forecast period.
Information: Minimum value of 1. This value should be the same as the Forecast Period on other objects in the subbasin; the value can optionally be propagated from the subbasin.
I/O: Required input
Links: Not linkable
Surcharge Release
Type: Series
Units: Flow
Description: release required by operating policy when the reservoir elevation is in the surcharge pool.
Information: set by surcharge release method for all timesteps in forecast period when Surcharge Release flag is set on this slot by end user or by a rule
I/O: Output
Links: Not linkable
Top of Flood Pool
Type: Scalar
Units: No units
Description: Operating level (as defined in Operating Level Table) corresponding to the top of flood pool
Information: KC COE has used 4 in the past, but can be any number
I/O: Required input
Links: Not linkable
Top of Conservation Pool
Type: Scalar
Units: None
Description: The operating level pool number of the top of conservation pool level.
Information: This value is also termed the Target Operating Pool Level, since this is the preferred, or Target level for all reservoirs. This level is also the bottom of the flood pool level.
I/O: Input
Links: Not linkable
Operating Levels Table
Type: Periodic
Units: TIME vs Length at Operating levels
Description: Table describing the seasonal variation of elevation (storage) in a reservoir at each of the user-designated operating levels.
Information: Number of rows defined by the number of date points (user input); number of columns defined by the number of operating levels (user input). Each column represents the time-varying elevations for a particular Operating Level. The integer value of the Operating Level is in the first row (header) of each column. An elevation value is input for each operating level on each date point. All entered values have units of length. User can select whether to interpolate between values in time, or to have constant values until the next timestep. See Reach Evaporation for a method to modify which operating level table is used within a run.
I/O: Required input
Links: Not linkable
Operating Level
Units: Series
Units: No units
Description: Operating level of the reservoir at each timestep, based on the ending Storage.
Information: Determined from interpolation of the Operating Levels periodic plus the delta from the Operating Levels Aberration Agg Series Slot; an exact value is determined, not limited to an integer or values entered in the Operating Level Table.
I/O: Output
Links: Not linkable
Phase Tolerance
Type: Scalar
Units: No units
Description: The tolerance value that must be exceed for the reservoir to change phase.
Information: The reservoir phase is determined from the operating level. The operating level must exceed a phase boundary by the Phase Tolerance before the lake will change phase. This slot can be used to smooth oscillations along phase boundaries.
I/O: Input (0.0 default)
Links: Not linkable
Lake Character
Type: Series
Units: No units
Description: Weighting factor for allocating available downstream channel space.
Information: Used by control point or flood control algorithm to balance reservoirs in calculating flood releases
I/O: Output
Links: Not linkable
Lake Character Coefficient
Type: Scalar
Units: No UNITS
Description: Coefficient multiplied by the occupied volume of the flood pool to determine the Lake Character.
Information: Used for every timestep, unless Variable Lake Character Coefficient has been input (not a NaN) for some timestep(s).
I/O: Input
Links: Not linkable
Variable Lake Character Coefficient
Type: Series
Units: NO units
Description: Time-varying Lake Character Coefficient
Information: Replaces Lake Character Coefficient Scalar when input for some timestep(s).
I/O: Optional Input
Links: Not linkable
Flood Control Release
Type: Series
Units: FLOW
Description: Value of the flood control release calculated by the Flood Control Release method and set by the rule that calls that method.
Information: During the flood control calculations at each timestep, this value is calculated for the entire forecast period; at the next timestep, the forecast values are overwritten by the new values. At the end of the run, this slot contains the flood control release for all the timesteps. During dispatching, this value is added to the surcharge release and possibly other values to get the total outflow for the timestep.
I/O: Output
Links: Not linkable
Proposed Flood Control Release
Type: Series
Units: FLOW
Description: The running value of the flood control release calculated by the Flood Control Release method on the Computation Subbasin.
Information: This slot is used to hold proposed flood control release during the flood control calculations. This slot is invisible but can be viewed in the Special Results details on the Model Run Analysis tool; see Model Run Analysis—Special Results Details Dialog in USACE‑SWD Modeling Techniques.
I/O: Output
Links: Not linkable
Recalc Release
Type: Series
Units: FLOW
Description: The temporary running value of the reservoir’s current constrained release.
Information: This slot is used to hold the last constrained release of the reservoir. This value is kept in case the computational subbasin has the opportunity to recalculate the reservoir’s release (that is, one of this reservoir’s siblings cannot use all of its allocation allowing this flood control release of this reservoir to be increased). This slot is invisible but can be viewed in the Special Results details on the Model Run Analysis tool; see Model Run Analysis—Special Results Details Dialog in USACE‑SWD Modeling Techniques.
I/O: Output
Links: Not linkable
Known Release
Type: Series
Units: FLOW
Description: The temporary running value of the reservoir’s known or solved for releases.
Information: This slot is used for bookkeeping, holding the values of known or solved for releases in the forecast period during the flood control release algorithm. This slot is invisible but can be viewed in the Special Results details on the Model Run Analysis tool; see Model Run Analysis—Special Results Details Dialog in USACE‑SWD Modeling Techniques.
I/O: Output
Links: Not linkable
Phase
Type: Series
Units: No units
Description: A temporary record of the lake’s phase.
Information: This slot is used for bookkeeping, holding the values of the lake phase. This slot is invisible but can be viewed in the Special Results details on the Model Run Analysis tool; see Model Run Analysis—Special Results Details Dialog in USACE‑SWD Modeling Techniques.
I/O: Output
Links: Not linkable
Minimum Release
Type: Periodic
Units: FLOW
Description: The minimum release the reservoir is required to make. A seasonal value.
Information: Number of rows defined by the number of date points (user input) and one column. The column represents the time-varying minimum release for the reservoir.elevations for a particular Operating Level. An flow value is input for each date point. User can select whether to interpolate between values in time, or to have constant values until the next timestep.
I/O: Required input
Links: Not linkable
Tandem Operating Levels Table
Type: Periodic
Units: TIME vs Length at Operating levels
Description: Table describing the seasonal variation of elevation (storage) in a tandem reservoir at each of the user-designated operating levels.
Information: Number of rows defined by the number of date points (user input); number of columns defined by the number of operating levels (user input). Each column represents the time-varying elevations for a particular Operating Level. The integer value of the Operating Level is in the first row (header) of each column. An elevation value is input for each operating level on each date point. All entered values have units of length. User can select whether to interpolate between values in time, or to have constant values until the next timestep.
I/O: Required input
Links: Not linkable
Tandem Operating Level Aberrations
Type: Agg Series Slot
Units: No units
Description: Aberration of the operating levels of the tandem reservoir from the periodic specification at each timestep
Information: The slot contains an aberration series for each operating level. The aberration is used to adjust the tandem operating levels when constructing the tandem balancing curve.
I/O: Input
Links: Not linkable
Objective Release Pattern Table
Type: Table
Units: No units
Description: Table describing the objective releases percentages used to evacuate the flood control storage (including forecasted inflows) over the period of the table from the first unconstrained release.
Information: The nth number in the table represents the percentage of the flood control storage (include forecasted inflows) that should be released for the nth day from the first unconstrained release from this reservoir.
I/O: Required input
Links: Not linkable
Maximum Objective Release
Type: Series
Units: FLOW
Description: The temporary running values of the reservoir’s current objective releases. This slot is invisible but can be viewed in the Special Results details on the Model Run Analysis tool; see Model Run Analysis—Special Results Details Dialog in USACE‑SWD Modeling Techniques.
I/O: Output
Links: Not linkable
Objective Pattern Threshold
Type: Table
Units: NONE
Description: Percentage of allowable volume change in objective release pattern
Information: This is a Scalar representing the percentage of volume changed. If the change volume of flood control storage in a reservoir (including forecasted inflows) is within the threshold of the objective release pattern, then the pattern can be maintained and does not need to be recomputed. If the change exceeds the threshold then the pattern must be recomputed. The table has two columns. The first column lists outflows. The second column list the corresponding permissible decrease in outflow.
I/O: Required input
Links: Not linkable
Permissible Outflow Increase Constraints Table
Type: Table
Units: FLOW, FLOW
Description: Table describing the allowable outflow increase given a current outflow.
Information: The table has two columns. The first column lists outflows. The second column list the corresponding permissible increase in outflow.
I/O: Required input
Links: Not linkable
Permissible Outflow Decrease Constraints Table
Type: Table
Units: FLOW, FLOW
Description: Table describing the allowable outflow decrease given a current outflow.
Information: The table has two columns. The first column lists outflows. The second column list the corresponding permissible decrease in outflow.
I/O: Required input
Links: Not linkable
Cubic Bank StorageThe Cubic Bank Storage method calculates the Change in Bank Storage from an empirical equation given by the U.S. Bureau of Reclamation. This method was specifically developed for work on the Pecos. The empirical relations used in this method were derived from a study at the Reservoir. This method calculates a net overall loss rate. Bank Storage is not calculated in this method.
Slots Specific to This Method
Change in Bank Storage
Type: Series
Units: VOLUME
Description: Change in volume of water stored in reservoir banks
Information: Calculated by the cubic equation above.
I/O: Output only
Links: Not linkable
Cubic Bank Storage Falling
Type: Table
Units: NOUNITS vs. NOUNITS
Description: Constants for equation when reservoir level is falling
Information: The first coefficient (column zero) is the linear term (a) and the second coefficient is the cubic term (b).
I/O: Required input
Links: Not linkable
Cubic Bank Storage Rising
Type: Table
Units: NO UNITS vs. NO UNITS
Description: Constants for equation when reservoir level is rising
Information: The first coefficient (column zero) is the linear term (a) and the second coefficient is the cubic term (b).
I/O: Required input
Links: Not linkable
Method Details
Change in Bank Storage can be calculated in two ways, both of which based on the following equation:
where:
– a = the first coefficient in either the Cubic Bank Storage Falling slot or the Cubic Bank Storage Rising slot
– b = the second coefficient in either the Cubic Bank Storage Falling slot or the Cubic Bank Storage Rising slot
– Change in Bank Storage is in cfs
– Pool Elevation is in feet
Different sets of empirical coefficients are used to calculate the Change in Bank Storage depending on the direction of Pool Elevation movement. If the Pool Elevation is rising, the coefficients in the Cubic Bank Storage Rising slot are used. On the other hand, if the Pool Elevation is falling, the coefficients in the Cubic Bank Storage Falling slot are used.
Revised: 07/05/2022