In the reservoir flashboards and superboards unregulated spill methods, a check was added to see if the availability slot is input or set by a rule. Previously, the availability was just checked for inputs, not rules. Now, users can set the availability with a rule.

An error check was added to the Flattop Surcharge method to ensure that the non-zero portion of the Rating Curves is increasing.

In the Peak Power Equation with Off Peak Spill method on the power reservoirs, the following warning message was removed: “Pool Elevation too low to generate power.” This warning message was posted any time the reservoir was below the Minimum Power Elevation. The method behaves the same as previously: power and energy are still calculated to be zero; only the message has been removed.

Two new methods were added to reservoir objects in the new Calculate Incremental Hydrologic Inflows on Subbasin category: Compute Full Run Incremental Hydrologic Inflows and Compute Forecast Period Incremental Hydrologic Inflows methods. These methods are used to disaggregate cumulative hydrologic inflows. The first method disaggregates cumulative inflows to Incremental Hydrologic Inflows for the entire run. The second method forecasts and disaggregates cumulative inflows to incremental hydrologic inflows on each timestep throughout the forecast period.

On reservoir objects, the name of the slot “Deterministic Hydrologic Inflow” was changed to “Cumulative Hydrologic Inflow.” In addition, the forecast methods in the Generate Forecast Hydrology category that previously used the “Deterministic Hydrologic Inflow” slots now use the new “Deterministic Incremental Hydrologic Inflow.”

If you use one of the Generate Forecast Hydrology methods that use these slots, there are two options:

In addition, if any of these slots are referenced by DMIs, output manager devices, rules, or expression slots the models will need to be modified. See Generate Forecast Hydrology in Objects and Methods for information on the Generate Forecast Hydrology category for the storage reservoir.

A new category, Variable Routing Coefficients was added to the Control Point. Within this category, a new method, Compute Aggregate Coefficients allows the user to specify that this Control Point has an alternative set of routing coefficients that are to be used in the Flood Control calculation. See Control Point Variable Routing Coefficients category for more information.

This category has two methods that are used to hold the slots necessary for the calculation of Distributed Flow at an ungaged control point using the known flow at the Gage Control Point on the computational subbasin. In the WAM Precipitation Curve Number method, there are six slots: Distributed Flow, Drainage Area, Curve Number, Mean Precipitation, Upstream Gages, and Downstream Gage. These slots will be accessed by the computational subbasin when executing the computational subbasin’s WAM Precipitation Curve Number method. In the Drainage Area method, there are four slots: Distributed Flow, Drainage Area, Upstream Gages, and Downstream Gage. In both of these methods, the computational subbasin will use the user input Distributed Flow values in the Gage Control Point to calculate and set the Distributed Flow values at all other control points in the subbasin. The WAM Precipitation Curve Number method takes into account the drainage area, mean precipitation and NRCS Curve Number while the Drainage Area method uses only the drainage area in the calculation. For more information, see Local Inflow Spatial Disaggregation on Subbasin in Objects and Methods.

A new category, Gage Control Point, was added to the Control Point when the WAM Precipitation and Curve Number method is selected. Methods in this category are used to indicate which Control Points are the “gage” control points. There are two methods in this category: the default, no action None method and the Gage Control Point method. When selected, the Gage Control Point method indicates that the control point is considered a “gage” control point. When this method is selected, the Control Point changes from a blue color to an orange color. For more information, see Gage Control Point in Objects and Methods.

A new method category, Local Inflow Temporal Disaggregation on Subbasin, was added to the control point. The Local Inflow Temporal Disaggregation on Subbasin method category contains two new methods: None, and Specified Factors. The Specified Factors method contains one new slot: Temporally Disaggregated Flow. This slot holds the result of the temporal disaggregation as calculated from the computational subbasin. For more information, see Local Inflow Temporal Disaggregation on Subbasin in Objects and Methods.

Two new methods were added to control point objects in the new Calculate Incremental Local Inflows on Subbasin category: Compute Full Run Incremental Local Inflows and Compute Forecast Period Incremental Local Inflows methods. These methods are used to disaggregate cumulative local inflows. The first method computes incremental local inflows for the entire run. The second method computes forecasted incremental local inflows on each timestep for the forecast period. For more information, see Compute Incremental Local Inflows on Subbasin in Objects and Methods.

On Control Points, the name of the slot “Deterministic Local Inflow” was changed to “Cumulative Local Inflow.” In addition, the forecast methods in the Generate Forecast Inflows category that previously used the “Deterministic Local Inflow” slots now use the new “Deterministic Incremental Local Inflow.”

If you use one of the Generate Forecast Inflows methods that use these slots, there are two options:

In addition, if any of these slots are referenced by DMIs, output manager devices, rules, or expression slots the models will need to be modified. See Generate Forecast Inflows in Objects and Methods for details on the Generate Forecast Inflows category for the Control Point.

Functionality was added to allow the subbasin to use alternative routing coefficients in the Flood Control calculation. A new category called Control Point Variable Routing Coefficients was added to the computational subbasin. In this category are two methods, a default do-nothing No Method, and the new method Compute Aggregate Coefficients. This new Compute Aggregate Coefficients method is used to determine the set of routing coefficients to use for each Control Point in the subbasin. For each Control Point, the method aggregates routing coefficients using the intervening reach routing methods. This allows the Flood Control calculation to make use of variable routing coefficients during high flow events. This calculation is only performed during the Flood Control calculation and does not affect the routing in the simulation objects. For more information, see Control Point Variable Routing Coefficients in Objects and Methods.

It is now possible to have more than one downstream-most object in a subbasin used by the Flood Control predefined function.

A new method category, Local Inflow Spatial Disaggregation, was added to the computational subbasin. The category contains three methods: the default no-action method None, the WAM Precipitation Curve Number, and the Drainage Area method. The WAM Precipitation Curve Number method calculates the Distributed Flow at an ungaged control point using the known flow at the Gage Control Point as well as the NRCS curve number, mean precipitation, and drainage area of both the gaged and ungaged control points. The Drainage Area method calculates the Distributed Flow at an ungaged control point using known flow at the Gage Control Point using drainage area ratios only. For more information, see Local Inflow Spatial Disaggregation in Objects and Methods.

A new method category, Local Inflow Temporal Disaggregation, was added to the computational subbasin. The category contains two methods: the default no-action method None, and the Specified Factors method. The Temp Disagg Factors slot is required input for the Specified Factors method and holds a daily timeseries of the factors by which the monthly Distributed Flow values are multiplied to temporally disaggregate to daily. In practice, the data for the Temp Disagg Factors slot can be developed from historical daily data that is converted to a daily factor (percent per day of the monthly value). This slot is located on the computational subbasin (and not the control point) because the disaggregation factors apply to all control points in the subbasin. For more information, see Local Inflow Temporal Disaggregation in Objects and Methods.

A new method category, Calculate Incremental Local Inflows, was added to the computational subbasin. The category contains three methods: the default no-action method None, the Compute Full Run Incremental Local Inflows method, and the Compute Forecast Period Incremental Local Inflows method. The latter two methods calculate the incremental local inflows to all control points and reservoirs in the subbasin given the cumulative local inflows at each object without forecasting and with forecasting, respectively. The computational subbasin(s) must be set up by the user and must include all control points and reservoirs which contain the cumulative local inflow data as well as all the intervening reaches and confluences. Cumulative local inflow data can be either cumulative until a reservoir is reached in the river system or continue through one or more reservoirs. For more information, see Incremental Local Inflows in Objects and Methods.

A new category Reservoir Boundary for Incrementals is available if one of the Calculate Incremental Local Inflows is selected. The category contains three methods, the default Stop at Reservoirs, Continue Through Reservoirs, and Ignore Reservoirs. These methods are used to specify how cumulative local inflows are configured in the basin. For more information, see Reservoir Boundary for Incrementals in Objects and Methods.

On the Diversion object's solveMB_givenOutflow dispatch method, “Available for Diversion” was removed as a required known in the dispatch conditions. This dispatch method solves for the Diversion and Diversion Request given the Multi Outflow. Typically, the Multi Outflow is calculated by a rule using the ComputeReservoirDiversions predefined function. This function determines the reservoir diversion and limits diversions to be less than the available water in the reservoir. As a result, Available for Diversion is not a required known for this dispatch method. For more information, see Solve given Multi Outflow in Objects and Methods.

A new method Base Plus Fractional Loss was added to the GainLoss Calculation category on the reach. This method models loss in a reach as a base loss plus a loss fraction of the flow above that base. In addition, total loss is limited to a maximum value. For more information, see Base Plus Fractional Loss in Objects and Methods.

A new routing method, Variable Step Response, was added to the Reach. In this routing method, the user specifies a set of flow thresholds and a set of corresponding step response routing coefficients. When the reach dispatches, the routing method selects the appropriate routing coefficients based on the inflow to the reach. This method was added to support systems where large overbank floods lead to increased travel times. For more information, see Variable Step Response in Objects and Methods.

A new category called Fraction Return Flow Input was added to the Water User object. This category, dependent on the selection of the Fraction Return Flow method in the returnFlowCalculation category, specifies how the Fractional Return Flow slot is to be input. Within this category are three new methods: Input Fraction, Zero Fraction, and Periodic Fraction. The default method is the Input Fraction which duplicates the existing functionality. The Zero Fraction method sets a zero for Fraction Return Flow each timestep. The Periodic Fraction allows the user to input a periodic slot that is used to calculate the Fractional Return Flow. For more information, see Fraction Return Flow Input in Objects and Methods.