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Objects and Methods : Groundwater Storage : User Methods : Solution Type
Solution Type
* Single Computed Outflow
This is the default method in the Solution Type category. It allows the groundwater object to solve.
Slots Specific to This Method
 Inflow
Type: MultiSlot
Units: FLOW
Description: flow rate at entrance of the object
Information: May be set as input by the user, or linked to the return flow of one or more other objects.
I/O: Optional; either input or set by propagation across a link
 Outflow
Type: SeriesSlot
Units: FLOW
Description: flow rate at exit of the object
Information:  
I/O: Output only
 Inflow from Groundwater
Type: MultiSlot
Units: FLOW
Description: flow into the groundwater storage object from nearby groundwater storage objects
Information: The subslots of this multislot contain the individual inflow values. A subslot is created when you link this slot to an origin object.
I/O: Output only
* Head Based Groundwater Grid
The Head Based Groundwater Grid method is used to instantiate the appropriate slots, user method categories, and dispatch methods for solution with connections to other objects (groundwater, reaches, and so on). There are no calculations specifically associated with this user method. Rather, the method is used to specify the solution type performed by the groundwater object.
Note:  RiverWare assumes a consistent datum throughout all related objects’ elevation and stages slots.
Slots Specific to This Method
 Inflow from Surface Water
Type: Multi Slot
Units: flow
Description: Inflow(s) to the groundwater object from the surface water system
Information: A positive value is an inflow to the groundwater object. Since this slot is a Multi Slot, it can include inflows from multiple surface water sources. If this slot is not linked, it is set to zero at the beginning of the run. It is a required known for dispatching.
I/O: Input or linked
 Elevation
Type: Series Slot
Units: length
Description: The water table elevation of the groundwater object. Datum should be consistent throughout all related objects’ elevation and stages slots.
Information: This value is computed as a function of change in storage, Area, and Specific Yield. The convergence on the Elevation slot is automatically set to None and cannot be changed. Resetting this slot is controlled by the convergence criteria of the Storage slot. That is, if Storage is reset, then Elevation is reset. If Storage is within convergence and not reset, then Elevation is also not reset.
I/O: Output; the initial elevation value must be input
 Elevation Previous
Type: Series Slot
Units: length
Description: The previous water table elevation
Information: This slot is used to control dispatching between connected groundwater objects. It will have the same value as the Elevation slot at the previous timestep. When the Elevation is computed during dispatching, the same value will be set on the Elevation Previous slot at the NEXT timestep to trigger the dispatching of connected groundwater objects at the next timestep.
The convergence on the this slot is automatically set to None and cannot be changed. Resetting this slot is controlled by the convergence criteria of the Storage slot. That is, if Storage is reset, then Elevation Previous is reset (at the next timestep). If Storage is within convergence and not reset, then this slot is also not reset.
I/O: Output only
 Specific Yield
Type: Scalar Slot
Units: none
Description: The ratio of the volume of water added or removed directly from the saturated groundwater to the resulting change in the volume of groundwater below the water table
Information: The specific yield is used to compute water table elevation as a function of Area and change in storage
I/O: Required input
 Area
Type: Scalar Slot
Units: Area
Description: The horizontal area of the groundwater. The surface area of the water table.
Information: Used to compute groundwater elevation and evapotranspiration.
I/O: Input or computed; see Compute Conductance.
 Specified Inflow
Type: Series Slot with Periodic Input
Units: Flow
Description: Inflows to the groundwater object typically from other groundwater objects that are not modeled. This slot provides a place to specify any inflows that aren’t classified as other inflows.
Information: This value can be positive (into the object) or negative (out of the object). Specified Inflows that are negative can cause the storage to become negative.
I/O: Input as a periodic or series data. Specify a single value if you have a constant value. If no value is specified, it is assumed the value is zero, but that is not shown on the slot.
* Head Based Boundary Condition
The Head Based Boundary Condition method is used to add the appropriate slots, user method categories, and dispatch methods for solution of a groundwater network linked to a reservoir. This method triggers the Solve given Elevation Previous dispatch method; see Solve given Elevation Previous.
An object with this method selected should be linked to a single Reservoir object with the Linked Seepage method selected (see Linked Seepage). It should also be linked to one or more Groundwater objects with the Head Based Groundwater Grid method selected for the Solution Type. There are no calculations specifically associated with this user method. Rather, the method is used to specify the solution type performed by the Groundwater object.
Note:  RiverWare assumes a consistent datum throughout all related objects’ elevation and stages slots.
There is no Storage on a Groundwater object with this method selected. It is added only as a means to convey Seepage water from the linked Reservoir into the linked Groundwater object. The Elevation on this object will be the same as the Pool Elevation on the Reservoir.
When this new method is selected, the following categories are available:
The Groundwater Evaporation, Groundwater Evapotranspiration, Groundwater Pumping, and Groundwater Water Quality, methods will not be available.
Slots Specific to This Method
 Elevation Previous
Type: Series
Units: Length
Description: Represents the previous timestep Pool Elevation of the linked Reservoir; datum should be consistent throughout all related objects’ elevation and stages slots
Information: This slot is used to control dispatching between connected groundwater objects. It will have the same value as the Elevation slot at the previous timestep. The value will come from the linked Reservoir dispatching and propagating the value across the link.
I/O: Output only
 Elevation
Type: Series
Units: Length
Description: Represents the Pool Elevation of the linked Reservoir; datum should be consistent throughout all related objects’ elevation and stages slots
Information:  
I/O: Output only
 Inflow from Surface Water
Type: Multi Slot
Units: Flow
Description: Inflow(s) to the groundwater object from the surface water system, typically from a linked Reservoir
Information: A positive value is an inflow to the groundwater object.
I/O: Output only
Method Details  
The typical linking to connect a groundwater network to a Reservoir object is shown in Figure 15.5. The object Under would have the Head Based Boundary Condition method selected for the Solution Type and is used to convey the Seepage from the Reservoir to the laterally linked Groundwater objects. The laterally linked Groundwater objects would have the Head Based Groundwater Grid method selected for the Solution Type. There may be 1-4 laterally linked Groundwater objects. The appropriate Elevation Previous and Flow Factor slots should be linked between the Under Groundwater object and the laterally linked Groundwater objects. The linking with the Reservoir object is illustrated in Figure 15.5.
Figure 15.5   
Revised: 07/09/2023