The WEL: Well package pane is on the MODFLOW Features tab of the Object Properties dialog box.
The data that can be specified for the Well package are the Starting time, Ending time, and Pumping rate. The Pumping rate is the volumetric recharge rate. A positive value indicates recharge and a negative value indicates discharge (pumping).
Starting time and Ending time are explained in the help for the MODFLOW Features tab.
If parameters are used with an object, a multiplier must be defined for each parameter for the Pumping rate. MODFLOW will multiply the multiplier by the parameter value (specified in the MODFLOW Packages and Programs dialog box) to determine the pumping rate to apply.
Well Multiplier is only used if it has been activated in the WEL: Well Package. If Well Multiplier is specified, the pumping rate is multiplied by the Well Multiplier value.
In MODFLOW, the Pumping Rate or Maximum Capacity is described as having units of L3/T.
However, sometimes it is convenient to define a well using a line or polygon object.
For Polyline Objects, the length of the object in the cell can be determined with the function ObjectSectionIntersectLength.
One way to to set the pumping rate would be with a formula that includes ObjectSectionIntersectLength and either a value or a user defined Global Variables for the pumping rate per unit length. For example, the user could define a Global Variables named "RatePerLength" and then set the pumping rate of the well using the following formula.
RatePerLength * ObjectSectionIntersectLength
A similar formula appropriate for Polygon Objects would be
RatePerArea * ObjectIntersectArea
where "RatePerArea" is a global variable.
However, if Pumping Rate Interpretation is set to Calculated, as it is by default, ObjectSectionIntersectLength and ObjectIntersectArea should not be included in the formulas because they will be incorporated automatically for polyline and polygon objects. Thus, if Pumping Rate Interpretation is set to Calculated for a Polyline Object, the pumping rate should be treated as if its units were L2/T.
Pumping Rate Interpretation has no effect for point objects. For point objects, the formulas will be applied without any modification regardless of Pumping Rate Interpretation.
if Pumping Rate Interpretation is set to Calculated for a Polygon Object, the pumping rate should be treated as if as if its units were L/T.
If Pumping Rate Interpretation is set to Direct, the formulas will be applied without any modification.
If Pumping Rate Interpretation is set to Total per layer the formulas will be modified by multiplying the conductance by ObjectSectionIntersectLength / ObjectLength or ObjectIntersectArea / ObjectArea.
Setting the Pumping Rate Interpretation to Calculated or Total per layer allows ModelMuse to calculate an appropriate pumping rate for a cell based on the length or area of intersection between the object and cell. However, if you calibrate your model and then change the grid size, the pumping rate assigned by ModelMuse may no longer be appropriate and you may have to recalibrate your model.
If an object defines a well in the Well package in MODFLOW and the object has more than one section, each section will be used to define a separate set of wells. If two or more sections of the same object occur in the same cell, a single well will be defined for that cell with the total pumping rate being the sum of the pumping rates for each section considered separately.
