Pumping Rate Tab

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The Pumping Rate tab on the MNW2 pane is used to specify the pumping rates for the multi-node well as well as other variables that vary with time.

Starting time and Ending time are explained in the help for the MODFLOW Features tab.

Desired pumping rate (Qdes) is the actual (or maximum desired, if constraints are to be applied) volumetric pumping rate (negative for withdrawal or positive for injection) at the well (L3/T). Qdes should be set to 0 for nonpumping wells. If constraints are applied, then the calculated volumetric withdrawal or injection rate may be adjusted to range from 0 to Qdes and is not allowed to switch directions between withdrawal and injection conditions during any stress period. When PUMPCAP > 0, in the first stress period in which Qdes is specified with a negative value, Qdes represents the maximum operating discharge for the pump; in subsequent stress periods, any different negative values of Qdes are ignored, although values are subject to adjustment for CapMult. If Qdes ≥ 0.0, then pump-capacity adjustments are not applied.

Head capacity multiplier (CapMult) is a flag and multiplier for implementing head-capacity relations during a given stress period. Only specify if PUMPCAP > 0 for this well. If CapMult ≤ 0, then head-capacity relations are ignored for this stress period. If CapMult = 1.0, then head-capacity relations defined in datasets 2g and 2h are used. If CapMult equals any other positive value (for example, 0.6 or 1.1), then head-capacity relations are used but adjusted and shifted by multiplying the discharge value indicated by the head-capacity curve by the value of CapMult.

Limiting water level (Hlim) is the limiting water level (head) in the well, which is a minimum for discharging wells and a maximum for injection wells. For example, in a discharging well, when hWELL falls below hlim, the flow from the well is constrained.

Pumping limit method (QCUT) is an integer flag that indicates how pumping limits Qfrcmn and Qfrcmx will be specified. Pumping limits can be specified as a rate (L3/T), as a fraction of the specified pumping rate (Qdes). If there is not a minimum pumping rate below which the pump becomes inactive, then set QCUT = 0.

Deactivation pumping rate (Qfrcmn) is the minimum pumping rate or fraction of original pumping rate (a choice that depends on QCUT) that a well must exceed to remain active during a stress period. The absolute value of Qfrcmn must be less than the absolute value of Qfrcmx (defined next). Only specify if QCUT ≠ 0.

Reactivation pumping rate (Qfrcmx) is the minimum pumping rate or fraction of original pumping rate that must be exceeded to reactivate a well that had been shut off based on Qfrcmn during a stress period. The absolute value of Qfrcmx must be greater than the absolute value of Qfrcmn. Only specify if QCUT ≠ 0.