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Unformatted text preview: ed by the pump manufacturer. These data provide intermediate
values for a lookup table in which the end (limiting) values are derived from values specified earlier in dataset 2g. Appendix 1—Data Input Instructions for MultiNode Well (MNW2) Package 51 FOR EACH STRESS PERIOD:
3. Data:
ITMP ITMP is an integer value for reusing or reading multinode well data; it can change each stress period.
ITMP must be ≥ 0 for the first stress period of a simulation.
• if ITMP > 0, then ITMP is the total number of active multinode wells simulated during
the stress period, and only wells listed in dataset 4a will be active during the stress period.
Characteristics of each well are defined in datasets 2 and 4.
• if ITMP = 0, then no multinode wells are active for the stress period and the following
dataset is skipped.
• if ITMP < 0, then the same number of wells and well information will be reused from the
previous stress period and dataset 4 is skipped. IF ITMP > 0:
For each multinode well (that is, repeat dataset 4 ITMP times):
4a. Data: WELLID Qdes {CapMult} {Cprime} {xyz}
WELLID
must correspond with one of the names defined in dataset 2a. Including WELLID in this dataset
means it will be an active well during this stress period.
Qdes CapMult Cprime
[xyz] 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 pumpcapacity adjustments are not applied. is a flag and multiplier for implementing headcapacity relations during a given stress period.
Only specify if PUMPCAP > 0 for this well. If CapMult ≤ 0, then headcapacity relations
are ignored for this stress period. If CapMult = 1.0, then headcapacity relations defined
in datasets 2g and 2h are used. If CapMult equals any other positive value (for example,
0.6 or 1.1), then headcapacity relations are used but adjusted and shifted by multiplying the
discharge value indicated by the headcapacity curve by the value of CapMult. is the concentration in the injected fluid. Only specify if Qdes > 0 and GWT process is active. represents a list of up to five auxiliary variables for a multinode well that have been defined in
dataset 1. The auxiliary variables must be present in each repetition of dataset 4a if they are
defined in dataset 1. If Qlimit < 0:
4b. Data: Hlim QCUT {Qfrcmn Qfrcmx}
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.
QCUT is an integer flag that indicates how pumping limits Qfrcmn and Qfrcmx will be specified. If
pumping limits are to be specified as a rate (L3/T), then set QCUT > 0; if pumping limits are 52 Revised MultiNode Well (MNW2) Package for MODFLOW GroundWater Flow Model Qfrcmn Qfrcmx to be specified as a fraction of the specified pumping rate (Qdes), then set QCUT < 0. If there
is not a minimum pumping rate below which the pump becomes inactive, then set QCUT = 0. 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. 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. Note 10: Only specify dataset 4b if the value of Qlimit associated with the well defined by WELLID in dataset 4a is negative
(where Qlimit is defined in dataset 2b). Do not enter fractions as percentages. For example, if QCUT < 0, and the well
must exceed 80 percent of the original pumping rate to remain active, then enter a value of “0.8” for Qfrcmn. If QCUT > 0,
then the rates specified for Qfrcmn and Qfrcmx follow the sign convention for MODFLOW; that is, for discharging wells
the rate should be negative, and for recharging (injection) wells the rate should be positive. MultiNode Well Information (MNWI) Package
Data calculated for multinode wells can be recorded at every time increment using the MNWI Package. The
specific nature of the recorded and wr...
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 Winter '14

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