Representation of Multiaquifer Well Effects in Three‐Dimensional Ground‐Water Flow Simulation

Abstract

The presence of multiaquifer or multilayer wells changes the nature of the equations which must be solved in a three‐dimensional ground‐water flow simulation and, in effect, alters the stencil of computation. A method has been devised which takes this change into consideration by allowing simulation of the hydraulic effects of a multiaquifer well on the aquifer system. It also allows for calculation of the water level and individual aquifer discharges in such a well. The method is valid for the case of a single well located at the center of a square node block. Where more than one well per node is involved, the effects of the stencil alteration still must be considered, although difficulties arise in estimating and justifying the parameters to be utilized.

Fracture Control of Ground Water Flow and Water Chemistry in a Rock Aquitard

“…All but one of the simulated water table head values and all the flux values fell within the target confidence intervals for both transient and steady‐state runs and were used in combination with the measured vertical head distribution in the field to assess model calibration. Monitoring well open intervals correspond to multiple model layers, so transmissivity‐weighted arithmetic mean head calculations (Sokol 1963; Bennett et al 1982) were needed for calibration purposes. These mean simulated hydraulic head values were compared to composite field hydraulic head values measured in open intervals spanning more than one model layer thickness.…”

“…Monitoring well open intervals correspond to multiple model layers, so transmissivity-weighted arithmetic mean head calculations (Sokol 1963;Bennett et al 1982) were needed for calibration purposes. These mean simulated hydraulic head values were compared to composite field hydraulic head values measured in open intervals spanning more than one model layer thickness.…”

Representing Pump‐Capacity Relations in Groundwater Simulation Models

“…Details about the MNW2 numerical scheme are described by Bennett et al (1982), Halford and Hanson (2002), Neville and Tonkin (2004), and Konikow et al (2009). If the pump‐capacity option is activated, at the beginning of each iteration cycle MNW2 updates the net discharge from the well on the basis of the most recent value of the water level in the well and the user‐defined pump‐capacity curve.…”

An evaluation of the bedrock aquifer system in northeastern Wisconsin

“…Much of the available historical potentiometric-head data for aquifers 1 and 2 are from wells open to both of these aquifers. To allow for comparisons between observed and computed heads in the aquifer system, the model program was modified by the northern Midwest RASA group to include a multiaquifer function (Bennett, Kontis, and Larson, 1982) to compute the composite heads for aquifers 1 and 2. The modification allows the model to compute the composite head for each node specified, based on the transmissivity, pumpage, and computed head of each aquifer at the end of the pumping period.…”