Use of the Multi-Node Well (MNW) package when simulating solute transport with the MODFLOW ground-water transport process

Techniques and Methods 6-A15
Code and documentation for other water models are available at http://water.usgs.gov/software/ground_water.html .
By:  and 

Links

Abstract

This report describes modifications to a U.S. Geological Survey (USGS) three-dimensional solute-transport model (MODFLOW-GWT), which is incorporated into the USGS MODFLOW ground-water model as the Ground-Water Transport (GWT) Process. The modifications were made to create compatibility between the Multi-Node Well (MNW) Package for MODFLOW and the MODFLOW-GWT model. This compatibility improves the capability of MODFLOW-GWT to represent accurately solute transport in simulations that include multi-node wells because long-screen wells or long open boreholes that extend through multiple model layers can provide fast pathways for solutes to move from one location to another in a ground-water flow system. For nonpumping multi-node wells (used to simulate open boreholes or observation wells, for example), a simple routing and local mixing model was developed to calculate nodal concentrations within the borehole. A depth-averaged concentration is calculated for such nonpumping wells. For pumping multi-node wells (either withdrawal or injection) in which the flow between the well and the ground-water system is in the same direction at all nodes, the average concentration in the well is calculated as a flux-based mean assuming complete and instantaneous mixing in the wellbore of all inflows. For pumping multi-node wells (either withdrawal or injection) in which the flow between the well and the ground-water system is not unidirectional, the concentration distribution within the well is calculated using the same routing and local mixing model used for a nonpumping multi-node well, with the added assumption that the flux pumped in or out of the well is added or removed above the first well node.

Additional publication details

Publication type Report
Publication Subtype USGS Numbered Series
Title Use of the Multi-Node Well (MNW) package when simulating solute transport with the MODFLOW ground-water transport process
Series title Techniques and Methods
Series number 6-A15
DOI 10.3133/tm6A15
Edition Version 1.9
Year Published 2006
Language ENGLISH
Description 34 p.
Larger Work Type Report
Larger Work Subtype USGS Numbered Series
Larger Work Title Book 6: Modeling techniques, Section A. Ground-water
Additional Online Files (Y/N) Y