Techniques and Methods 6–A36
ABSTRACTMany groundwater-management problems are concerned with the control of one or more variables that reflect the state of a groundwater-flow system or a coupled groundwater/surface-water system. These system state variables include the distribution of heads within an aquifer, streamflow rates within a hydraulically connected stream, and flow rates into or out of aquifer storage. This report documents the new State Variables Package for the Groundwater-Management Process of MODFLOW-2005 (GWM-2005). The new package provides a means to explicitly represent heads, streamflows, and changes in aquifer storage as state variables in a GWM-2005 simulation. The availability of these state variables makes it possible to include system state in the objective function and enhances existing capabilities for constructing constraint sets for a groundwater-management formulation. The new package can be used to address groundwater-management problems such as the determination of withdrawal strategies that meet water-supply demands while simultaneously maximizing heads or streamflows, or minimizing changes in aquifer storage. Four sample problems are provided to demonstrate use of the new package for typical groundwater-management applications. |
First posted March 7, 2011 For additional information contact: Part or all of this report is presented in Portable Document Format (PDF); the latest version of Adobe Reader or similar software is required to view it. Download the latest version of Adobe Reader, free of charge. |
Ahlfeld, D.P., Barlow, P.M., and Baker, K.M., 2011, Documentation for the State Variables Package for the Groundwater-Management Process of MODFLOW-2005 (GWM-2005): U.S. Geological Survey Techniques and Methods 6-A36, 45 p., at https://pubs.usgs.gov/tm/tm6-a36/.
Preface
Abstract
Introduction
Description of the State Variables Package
Definition of State Variables
State Variables in a GWM Formulation
Implementation of State Variables in GWM
Additional Extensions to GWM-2005 Necessary for the State Variables Package
Extended Definitions of External Variables
Extended Definitions of Objective-Function Types
Sample Problems
DEWATER-SV: Minimize Cost of Lowering Groundwater Levels
Groundwater-Management Problem
Selected Input and Output Files
MAXIMIN: Maximize the Minimum Hydraulic Head
Maximin and Minimax Formulations in Groundwater Management
Groundwater-Management Problem
Selected Input and Output Files
STREAMFLOW: Maximize Summer Streamflow
Groundwater-Management Problem
Selected Input and Output Files
STORAGE: Control Changes in Aquifer Storage
Groundwater-Management Problem
Selected Input and Output Files
Acknowledgments
References Cited
Appendix 1. Data-Input Instructions and Output Files
Appendix 2. Programmers' Guide to Implementation of State Variables in GWM-2005