Groundwater modeling using GIS technology

Jessie Ackerman

Introduction

• Groundwater is an important freshwater resource

• Groundwater is held in aquifers

• Studying groundwater is difficult because it’s underground

• Groundwater modeling was developed to understand what’s going on

• Modeling has developed as new technologies have developed

Purpose

• Understand how GIS is used in groundwater modeling

• Analyze current material on topic

• Decide if GIS is useful in modeling groundwater

Basics of groundwater

• Darcy’s Law

Q = - Ksat*A*dh/dx • Understanding of flow• Modeling developed

first from an understanding of Darcy’s Law

Groundwater modeling

• Field data including hydrological inputs, hydraulic parameters and initial and boundary conditions are gathered

• Data input into modeling software

• Models can be 1-D, 2-D, semi 3-D and 3-D

1-D model

2-D model

Semi 3-D model

Integrating GIS in models

• GIS is a true 3-D model• Hydrologists looked to

GIS to demonstrate erosion, sediment transport, and chemical transport simulations

• Needed a program that could handle lots of data

• Need to connect globally

Basics of GIS

• A computer system designed to process information with a spatial content dimension

• Composed of a geographical database and a toolkit

Modeling with GIS

Example using GIS technology

• Searching for suitable area to tap aquifer near a landfill or other area of possible contamination

• Landfill data and aquifer data input into GIS model

• Program runs all possible situations

Work being done now using GIS technology

• Recharge and discharge rates of aquifers

• Used to make important decisions about water management

• Illinois State Water Survey and University of Illinois

Buena Vista Ground Water Basin, Wisconsin

Analysis of resources

• All but one source spoke well of using GIS within groundwater modeling

• One source just tells hydrologists to be wary in using only GIS software to model groundwater

Conclusions

• Gained an understanding of how GIS is used in groundwater modeling

• GIS is very useful in creating 3-D models that incorporate lots of data

• The best way to know if any advanced model is right is to go through it the long way first than to take shortcuts