GROUNDWATER FLOW MODELS AS A WATER RESOURCE MANAGEMENT TOOL

In many regions facing much tighter groundwater supplies than the Northeastern US and Eastern Canada groundwater flow models are routinely developed to help water managers, regulators and municipalities better understand the demands placed on groundwater resources. Some water-poor states in the southern US have even implemented permit and annual reporting requirements for withdrawals, which allows them to continually update the models. While this is an extreme approach that may not be appropriate for every region, it does illustrate the power of groundwater flow models to help balance competing demands for water resources.

Groundwater flow models are used to understand the following:

1. The water budget for a groundwater basin.

2. The interaction of groundwater and surface water using data on all water bodies and their behavior, including seasonal water gains and losses.

3. Natural resources' dependency on water levels.

4. The impact of withdrawals on other water users.

5. The nature and amounts of recharge to an aquifer.

Together, understanding these and other aspects of the model allow the modeler to create a detailed picture of how groundwater moves within a watershed, and how it interacts with natural resources, water bodies, and human users who rely on it. Once established, the model can be used to understand the effect of a change in conditions, such as diversion of flows or changes in precipitation.

This presentation will discuss the data required to develop a groundwater flow model, best practices for keeping the model up to date, and lessons from water-stressed regions that can be applied in the Northeast US and Eastern Canada.