Learning Module: Groundwater Flow
Module Goal
- Provide an overview of the principles of hydrogeology.
- Complete groundwater contouring exercises.
Overview
When Judge Skinner divided the trial into three separate portions, it became crucial that the parties be able to explain how contaminants traveled from the Grace and Beatrice sites to Wells G & H. The experts employed by both the defense and plaintiffs struggled with familiarizing the jurors the principles of groundwater flow and how their explanations validated their positions.
Basics of ground-water hydrology
The principles of groundwater flow are based on Darcy's experiments using flow-through cylinders containing porous media (sand). One of the difficulties with understanding ground-water characteristics is related to the inability to directly observed groundwater flow. Groundwater scientist (hydrogeologists) use measurements from wells drilled into the saturated zones along with models (analytical, numerical, scale representations, etc.) to analyze and predict groundwater flow and behavior. The US Geological Survey publication, Water-Supply Paper 2220, a PDF document, is a comprehensive document describing the principles of understanding and evaluating groundwater flow.
An important part of evaluating groundwater is determining groundwater flow directions. determining flow is accomplished by measuring water levels in Wells, correlating the water levels to a common datum (such as sea level) and contouring the water level elevations. when the contours have been drawn, the slope of the contours service reflects the flow direction with higher elevations flowing to those areas were lower elevations occur.
Activities to help broaden the understanding of groundwater
There are probably several opportunities within the community where groundwater operations can be observed. If nearby communities are served by groundwater supplies, arranging to have students visit the wellfield and see the pumping and distribution operations will provide them with a greater appreciation of the complexity of groundwater as a resource. Industrial sites and gasoline service stations are another potential opportunity to observe groundwater dynamics. There is a possibility at these locations that remedial actions of groundwater have been, or are being implemented. Depending on the nature of the situation, property owners may be amenable to providing a tour of the groundwater collection or treatment operations. any of these opportunities would give students "hands-on" experience regarding some of the issues and professional opportunities related to groundwater science.