Groundwater Contamination Hazcity Guide - Version 1

You have been asked to prepare a water table map for the area around Crossroads showing contour lines, flow directions, and the barium contaminant plume.

Your other job is to determine which residences might next be affected. This is to be done using well elevation data from a Surveyor, depth to water information from a hydrogeologist, and water chemistry reports from a water analysis lab.

This activity is solved through the following set of steps:

  1. Calculate the elevation of the water table at each well. You can do this by subtracting the depth to water table from the elevation of the top of the casing. The values should be written on the map, close to the wells where they were derived.
  2. You need to draw contour lines on the map to show the shape of the water table. Find which way the contour lines trend.
  3. According to the principles of groundwater flow, groundwater flow lines cross groundwater contour lines at right angles. Also, according to the principles of groundwater flow, the direction of groundwater flow is from areas of high water table elevations to areas of lower water table elevations. Find the flow directions in the Crossroads area.
  4. After knowing the flow direction in the area, the highest contaminated well, and the lowest well, find the source of the contamination compared to the location of the highest well. This tells you where the contaminant plume is originated, which direction its expands, and where (relative to the lowest well) it ends.
  5. Identify the wells that are in the most immediate danger of being contaminated.

Answer the following questions
NOTE: Use the scantron form provided in the classroom for your answers!