Claire Chadwick; Lauren Maurizio; Robin Humphreys; and Vijay Vulava
Groundwater Models
In this section, we will use groundwater models to visualize groundwater flow below the ground using groundwater models. Because groundwater cannot be seen from above the ground, we often use groundwater models to visualize the movement of groundwater through different layers beneath the ground surface and study how contaminant plumes may develop when contaminants leak into the ground.
Watch the video demonstration of the Groundwater Model by a CofC instructor to help you answer the questions below (turn on close captioning if needed):
Exercise 5 – Groundwater Model
Use the resource below to answer the following questions:
- The above video has the information needed
- Identify three types of sediment that were shown in the model.
- Which of the following sediment layer(s) can act as an aquifer?
- Which of the following sediment layer(s) will act as an aquitard?
- Explain your previous answers.
- Where was the water table clearly visible?
- What is an unconfined aquifer?
- What is a confined aquifer?
- How does the water table (level) in adjacent wells respond when a well is pumped (on the model, withdrawing water with a syringe):
- What is this water table response in the adjacent wells called?
- What happened to the water table in the adjacent wells when the pumping stopped?
Hydrologists (geologists who study groundwater) want to know how fast water moves through an aquifer. They inject dye into a well C (on the left) and test water samples daily from well B (on the far right) to look for traces of the dye. Wells C and B are 1.6 km apart and the dye was detected in Well C 42 days later. The location of the wells is indicated on the groundwater model in the video above. Determine the groundwater flow rate in m/hr.
[latexpage] \[
\text{Flow Rate} = \frac{\text{Distance}}{\text{Time}}
\]
- Determine the distance between the wells in m (1 km = 1000 m):
- Determine the travel time for the dye in hr (1 day = 24 hr):
- Determine the groundwater flow rate in m/hr:
A truck carrying hazardous chemicals overturned near Well C. Using the relative locations of Wells, A, B, and C on the groundwater model in the video, answer the following questions:
- Groundwater from Well A will be affected by the chemical spill. T/F
- Explain your previous answer.
- Groundwater from Well B will be affected by the chemical spill. T/F
- Explain your previous answer.
- If the chemical contaminants travel at the same rate as the chemical dye, how long will it be before the chemicals reach Well B.
- The aquifer tapped by Well D will be affected by this spill. T/F
- Explain your previous answer.
