Worksheet Grade 6 Science

Which Way Is the Groundwater Moving Under Denholm Yard?

A grade 6 science worksheet using three fictional monitoring wells to find water-table elevations, the flow direction of a diesel spill, and where to drill the next well.

Grade: Grade 6
Subject: Science
Material: Worksheet
Time: 40 min
Prep: No prep
Materials: None

Standards

MS-ESS2-4 NGSS

Develop a model to describe the cycling of water through Earth's systems driven by energy from the sun and the force of gravity.

How this material aligns: Items 6, 12, and 14 have students describe the groundwater pathway of the water cycle, following the slope of the water table under gravity rather than the slope of the ground, and the closing sand-tank activity has them build a physical model of that pathway.

All materials for MS-ESS2-4 →

6.RP.A.3 Common Core Math

Use ratio and rate reasoning to solve real-world and mathematical problems, e.g., by reasoning about tables of equivalent ratios, tape diagrams, double number line diagrams, or equations, including finding a percent of a quantity and converting measurement units.

How this material aligns: Item 8 asks for a gradient as feet of drop per foot of distance, and items 9 and 10 use a rate of feet per day to find travel time and convert days into years.

All materials for 6.RP.A.3 →

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This material is in the public domain (CC0) and may be copied, edited, and shared freely, without attribution. Updated 2026-09-04.

Objectives

Students will calculate water-table elevation from ground elevation and depth to water.
Students will determine which way groundwater moves across a site from three well readings.
Students will recommend a location for a new monitoring well and justify it.

Vocabulary

Water table: The water table is the underground level below which the ground is completely soaked with water. Dig a hole deeper than the water table and it will start filling with water.
Monitoring well: A monitoring well is a well drilled specifically to check on groundwater, not to supply drinking water. Scientists use monitoring wells to measure how high the water table is and to test for pollution before it can spread.

Also: elevation, gradient, plume

Teacher overview

This worksheet puts students in the position of a field crew trying to work out which way a fuel spill will travel underground at a fictional salvage yard. The misconception it is built to expose is the belief that groundwater runs in underground rivers that follow the slope of the land you can see. Groundwater follows the slope of the water table, which is a surface of its own and does not have to match the hills above it. The three wells in this scenario are arranged so that the ground surface dips and then rises while the water table falls steadily in one direction, so a student who reads the ground elevations alone will send the crew the wrong way. Item 14 asks students to name that mistake directly.

Which Way Is the Groundwater Moving Under Denholm Yard? — Grade 6 Science

Name: ____________________________ Date: ______________

Student Worksheet

Denholm Yard is an old salvage yard in the fictional town of Wexbourne. A buried tank there leaked diesel fuel. Every number below was written for this worksheet.

The crew drilled three monitoring wells, called A, B, and C. The wells sit in a straight line. Well B is between the other two. Well A and Well B are 500 feet apart. Well B and Well C are 250 feet apart, so Well A and Well C are 750 feet apart.

At each well the crew recorded two numbers. Ground elevation is how high the ground surface is above sea level. Depth to water is how far down the crew had to lower a tape before it touched water. The water-table elevation is the ground elevation minus the depth to water.

Well	Ground elevation (feet)	Depth to water (feet)
A	412	22
B	402	19
C	409	31

Two more facts about the site. The leaking tank sat 50 feet from Well A, on the side toward Well B. The Wexbourne school well is 900 feet from the tank, in the direction the water table slopes. Groundwater at this site moves about 0.5 foot per day.

Find the water-table elevation at Well A.
Find the water-table elevation at Well B.
Find the water-table elevation at Well C.
Which of the three wells has the highest water table?
The ground surface at Well C is 7 feet higher than the ground surface at Well B. Is the water table under Well C higher than the water table under Well B? Answer yes or no.
Groundwater moves from a higher water table toward a lower one. Does the water under the tank move toward Well A or toward Well C?
How many feet does the water table drop between Well A and Well C?
The gradient is the drop divided by the distance. Wells A and C are 750 feet apart. Find the gradient in feet of drop per foot of distance.
Groundwater here moves about 0.5 foot per day. The school well is 900 feet from the tank. How many days would water take to travel that far?
Change your answer to item 9 into years. Use 365 days in a year and round to the nearest tenth.
The tank sat 50 feet from Well A, on the side toward Well B. Which well would show diesel first, Well B or Well C?
The town wants one more well that would find the diesel before it reaches the school well. Where should the crew drill it?
A neighbor's well sits 300 feet from the tank, on the far side of Well A. That well tested clean. Does that prove the spill is small? Answer yes or no.
Explain in two sentences why a crew that looked only at the ground elevations would guess the wrong direction at this site.

From Water for Schools (waterforschools.org). This material is in the public domain (CC0) and may be copied, edited, and shared freely.

Answer Key

Answer: 390 feet.
Ground elevation minus depth to water gives 412 minus 22, which is 390 feet above sea level.
Answer: 383 feet.
402 minus 19 equals 383 feet above sea level.
Answer: 378 feet.
409 minus 31 equals 378 feet above sea level.
Answer: Well A.
Well A's water table is 390 feet, compared with 383 feet at Well B and 378 feet at Well C.
Answer: No.
The water table under Well C sits at 378 feet, which is 5 feet lower than the 383 feet under Well B, even though C's ground surface is higher. Accept any answer of no that names the two water-table elevations.
Answer: Toward Well C.
Water moves from the higher water table toward the lower one, so it moves from A toward B and on toward C.
Answer: 12 feet.
390 feet at Well A minus 378 feet at Well C equals a drop of 12 feet.
Answer: 0.016 feet per foot.
12 feet of drop divided by 750 feet of distance equals 0.016. Accept 0.016 written as a decimal or as the fraction 12 over 750.
Answer: 1,800 days.
900 feet divided by 0.5 foot per day equals 1,800 days.
Answer: 4.9 years.
1,800 days divided by 365 days per year equals 4.93, which rounds to 4.9 years.
Answer: Well B.
The tank sits between Well A and Well B, and the water moves from A toward C, so it reaches Well B before it reaches Well C.
Answer: Between Well C and the school well.
The diesel travels down the water-table slope, past Well C, and on toward the school. A well placed anywhere along that line between the tank and the school gives warning first. Accept any answer that places the new well between the spill and the school well.
Answer: No.
That neighbor's well sits on the uphill side of the water table, so the diesel moves away from it. A clean sample there tells you nothing about the size of the spill.
Answer: The ground surface falls from Well A to Well B and then rises again at Well C.
A crew reading only ground elevations would think the water turns around somewhere between B and C. The water-table elevations fall steadily from 390 to 383 to 378 feet, so the water keeps moving one direction the whole way. Accept any answer that contrasts the two surfaces.

Differentiation

Support

Give these students the water-table elevation column already filled in, so items 1 through 3 become a check rather than a calculation, and let them start at item 4. Provide a number line marked from 375 to 395 feet where they can plot the three water-table elevations and see the slope. Allow calculators for items 8 through 10, and accept one sentence for item 14.

Extension

Ask students to redraw the site with Well C's depth to water changed to 20 feet, recompute all three water-table elevations, and state what the flow direction becomes and what that would mean for the school well. A second option is to write a short memo to the Wexbourne town board recommending how often the new well should be sampled and why.

ELL supports

Pre-teach "water table," "elevation," "monitoring well," and "gradient" with a labeled cross section showing the ground surface, three wells, and the sloping water table drawn as a line. Provide the sentence frames "The water table at Well ___ is ___ feet" and "The water moves toward Well ___ because ___." Allow items 12 through 14 to be answered with a labeled drawing plus one sentence.

Extensions

Have students build a shallow model in a clear plastic bin using sand, a low dam of clay, and water added at one end, then push straws into the sand as wells and measure the water level in each. They can compare the slope of the sand surface with the slope of the water in the straws and check whether the two agree. Food coloring added at the high end shows the path the water actually takes.