Worksheet Grade 10 Engineering & Design

Cinderhill Wellfield Capacity: A Grade 10 Drawdown Worksheet

A grade 10 engineering worksheet on groundwater supply: students find well drawdown and specific capacity, combine well yields, and model yield as a function of drawdown.

Grade: Grade 10
Subject: Engineering & Design
Material: Worksheet
Time: 40 min
Prep: No prep
Materials: Calculator

Standards

HSN-Q.A.1 Common Core Math

Use units as a way to understand problems and to guide the solution of multi-step problems; choose and interpret units consistently in formulas; choose and interpret the scale and the origin in graphs and data displays.

How this material aligns: Items 1 through 4 and 6 through 8 carry water-level and yield units through drawdown in feet, specific capacity in gallons per minute per foot, and flow conversions from gallons per minute into million gallons per day.

All materials for HSN-Q.A.1 →

HSA-CED.A.2 Common Core Math

Create equations in two or more variables to represent relationships between quantities; graph equations on coordinate axes with labels and scales.

How this material aligns: Item 9 has students write a two-variable equation relating a well's yield to its drawdown using the specific capacity as the rate, then solve that equation for the drawdown a target yield would require, which item 10 reuses at a higher yield.

All materials for HSA-CED.A.2 →

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This material is in the public domain (CC0) and may be copied, edited, and shared freely, without attribution. Updated 2026-07-23.

Objectives

Students will calculate well drawdown and specific capacity from static and pumping water levels.
Students will combine well yields and write an equation relating a well's yield to its drawdown.

Vocabulary

Drawdown: Drawdown is how far the water level in a well drops when a pump pulls water out. The harder and longer you pump, the bigger the drawdown gets.

Also: static water level, specific capacity, yield, wellfield

Teacher overview

When a pump pulls water from a well, the water level in the well drops, and how far it drops for a given yield tells an engineer how productive the well is. This worksheet has students analyze the fictional Cinderhill wellfield, finding each well's drawdown and specific capacity, combining the wells' yields, and writing an equation that links a well's yield to its drawdown. A common misconception in this math is treating a deeper pumping level as a sign of a better well; a large drawdown for a small yield actually signals a less productive well, which is why engineers compare specific capacity, the yield per foot of drawdown, rather than the pumping level alone.

Cinderhill Wellfield Capacity: A Grade 10 Drawdown Worksheet — Grade 10 Engineering & Design

Name: ____________________________ Date: ______________

Student Worksheet

The Cinderhill wellfield (a fictional wellfield built for this worksheet) has two wells. Well 1 has a static water level of 45 feet and a pumping water level of 78 feet at a yield of 330 gpm. Well 2 has a static water level of 50 feet and a pumping water level of 95 feet at a yield of 360 gpm. Use drawdown = pumping water level − static water level, and specific capacity = yield ÷ drawdown.

Find Well 1's drawdown in feet.
Find Well 1's specific capacity in gpm per foot of drawdown, dividing its 330 gpm yield by the drawdown from problem 1.
Find Well 2's drawdown in feet.
Find Well 2's specific capacity in gpm per foot of drawdown, dividing its 360 gpm yield by the drawdown from problem 3.
Which well has the higher specific capacity, and what does that tell you about which well is more productive per foot of drawdown?
Find the combined yield of both wells in gpm.
Convert the combined yield from problem 6 to million gallons per day, using the conversion that 1 MGD equals 694 gpm.
Convert the combined yield from problem 6 to gallons per day, using 1,440 minutes per day.
Using Well 1's specific capacity of 10 gpm per foot, write an equation for the yield Y (in gpm) as a function of the drawdown d (in feet). Then use it to find the drawdown needed to pump 250 gpm from Well 1.
If Well 1 is pumped harder to 400 gpm and its specific capacity stays about 10 gpm per foot, estimate the new drawdown and the new pumping water level.
Explain why a long-term drop in the static water level across the wellfield, from over-pumping or drought, would lower how much water the wells can deliver.

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: 33 feet.
Drawdown = 78 − 45 = 33 feet.
Answer: 10 gpm per foot.
Specific capacity = 330 gpm ÷ 33 feet = 10 gpm per foot of drawdown.
Answer: 45 feet.
Drawdown = 95 − 50 = 45 feet.
Answer: 8 gpm per foot.
Specific capacity = 360 gpm ÷ 45 feet = 8 gpm per foot of drawdown.
Answer: Well 1.
Well 1's specific capacity of 10 gpm per foot is higher than Well 2's 8 gpm per foot, so Well 1 delivers more water for each foot the level drops, making it the more productive well per foot of drawdown.
Answer: 690 gpm.
Combined yield = 330 + 360 = 690 gpm.
Answer: about 0.99 MGD.
690 gpm ÷ 694 gpm/MGD = 0.994, which rounds to about 0.99 MGD.
Answer: 993,600 gallons per day.
690 gpm × 1,440 minutes/day = 993,600 gallons per day.
Answer: 25 feet.
The equation is Y = 10d. Solving 250 = 10d gives d = 250 ÷ 10 = 25 feet of drawdown.
Answer: 40 feet of drawdown.
Drawdown = 400 gpm ÷ 10 gpm per foot = 40 feet, so the new pumping water level is 45 + 40 = 85 feet.
Answer: Lower static level, less water.
Accept any answer explaining that pumping starts from a lower level, so the pump reaches its usable limit sooner and the same drawdown yields less water. Over-pumping or drought that lowers the static level shrinks the amount each well can safely deliver.

Differentiation

Support (below grade level)

Provide the two formulas (drawdown and specific capacity) on a reference card and complete Well 1's drawdown and specific capacity together, so students repeat the same two steps for Well 2 on their own.

Extension (above grade level)

Ask students to find the specific capacity a third fictional well would need to deliver 500 gpm at a drawdown of no more than 40 feet, and to explain what a low specific capacity would mean for the pump size and energy needed to reach that yield.

ELL supports

Provide a labeled well diagram showing the static water level, the pumping water level, and the drawdown between them, with yield and specific capacity defined beside it. Allow students to show problems 1 through 10 as numbered calculations and to answer problem 11 with a labeled sketch plus one sentence.