Worksheet Grade 9 Engineering & Design

Duskin Community Farm: Drip Irrigation Design Worksheet

A grade 9 worksheet where students size a drip system for a fictional community farm plot, finding flow, run time, and the water it saves over sprinklers.

Grade: Grade 9
Subject: Engineering & Design
Material: Worksheet
Time: 40 min
Prep: No prep
Materials: None

Standards

HSG-MG.A.2 Common Core Math

Apply concepts of density based on area and volume in modeling situations (e.g., persons per square mile, BTUs per cubic foot).

How this material aligns: Item 3 applies gallons per square foot to turn a target watering depth over the plot area into total gallons, the area-density modeling this standard names.

All materials for HSG-MG.A.2 →

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 2, 4, and 9 carry units through flow, run-time, and percent-saved calculations, the multi-step unit reasoning this standard requires.

All materials for HSN-Q.A.1 →

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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 the total flow and run time of a drip irrigation system.
Students will compare drip and sprinkler efficiency to find the water a drip system saves.

Vocabulary

Drip irrigation: Watering plants through tubes that release water slowly, drop by drop, right at the roots. Very little water is wasted along the way.

Also: emitter, application depth, efficiency

Teacher overview

Duskin Community Farm is a fictional garden plot that grows vegetables for a neighborhood. Its planners want a drip system that waters the roots slowly and wastes little. This worksheet has students size that system and compare it to a sprinkler. Drip irrigation drops water right at the plant, so less water blows away or evaporates.

Duskin Community Farm: Drip Irrigation Design Worksheet — Grade 9 Engineering & Design

Name: ____________________________ Date: ______________

Student Worksheet

Use these facts about the fictional Duskin Community Farm plot.

The plot is 6,000 square feet.
The system has 20 rows with 30 emitters in each row. Each emitter drips 0.5 gallons per hour (gph).
To apply water 1 inch deep over 1 square foot takes 0.623 gallons.
The goal is to apply water 0.5 inch deep each time the farm waters.
Drip irrigation is about 90 percent efficient. A sprinkler is about 65 percent efficient.

How many emitters does the whole system have? (Rows × emitters per row.)
What is the system's total flow, in gallons per hour? (Emitters × 0.5 gph.)
How many gallons reach the soil to apply 0.5 inch over the whole plot? (Area × depth × 0.623.)
How long must the system run to deliver that many gallons? (Gallons ÷ flow in gph.) Round to the nearest tenth of an hour. Ignore efficiency for now; item 7 returns to it.
If the farm waters 3 times a week, how many gallons does it apply to the soil in one week? (Item 3 answer × 3.)
In one sentence, explain why a slow drip wastes less water than a fast spray.
A drip system is 90 percent efficient. To get the item 3 gallons to the roots, how many gallons must it apply? (Item 3 gallons ÷ 0.90.) Round to the nearest whole gallon.
A sprinkler is only 65 percent efficient. To get the same item 3 gallons to the roots, how many gallons must it apply? (Item 3 gallons ÷ 0.65.) Round to the nearest whole gallon.
How many gallons does the drip system save over the sprinkler for one watering, and what percent of the sprinkler amount is that? (Subtract, then divide by the sprinkler gallons.) Round the percent to the nearest tenth.
In one or two sentences, name one design change that would save even more water, and explain why.

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: 600 emitters.
20 rows × 30 emitters = 600 emitters.
Answer: 300 gph.
600 emitters × 0.5 gph = 300 gallons per hour.
Answer: 1,869 gallons.
6,000 sq ft × 0.5 inch × 0.623 = 1,869 gallons.
Answer: 6.2 hours.
1,869 ÷ 300 = 6.23, which rounds to 6.2 hours.
Answer: 5,607 gallons.
1,869 × 3 = 5,607 gallons in one week.
Answer: A slow drip soaks into the soil near the roots, while a fast spray throws water into the air and onto bare ground, where more of it evaporates or runs off.
Answer: 2,077 gallons.
1,869 ÷ 0.90 = 2,076.7, which rounds to 2,077 gallons. At 300 gph the system must run 2,077 ÷ 300 = 6.9 hours, longer than the item 4 estimate.
Answer: 2,875 gallons.
1,869 ÷ 0.65 = 2,875.4, which rounds to 2,875 gallons.
Answer: 798 gallons.
2,875 − 2,077 = 798 gallons saved. As a percent of the sprinkler amount, 798 ÷ 2,875 × 100 = 27.75, which rounds to 27.8 percent.
Answer: Accept any reasonable change with a matching reason, such as watering early in the morning to cut evaporation, adding mulch to hold soil moisture, or using a moisture sensor so the system runs only when the soil is dry.

Differentiation

Support

Give students the plot area and the 0.623 factor already placed in item 3 as a set-up multiplication, so they carry out one calculation rather than building it. Provide a labeled sketch of a row of emitters to make the count in item 1 concrete.

Extension

Ask students to find the yearly water saved if the farm waters 3 times a week for 30 weeks, using their item 9 saving per watering. Then have them state one assumption their estimate depends on.

ELL supports

Pre-teach "emitter," "drip," and "efficiency" with a picture of a single emitter dripping at a plant's base next to a spraying sprinkler. Provide a sentence frame for item 6: "A slow drip wastes less because ___."