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Career spotlight Grade 7 Careers & CTE

The Water Master Who Divides the Tillingham River

A grade 7 spotlight on an irrigation district water master, following a delivery day on the fictional Tillingham River with ratio, percent, and acre-foot questions.

Objectives

  1. Students will describe how a water master measures and divides an irrigation supply.
  2. Students will explain the training routes that lead into irrigation district work.
  3. Students will use ratio and percent reasoning to divide and reduce a river diversion.

Vocabulary

Diversion
Taking water out of a river or stream and sending it somewhere else, such as into a canal or pipeline, to be used by farms or cities.
Headgate
The gate at the entrance of an irrigation canal or ditch that opens and closes to control how much water flows toward the fields.
Acre-foot
The amount of water it takes to cover one acre of land, about the size of a football field, one foot deep. Western states use acre-feet to measure large amounts of water.
Priority date
The date a water right was first established. In dry years the oldest dates get their water first, and newer users may get none at all.

Also: water master

Teacher overview

An irrigation district moves river water through canals to farms, and someone has to decide how much each farm receives on each day. That person is often called the water master. This profile follows one water master through a delivery day at the fictional Salterby Irrigation District, which draws from the Tillingham River. Students often picture irrigation as a farmer simply opening a valve, so the profile shows that deliveries are measured, ordered in advance, and limited by rules written long before anyone farming today was born.

The Water Master Who Divides the Tillingham River — Grade 7 Careers & CTE
Name: ____________________________ Date: ______________

Career Profile

A delivery day. Ana Bediako drives the canal road at first light. Growers place their water orders two days ahead, and her tablet lists every order for the day. At each headgate she reads a staff gauge, which is a marked plate that shows the depth of water in the canal. Depth tells her flow, because the district measured each structure years ago and built a table for it. She raises or lowers the gate until the flow matches the order, then records the reading.

Not every order can be filled. Water rights in many western states carry a priority date, and the oldest right is served first when the river runs low. Ana keeps that order in mind on every call. She also watches for trouble along the ditch. Weeds slow the flow, a muskrat hole can drain a bank, and a gate left open sends water where nobody ordered it. Twice this week she has driven back at night to shut a gate.

Late in the day she totals deliveries in acre-feet. One acre-foot equals 325,851 gallons, and it is the unit the district uses on every account. Growers are billed against the total, and the district reports its diversions to the state.

Routes into the work. There is no single path. Many water masters start as ditch riders after high school and learn the canal system on the job. Some take a two-year degree in irrigation technology or water management at a community college. Others come in with a four-year degree in agricultural or civil engineering and move from design work into operations. Districts commonly ask for a driver's license, comfort with hand tools, and a willingness to work early and late during the season. Several states now offer certificates in canal operations.

Pay and outlook. The Bureau of Labor Statistics does not report pay for irrigation district water masters as a separate job, so this profile does not give a figure for the role. The agency does publish an outlook for water and wastewater treatment plant operators, and it projects about 10,000 openings each year, on average, from 2025 to 2035, for operators specifically, not for the water sector as a whole. Districts across the West describe similar hiring pressure as long-serving staff retire. Agriculture accounts for roughly 70 percent of global freshwater withdrawals, so the work of dividing irrigation water is a large part of how fresh water is used.

Student Handout

Suppose the Salterby Irrigation District takes its supply from the Tillingham River. Each question below gives you the numbers you need.

  1. Name two tasks Ana does at a headgate.
  2. In your own words, explain what a priority date decides when the river runs low.
  3. Three farms hold shares in the ratio 5 to 3 to 2. The district may divert 60 cubic feet per second from the river. How many cubic feet per second go to the farm holding 5 shares?
  4. In a dry summer the district cut every delivery by 35 percent. The farm in question 3 had been receiving 30 cubic feet per second. What is its new delivery?
  5. One acre-foot equals 325,851 gallons. A grower orders 12 acre-feet. How many gallons is that?
  6. Ana checks 6 miles of canal road in 40 minutes. At that same rate, how many minutes would 21 miles take?
  7. Agriculture accounts for roughly 70 percent of global freshwater withdrawals. Explain why one water master's daily decisions matter to people who do not farm.
  8. Name one way a choice made in an upstream district can change daily life in a town downstream.

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

Answer Key
  1. Answer: Any two of these tasks. Ana reads the staff gauge, raises or lowers the gate to match the order, records the reading, checks the ditch for weeds or holes, or shuts a gate that was left open.
  2. Answer: It decides who is served first. The oldest right gets its water before newer rights when there is not enough river to fill every order.
  3. Answer: 30 cubic feet per second. The shares total 5 plus 3 plus 2, which is 10. One share is 60 divided by 10, or 6, so 5 shares is 5 times 6.
  4. Answer: 19.5 cubic feet per second. A cut of 35 percent leaves 65 percent, and 30 times 0.65 is 19.5. Students who subtract 35 from 30 have used the percent as a plain number.
  5. Answer: 3,910,212 gallons. Multiply 325,851 by 12. Ten acre-feet is 3,258,510 gallons and two more is 651,702 gallons, and those add to 3,910,212.
  6. Answer: 140 minutes. There are 21 divided by 6, or 3.5, groups of 6 miles, and 3.5 times 40 is 140.
  7. Answer: Accept any reasoned response. Sample response: farms use most of the fresh water that people withdraw, so decisions about irrigation change how much river is left for towns, fish, and power plants that share the same water.
  8. Answer: Accept any reasoned response. Sample response: if an upstream district diverts more water in a dry month, the town downstream may have a lower river at its intake and may have to ask people to use less.

Differentiation

Support

Give students a simple canal diagram showing the river, the main canal, and three farm headgates before they read. For question 3, provide the total number of shares so students begin at the step where they find the value of one share. Allow question 5 to be answered with a calculator and checked by estimating with 300,000 gallons per acre-foot.

Extension

Ask students to write the two-sentence notice Ana would post at a headgate on the first day of a delivery cut. The notice must state the size of the cut, name who is affected, and explain the reason in language a grower can act on. Students should use only the information given in this profile.

ELL supports

Pre-teach "headgate," "diversion," and "acre-foot" with a labeled drawing and a physical comparison for the acre-foot, such as a field covered in water to the depth of one foot. Allow questions 1, 2, 7, and 8 to be answered in short phrases or as a labeled sketch. Provide a sentence frame for question 8, such as "When the upstream district ____, the town downstream must ____."

Extensions

Have students compare two delivery rules on the same set of orders. Under the first rule the oldest right is filled completely before any newer right receives water. Under the second rule every farm receives the same percent of its order. Students apply both rules to a short order list the teacher supplies, then write which rule they would choose and which group of growers each rule protects.