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Quiz & test questions Grade 9 Careers & CTE

Whelkmere Water Works: A Distribution Operator Skills Quiz

A 40-point grade 9 careers quiz on the distribution operator's job at a fictional hillside utility, mixing role questions with pressure, flow, and storage math.

Objectives

  1. Students will distinguish distribution operator duties from treatment plant operator duties.
  2. Students will convert between feet of head and pounds per square inch in a distribution system.
  3. Students will calculate flushing flow, storage duration, and valve maintenance workload from stated system data.

Vocabulary

Pressure zone
A pressure zone is a section of a water system that a utility manages separately because it sits at a different elevation than the rest of the town. Utilities create pressure zones so that water pressure stays safe and steady for everyone, whether they live at the bottom of a hill or near the top.
Valve exercising
Opening and closing each underground valve on a schedule to make sure it still works. A stuck valve can turn a small pipe break into a big emergency.
Dead-end main
A dead-end main is a section of water pipe that stops instead of connecting to another pipe on the far end, so water can only flow in and out from one direction. Water can sit still longer in a dead-end main, so utilities flush them regularly to keep the water fresh.

Also: distribution operator, head, return to service

Teacher overview

This quiz covers the first unit on distribution system work, the part of a water utility that begins where the treatment plant ends. It is worth 40 points across 14 items, combining multiple choice, short answer, and computation, and it should take about 50 minutes with a calculator. Every item is set at the fictional Whelkmere Water Works, so students carry one system through the whole quiz. Teaching note: students routinely treat pressure and elevation as separate facts about a customer's house, when the pressure at a connection is set by how far the tank's water surface stands above it, which is why a house partway up a hill reads lower even though no operator changed anything. Items 3 and 5 are built to expose that, and a student who answers item 3 correctly but cannot explain item 5 has not yet made the connection.

Whelkmere Water Works: A Distribution Operator Skills Quiz — Grade 9 Careers & CTE
Name: ____________________________ Date: ______________

Assessment

Use the following information about the fictional Whelkmere Water Works for every item. Show your work and write the unit beside every number you calculate.

  • Whelkmere's elevated tank holds water whose surface sits 118 feet above the Maple Row service connection.
  • The utility's written policy keeps service pressure between 45 and 75 psi at the customer's connection.
  • Conversions Whelkmere's operators use: one foot of head equals 0.433 psi, and one psi equals 2.31 feet of head.
  • One cubic foot per second equals 448.8 gallons per minute. A circular pipe's area in square feet equals 0.785 times the diameter in feet squared.
  • Whelkmere's ground storage tank holds 750,000 gallons when full.
  • The distribution system contains 1,240 valves, and policy requires each valve to be exercised once every four years.
  • After any main break, Whelkmere's procedure requires the crew to isolate the break, repair and disinfect the pipe, collect two bacteriological samples 24 hours apart that both come back absent of total coliform, and file the return-to-service record before the main is reopened to customers.
  1. Which task is normally the distribution operator's responsibility rather than the treatment plant operator's? (2 points)
    A. Adjusting the coagulant dose at the rapid mix basin
    B. Exercising valves and flushing dead-end mains in the street
    C. Backwashing a filter at the end of its run
    D. Calibrating the raw water turbidimeter
  2. Whelkmere's job posting for a distribution operator lists a state distribution license, a commercial driver license, and a confined space entry card. Which statement best describes how someone without a license usually enters this work? (2 points)
    A. The state issues the license after a background check, so a new hire can start licensed.
    B. The new hire works as an operator in training under a licensed operator, then sits for the state exam after the required experience is documented.
    C. A four-year engineering degree replaces the license in every state.
    D. The license is optional as long as a licensed operator signs the monthly report.
  3. The tank's water surface is 118 feet above the Maple Row connection. Using 0.433 psi per foot, calculate the pressure at Maple Row. (3 points)
  4. Whelkmere's policy sets a minimum service pressure of 45 psi. Using 2.31 feet of head per psi, write and solve an equation for the height of water above a connection that this minimum requires. (3 points)
  5. The Kestrel Hill connection sits 63 feet higher than the Maple Row connection, while the tank's water surface remains 118 feet above Maple Row. Using 0.433 psi per foot, calculate the pressure at the Kestrel Hill connection. (3 points)
  6. A pressure logger at the Cobb Street connection records 38 psi during the morning peak. State whether that reading meets Whelkmere's policy band of 45 to 75 psi. (2 points)
  7. Cobb Street sits near the top of a long rise and reads below the policy band every morning. Which response best matches what a distribution operator is hired to do? (3 points)
    A. Close the valve feeding Cobb Street until pressure rises in the rest of town.
    B. Record the reading, notify the supervisor, and recommend that the utility study a booster pump station or a separate pressure zone for the high ground.
    C. Tell Cobb Street residents to buy their own pumps.
    D. Raise the chlorine dose at the plant so the water moves through the pipe faster.
  8. A crew flushes a 12-inch main, which is 1 foot in diameter, at a velocity of 2.5 feet per second. Using an area of 0.785 times the diameter squared, calculate the flow in cubic feet per second. (4 points)
  9. A flushing flow measures 1.96 cubic feet per second. Using 448.8 gallons per minute per cubic foot per second, convert that flow to gallons per minute. (3 points)
  10. A hydrant flushes at 880 gallons per minute for 12 minutes. Calculate the volume of water discharged. (3 points)
  11. Whelkmere's ground storage tank holds 750,000 gallons and the town draws 350 gallons per minute overnight. Calculate how many hours the full tank would supply that draw. (4 points)
  12. Whelkmere has 1,240 valves and exercises each one once every four years. Calculate how many valves the crew must exercise in one year. (3 points)
  13. A crew exercises 310 valves in a year and spends 20 minutes on each valve. Calculate the total hours of work that represents. (3 points)
  14. Using Whelkmere's main break procedure above, state what must be true of the bacteriological samples before the repaired main may be returned to service. (2 points)

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: B.
    Exercising valves and flushing dead-end mains happen in the street, in the distribution system. The other three choices are all tasks inside the treatment plant.
  2. Answer: B.
    Entry into operations work normally runs through an operator-in-training position, with the state license earned by exam after a documented period of experience under a licensed operator. Choice A skips the exam, choice C treats a degree as a license, and choice D would leave the system without a licensed person doing the work.
  3. Answer: 51.1 psi.
    Multiply the head by the conversion: 118 feet times 0.433 psi per foot equals 51.094 psi, which rounds to 51.1 psi.
  4. Answer: 104 ft.
    Let h be the height of water in feet. Then h equals 45 psi times 2.31 feet per psi, so h equals 103.95 feet, which rounds to 104 feet.
  5. Answer: 23.8 psi.
    Kestrel Hill is 63 feet higher than Maple Row, so the water surface stands only 118 minus 63, or 55 feet, above it. Then 55 feet times 0.433 psi per foot equals 23.815 psi, which rounds to 23.8 psi.
  6. Answer: No.
    A reading of 38 psi falls below the policy minimum of 45 psi, so the connection is outside the band even though it is above the 20 psi floor that prevents backflow.
  7. Answer: B.
    Recording the reading, reporting it, and recommending a study stays inside what a distribution operator is authorized to do. Choice A would make pressure worse for Cobb Street, choice C moves a utility duty onto customers, and choice D confuses disinfection with hydraulics.
  8. Answer: 1.96 cfs.
    The area is 0.785 times 1 foot squared, which is 0.785 square feet. Flow equals area times velocity, so 0.785 square feet times 2.5 feet per second equals 1.9625 cubic feet per second, which rounds to 1.96 cfs.
  9. Answer: 880 gpm.
    Multiply the flow by the conversion: 1.96 cubic feet per second times 448.8 gallons per minute per cubic foot per second equals 879.6 gallons per minute, which rounds to 880 gpm.
  10. Answer: 10,560 gallons.
    Multiply the rate by the time: 880 gallons per minute times 12 minutes equals 10,560 gallons.
  11. Answer: 35.7 hours.
    Divide the volume by the rate: 750,000 gallons divided by 350 gallons per minute equals 2,142.9 minutes. Then divide by 60 minutes per hour to get 35.7 hours.
  12. Answer: 310 valves.
    Divide the total by the cycle length: 1,240 valves divided by four years equals 310 valves per year.
  13. Answer: 103.3 hours.
    Multiply and convert: 310 valves times 20 minutes per valve equals 6,200 minutes, and 6,200 divided by 60 minutes per hour equals 103.3 hours.
  14. Answer: Both samples must show total coliform absent.
    The procedure calls for two bacteriological samples collected 24 hours apart, and both must come back absent before the return-to-service record is filed and the main is reopened.

Differentiation

Support

Provide a conversion card showing the two pressure conversions with one worked example each, so students spend their time deciding which conversion applies rather than recalling it. Allow these students to answer items 1, 2, 6, 7, and 14 first, since those items test the role rather than the arithmetic. On item 5, supply the subtraction 118 minus 63 already written in, which is the step most students miss at the fictional Whelkmere system.

Extension

Ask these students to find the elevation above the Maple Row connection at which a home would fall below the fictional utility's 45 psi minimum, then to state how many feet of that rise still sit above the 20 psi floor that prevents backflow. Have them write two sentences on what the utility would have to build to serve homes above that line.

ELL supports

Pre-teach head, pressure zone, exercising a valve, dead-end main, and return to service with a simple side-view sketch of the fictional Whelkmere tank, one house at the bottom of the hill, and one house near the top. Provide a sentence frame for items 6 and 14: "The policy says ___, the reading shows ___, so the operator must ___." Allow answers to computation items to be shown as labeled arithmetic rather than sentences.

Extensions

Have students compare their item 5 result against the policy band and write the two-sentence entry a distribution operator would put in the fictional Whelkmere daily log, naming the reading, the location, and the person notified. A log entry is the record an inspector reads first during a system review, and writing one is closer to the job than the arithmetic that precedes it.