Writing prompt Grade 10 English Language Arts
How Cullenford Listens for Leaks: An Explanatory Prompt
A grade 10 ELA writing prompt in which students explain, for a town newsletter, how a fictional water department finds buried leaks that never reach the surface.
Objectives
- Students will explain a technical process accurately for readers who have no background in it.
- Students will organize an explanation so that each paragraph advances one idea.
- Students will define technical terms in context without stopping the explanation.
Vocabulary
- Service line
- A service line is the small pipe that connects the water main under the street to the plumbing inside one home or building. It is the last leg of the trip water makes to your tap.
Also: distribution main, acoustic survey, correlator, night flow
Teacher overview
Most water leaks never reach the surface. Water escaping a buried pipe usually travels along the trench and into the soil, so a pipe can lose water for months with nothing visible above it. This prompt asks students to explain how a water department finds those leaks and why the search is worth the labor. The writing task is explanatory rather than persuasive, so students practice making an unfamiliar technical process clear to a reader who has no background in it.
Prompt
Background
The fictional town of Cullenford owns about ninety miles of water main. Some of that pipe was laid in the 1930s. Nationally, a water main breaks roughly every two minutes, and Cullenford loses a few each winter when the ground freezes and shifts.
A break that erupts through pavement gets fixed the same day. The harder problem is the leak that does not surface. Water leaving a small crack follows the gravel bedding around the pipe, soaks into the soil, and reaches a storm drain or a stream without ever showing on the street. Cullenford pumps that water, treats it, and never delivers it.
Cullenford's water department finds these leaks in three ways.
The first is arithmetic. The department has divided the town into eight metered zones. A meter at the entrance to each zone records how much water goes in. Late at night, when almost no one is using water, the flow into a zone should drop to nearly nothing. When a zone's night flow stays high week after week, something in it is running that nobody turned on.
The second is listening. A leak makes a steady sound as water forces its way out of a pressurized pipe, and that sound travels along the metal. Technicians work at night, when traffic is quiet. They place a sensitive listening device on hydrants and valve covers along a street and note where the sound is loudest.
The third is timing. A correlator uses two sensors placed on the pipe on either side of the suspected leak. The leak sound reaches one sensor slightly before the other, and the instrument uses that difference, along with the pipe's length and material, to calculate where the leak sits between them. A good correlation can put a crew within a few feet of the spot before anyone opens the pavement.
Homeowners face a smaller version of the same problem. A running toilet or a dripping outdoor spigot is easy to ignore, yet household leaks waste an average of nearly 9,400 gallons a year.
Your task
Write an explanatory article of 600 to 750 words for the Cullenford town newsletter, whose readers are residents with no technical background. Explain how the water department finds leaks that never surface, and explain why the town does this work. Define each technical term the first time you use it. Your article should inform rather than argue, and it should be accurate to the background above. Do not invent figures the background does not give you.
Planning Organizer
Complete every row before drafting. The rows match the criteria your article will be scored on.
| Planning element | What to write here | My notes |
|---|---|---|
| Controlling idea | One sentence naming what the article will explain and why it matters to a Cullenford reader. | |
| Reader's starting point | Two things a resident probably already believes about leaks, and one thing the article has to correct. | |
| Paragraph plan | One line per paragraph, each naming the single idea that paragraph carries. | |
| Evidence and detail | Three specific details from the background, with the paragraph each belongs in. | |
| Terms to define | Each technical term you will use, with the plain-language definition you will give in context. | |
| Closing | The idea the last paragraph leaves the reader with, stated in one sentence. |
From Water for Schools (waterforschools.org). This material is in the public domain (CC0) and may be copied, edited, and shared freely.
Exemplar & Rubric
Exemplar response
Cullenford's water department spends several nights each month walking quiet streets and listening to hydrants. The work looks strange to anyone who happens to be awake for it, and it exists because most leaks in a water system never announce themselves.
When a main breaks under a street, everyone knows. Water comes up through the pavement, a crew arrives, and the road is closed by lunchtime. Those breaks are dramatic and, in a way, easy. The leak that costs a town more is the small one that never surfaces at all. Water escaping a crack in a buried pipe follows the gravel packed around it, spreads into the soil, and often ends up in a storm drain or a stream. The town pumped that water and treated it, and no one ever used it. Cullenford owns about ninety miles of main, some of it laid in the 1930s, so there is a good deal of pipe for a small crack to hide in.
The department starts with arithmetic. The town is divided into eight metered zones, and a meter at the entrance to each zone records the water going in. In the middle of the night, when almost nobody is using water, the flow into a zone should fall close to zero. When it does not, and when it stays high week after week, the department knows something in that zone is running without anyone's help. This night flow, as it is called, does not say where the leak is. It says which part of town to search.
The search itself is done by ear. A pressurized pipe leaking water makes a steady hiss, and that sound carries along the metal of the pipe for a considerable distance. A technician walks a street at night, when traffic noise is lowest, and sets a sensitive listening device on each hydrant and valve cover. The sound is faint and unmistakable once a person has learned it. Marking where it grows loudest narrows the search from a zone to a block.
The last step is a correlator, an instrument that turns the sound into a location. Two sensors are placed on the pipe, one on either side of the suspected leak. Because the leak sits closer to one sensor than the other, the sound arrives at one an instant before the other. The correlator measures that difference and, using the distance between the sensors and the material the pipe is made of, calculates where along the run the leak must be. A good correlation puts the crew within a few feet before a single square of pavement is cut.
The reason for all of this is simpler than the method. Water that leaks out has already been paid for. It was pumped, treated, tested, and pushed through the system, and every one of those steps costs the town money and electricity. A leak that runs for eight months costs eight months of that work for nothing. Finding it early also prevents the larger failure that often follows, since water moving through soil erodes the ground supporting the pipe.
Residents deal with a smaller version of the same problem at home. A toilet that runs quietly, or a spigot that drips into the grass, wastes water nobody notices. Household leaks add up to nearly 9,400 gallons a year on average. The department's advice for a home is the department's own method, scaled down: read the meter before bed, read it again in the morning, and if the number moved while everyone was asleep, something is leaking.
Rubric
| Criterion | Emerging | Developing | Proficient | Advanced |
|---|---|---|---|---|
| Controlling idea | The article names a topic without stating what it will explain. | A controlling idea appears but drifts, and some paragraphs serve a different purpose. | A clear controlling idea is stated early and every paragraph serves it. | The controlling idea is stated early, sustained throughout, and returned to in a closing that adds something rather than repeating. |
| Explanation of the process | One method is mentioned; steps are missing or out of order. | Two methods appear, with a step or a connection between them left out. | All three methods are explained accurately and in a logical order, with the role of each made clear. | The three methods are explained accurately and the article also makes clear how each narrows the search for the next. |
| Use of detail | Few details from the background appear, or a detail is misstated. | Some accurate detail appears, with at least one figure or fact used loosely. | At least four specific details are used accurately and placed where they help the reader. | Details are accurate, well chosen, and elaborated so the reader understands why each one matters. |
| Audience and word choice | Technical terms are used without definition, or the tone assumes expertise. | Some terms are defined, others are not, and definitions interrupt the flow. | Every technical term is defined in context, and the tone suits a general reader. | Definitions are woven in so smoothly that the explanation never stops, and word choice consistently serves a non-technical reader. |
| Conventions | Errors interfere with meaning. | Errors are noticeable but meaning is clear. | Few errors; sentence structure is varied and controlled. | Nearly error-free, with sentence structure used deliberately to manage emphasis and pacing. |
Differentiation
Support
Give these students a completed paragraph plan row for the first two paragraphs and a shortened target of 400 to 500 words. Provide the three methods as labeled cards to sequence physically before drafting, and supply two model definitions written in context for terms they can reuse.
Extension
Ask students to add a final section explaining what the department cannot find with these methods, such as a leak on a private service line beyond the town's meter, and to explain what a resident would have to do in that case.
ELL supports
Pre-teach "main," "zone," "night flow," "hydrant," and "correlator" with a simple map showing a metered zone and the hydrants along one street. Provide a definition frame students may reuse: "A ___ is a ___ that ___." Allow the organizer to be completed as labeled sketches with short phrases rather than sentences.
Extensions
Have students read their own home water meter before bed and again in the morning, with a family member's permission, and write a short follow-up paragraph reporting what they found and what it would take to confirm a leak.