Project Grade 5 Engineering & Design
Rushbeck Brook Sediment Plan: A Grade 5 Site Design Project
A four-session grade 5 project where teams design, model, test, and revise a mud-control plan for a fictional building site above a brook, then pitch it.
Objectives
- Students will restate a town's mud rule and spending limit as criteria and constraints.
- Students will price two sediment control plans and choose one with a written reason.
- Students will test a model plan on a slope and name the point where mud got through.
- Students will revise the plan at that failure point and present it to a fictional board.
Vocabulary
Key words: sediment, silt fence, wattle, runoff, criteria, constraint
Teacher overview
The driving question is this: how do you keep the soil on a bare building site from washing into the stream next door during the first hard rain? Teams in the fictional town of Cobbledown design a sediment control plan for a new bus garage on a hillside above Rushbeck Brook, price it against a fixed spending limit, build and test a model of it on a sloped tray, and revise it where the mud got through. The final deliverable is a labeled site plan, a cost table, and a two-minute pitch to a fictional planning board.
A misconception worth correcting early: students hear "pollution" and picture something poured out of a pipe, so bare dirt washing downhill does not look like pollution to them at all. Muddy water is a common water quality problem in rivers and streams, and the reason is physical rather than chemical. Fine soil hanging in the water blocks sunlight, settles on the gravel where fish lay eggs, and fills in the deep pools a stream needs. Say this before the first session, and return to it when a team's jar of runoff comes out brown. A second point teachers should press on: teams reliably build a wall across the bottom of their slope and stop there. Ask them where the water enters the site, not only where it leaves, because slowing water at the top of a slope is usually cheaper than catching it at the bottom.
This project runs across four sessions of about 45 minutes each.
Project Brief
Your client. The Cobbledown school district is building a new bus garage. The lot is 200 feet long and 150 feet wide. It sits on a slope. All of the dirt has been scraped bare. At the bottom of the slope, along the 150-foot edge, runs Rushbeck Brook. Cobbledown, the brook, and the garage are all fictional, and so are the prices below.
The driving question. How can we keep bare soil from washing into Rushbeck Brook during the first hard rain, without blocking the work site?
Criteria. Your plan must do all three of these.
- Cover the whole 150-foot downhill edge, so no gap is left open to the brook.
- Slow the water somewhere on the slope, not only at the bottom edge.
- Be ready before the first rain, which means one work day to put in place.
Constraints. Your plan must stay inside all three of these limits.
- Spend $600 or less in total.
- Leave the 40-foot truck gate on the uphill side open and clear.
- Use only items from the price list.
Price list.
- Silt fence, a buried cloth wall on stakes: $3 for each foot.
- Straw wattle, a 10-foot roll that lies on the ground: $25 each.
- Gravel entry pad, 20 feet by 20 feet, at the gate: $150.
- Seeded straw blanket, spread over bare dirt: $40 for each 100 square feet.
- Small settling pond dug at one corner: $250.
What you turn in. A poster with a labeled site plan drawn to a stated scale, a cost table that adds to $600 or less, one paragraph naming the failure point you found in your test and what you changed, and a two-minute pitch to the planning board.
Milestones
- Session 1: Define the problem. Mark the site map with arrows showing which way water runs. Write the three criteria and the three limits in your own words. Then find one real example of a community keeping soil out of a stream, drawing on two sources you can name, and write two sentences on what that community did.
- Session 2: Draft and price two plans. Sketch two different plans on the site map. Price each one in a cost table. Circle the plan you will carry forward and write one sentence saying which criterion decided it. Turn in both sketches, not just the winner.
- Session 3: Build and test the model. Build your chosen plan on a tray of soil propped at one end. Pour the same amount of water from the same spot as every other team. Catch the runoff in a clear jar. Draw the tray and mark with an X the spot where the most mud got past your controls.
- Session 4: Revise and pitch. Change your plan at the X you marked, and only there. Redraw the site plan with the change labeled. Update the cost table so it still fits the limit. Give a two-minute pitch to the planning board that names your failure point, your change, and the criterion each control is meeting.
From Water for Schools (waterforschools.org). This material is in the public domain (CC0) and may be copied, edited, and shared freely.
Rubric
| Criterion | Emerging | Developing | Proficient | Advanced |
|---|---|---|---|---|
| Criteria and constraints | The plan restates fewer than three of the six rules | All six rules are listed, but some are copied word for word | All six rules are restated in the team's own words and each control on the map is matched to one of them | Every control is matched to a rule, and the team explains which rule was hardest to meet and why |
| Coverage of the downhill edge | Gaps are left open along the edge to the brook | The edge is covered but the truck gate is blocked or a corner is left open | The full 150-foot edge is covered, the gate stays clear, and water is slowed somewhere above the edge as well | The plan covers the edge, keeps the gate clear, slows water on the slope, and explains why the uphill control reduces the load on the bottom one |
| Cost table | The table is missing or the total is over the limit | The total is inside the limit but the arithmetic has errors | The table lists every item with its price, adds correctly, and comes in at or under the limit | The table is correct and the team shows a second version it rejected, with a sentence on the trade-off |
| Test and revision | No failure point is marked, or the model was not tested | A failure point is marked but the revision changes several things at once | The X marks one failure point, and the revision changes that one place, with the rest of the design held steady | The revision is targeted, and the team predicts what the next failure point would be if the design were tested again |
| Pitch to the board | The pitch does not describe the plan | The pitch describes the plan but does not connect controls to rules | The two-minute pitch names the failure point, the change, and the rule each control meets | The pitch does all of that and answers a board member's question with evidence from the team's own test |
Differentiation
Support
Give these teams a site map with the slope arrows already drawn and the downhill edge highlighted, so session 1 begins at the rule-writing step. Provide a cost table with the item names and unit prices already printed, leaving only the quantity and total columns blank. During the model test, assign one team member to pour and one to watch a single marked zone, which keeps the observation task small enough to report clearly.
Extension
Ask these teams to add a second, harder storm to session 3: the same tray, the same starting point, but twice the water poured in the same amount of time. They should record whether the failure point moves, then write a short recommendation on whether Cobbledown should design for the common storm or the rare one, and name what the town gives up either way.
ELL supports
Pre-teach "sediment," "silt fence," "wattle," and "slope" with a labeled cross-section drawn on the board and with the actual model materials in hand. Provide the pitch as a four-sentence frame: "Our site problem is ___ . Our plan uses ___ . In our test, mud got through at ___ . We changed ___ ." Allow teams to present in pairs, with one partner pointing at the poster while the other speaks.
Extensions
Students can look for a building site near the school and photograph or sketch the controls already in place there, from outside the site fence and with an adult, then match each one to a criterion from this brief. Many state environmental agencies publish a short illustrated guide to erosion control for builders, and comparing one page of that guide with the class designs shows students that their price list, while simplified, mirrors a real set of choices.