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Project Grade 8 Engineering & Design

Stonebeck Creek Monitoring: Designing a Sampling Network

A three-session grade 8 project in which teams design, pilot, and defend a creek sampling network that can detect whether a street-sweeping program is working.

Objectives

  1. Students will write criteria for a monitoring plan before choosing any sampling station.
  2. Students will compare two station layouts against stated criteria and a fixed budget.
  3. Students will pilot a field protocol twice and report how repeatable their readings were.
  4. Students will defend a sampling plan to a panel acting as a watershed council.

Vocabulary

Turbidity
Turbidity is a measure of how cloudy or murky water looks because of tiny particles floating in it. Clear water has low turbidity, and muddy water has high turbidity.

Also: monitoring, sampling station, upstream, downstream, replicate, baseline

Teacher overview

A town that spends money on a pollution control usually wants evidence that the control worked, and that evidence depends heavily on where and when samples were taken. Teams design a sampling network for a creek that runs through a fictional town, pilot their own field protocol to see how repeatable it is, and defend the plan to a panel acting as a watershed council. The misconception to address directly is that more sampling stations always produce better evidence; without a station upstream of the treated area, a hundred downstream samples still cannot separate the effect of street sweeping from the effect of the weather. The deliverable is a monitoring plan packet with a map, a station table, a schedule, a budget table, and a tested protocol.

Stonebeck Creek Monitoring: Designing a Sampling Network — Grade 8 Engineering & Design
Name: ____________________________ Date: ______________

Project Brief

The client. The watershed council of the fictional town of Kilnmore has started sweeping the streets in the Mill Hill neighborhood twice a month to keep grit and leaves out of Stonebeck Creek. The council wants to know whether the sweeping is making a measurable difference.

The driving question. Where, when, and how often should Kilnmore sample Stonebeck Creek so that the council can tell whether street sweeping is working?

What the map shows. Stonebeck Creek runs about 5 km through town. Mill Hill drains to the creek through three storm outfalls, all within the middle 2 km. Six access points are safe and legal to sample: two above Mill Hill, three within it, and one below it, just upstream of the town park.

Your criteria. Your plan will be judged on these, and your team decides how to measure each one.

  1. Comparison power. The plan can separate the effect of sweeping from the effect of rainfall.
  2. Coverage. The plan sees water that has passed the outfalls as well as water that has not.
  3. Workload. The plan fits what volunteers can actually do.
  4. Cost. The plan fits the money the council has.

Your constraints. These come from the council and cannot be changed.

  1. Lab analysis costs $40 per sample, and the council has $2,400 for the year.
  2. Volunteers can sample only on Saturday mornings.
  3. Sampling must run for a full year so that seasons are covered.
  4. No one samples during high water; a scheduled trip that falls on a flood day is skipped and noted.

The deliverable. A monitoring plan packet containing a marked map, a station table listing every station with its purpose, a twelve-month schedule, a budget table that fits the stated money, a written field protocol, and the pilot data showing how repeatable the protocol was. Teams present for five minutes to the panel and must answer one question: what result would convince you the sweeping is not working?

Milestones

  1. Session 1, criteria and two layouts (50 minutes). The team writes its four criteria with a measurement method for each, then sketches two different station layouts on the map and scores both against the criteria. Output: the criteria sheet and a scored comparison of two layouts with a chosen layout circled.
  2. Session 2, pilot the protocol (50 minutes). The team writes a step-by-step field protocol, then runs it twice on the same water sample provided in class, recording both readings. Output: the written protocol plus a short note on how close the two readings were and what the team changed to tighten them.
  3. Session 3, budget, schedule, and council review (50 minutes). The team builds the schedule and budget table, checks them against the constraints, and presents. Output: the finished packet and the five-minute presentation.

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

Rubric
Criterion 4, exceeds 3, meets 2, approaching 1, beginning
Comparison design The plan pairs upstream and downstream stations sampled on the same morning and explains how that pairing separates sweeping from rainfall Upstream and downstream stations are both included and their purpose is stated Stations are all downstream, or the purpose of each is unstated Stations appear chosen at random
Comparing layouts Two layouts are scored against all four criteria and the choice cites the scores Two layouts are compared and one is chosen with a reason A second layout is mentioned but not scored Only one layout was ever considered
Protocol and repeatability Two pilot readings are reported honestly, their difference is discussed, and a specific step was tightened as a result Two pilot readings are reported and the protocol is complete Only one reading was taken, or steps are too vague to repeat No protocol was tested
Meeting the constraints The budget table totals within the stated money, the schedule uses only Saturdays, and the flood rule is written into the plan Budget and schedule meet every constraint One constraint is violated, such as a budget over the stated total Two or more constraints are violated
Presentation The map and tables are readable without narration, and the team answers the council's question with a specific result The packet is complete and the presentation is clear A required part of the packet is missing The packet is incomplete

Differentiation

Support

Give these teams the map with the three outfalls and the six access points already numbered, and a station table with the first row completed as a model, including the purpose column. Provide a budget table with the arithmetic structure laid out so the team fills in counts rather than designing the table.

Extension

Ask the team to add a rule for what to do if a year of data shows no change, distinguishing between the sweeping not working and the plan being unable to detect a change that is real but small. Teams may also propose one low-cost field measurement that could be taken at every visit to stretch the lab budget.

ELL supports

Provide a labeled diagram of a sampling station showing bank, flow direction, outfall, and sampling point, with key terms in the student's home language. Offer sentence frames such as "Station ___ is upstream of ___, so it tells us ___" and "We chose Layout ___ because it scored higher on ___."

Extensions

Ask teams to exchange packets and run a review, each team writing two questions a council member would ask about the other team's plan. Answering another team's questions in writing is usually where students discover that their schedule and their budget table disagree, which is a common flaw in a first monitoring plan.