Graphic organizer Grade 12 Careers & CTE
Yarrowfield Well Field: From Nitrate Trend to a New Job Description
A grade 12 careers cause-and-effect chain organizer tracing how a rising nitrate trend at a fictional well field turns into new tasks, roles, credentials, and costs.
Objectives
- Students will trace how a groundwater quality trend becomes an operating decision and then a staffing decision.
- Students will compare response options by annual cost and state which cost the next step adds.
- Students will name the credential and the tracked quantity attached to each new duty.
Vocabulary
- Action level
- A trigger number in lead and copper testing. If too many homes test above this level, the utility must take steps like improving treatment and telling the public.
- Ion exchange
- A water treatment method that swaps unwanted charged particles in the water for harmless ones held on tiny resin beads. It is used to remove PFAS and to soften hard water.
Also: alluvial aquifer, blending, source water protection, certified crop adviser
Teacher overview
This organizer is a cause-and-effect chain that follows one groundwater problem from the aquifer to a posted job description. Students work from a short data set for a fictional utility, the Yarrowfield Water District, and complete eight linked steps, each with a cause, an effect, the person who decides or acts, and the quantity the district would track to know whether the step is working. Students often picture a water quality problem as ending when treatment is installed, and then miss the years of sampling, reporting, and landowner work that follow. The chain is built so that the staffing links come after the treatment link, which makes that continuing work visible.
Organizer
Read the background, then complete the chain. Write one short phrase in each cell.
Background: the fictional Yarrowfield Water District
Yarrowfield serves about 9,500 people from three wells in a shallow alluvial aquifer. Row-crop acreage upgradient of the well field has expanded over the past decade. Nitrate at Well 3 has risen from 4.2 mg/L eight years ago to 8.6 mg/L in the most recent round. The district's own policy sets an internal action level of 8.0 mg/L, which sits below the limit its state enforces and is meant to trigger planning well before compliance is at risk. Wells 1 and 2 have stayed near 2.5 mg/L.
Response options priced by the fictional district's engineer
| Option | What it does | Annual cost |
|---|---|---|
| Blend Well 3 with Wells 1 and 2 | Lowers the nitrate delivered to customers without removing any | $95,000 |
| Add ion exchange treatment at Well 3 | Removes nitrate from the Well 3 stream | $610,000 |
| Drill a deeper well outside the affected zone | Replaces the affected supply | $2.4 million to build, then $140,000 a year |
| Source water protection agreements with upgradient growers | Slows or reverses the loading that caused the trend | $70,000 |
Chain to complete
| Link | Cause | Leads to | Effect | Who decides or acts | Quantity the district tracks |
|---|---|---|---|---|---|
| 1 | Upgradient land use changes | → | |||
| 2 | Nitrate at Well 3 reaches the internal action level | → | |||
| 3 | The district must choose among the four options | → | |||
| 4 | The chosen response creates new daily and seasonal tasks | → | |||
| 5 | The new tasks exceed current staff hours | → | |||
| 6 | The new position requires specific qualifications | → | |||
| 7 | Qualified candidates must be recruited or trained | → | |||
| 8 | Added staffing and operating cost enters the budget | → |
From Water for Schools (waterforschools.org). This material is in the public domain (CC0) and may be copied, edited, and shared freely.
Completed Exemplar
| Link | Cause | Leads to | Effect | Who decides or acts | Quantity the district tracks |
|---|---|---|---|---|---|
| 1 | Upgradient land use changes | → | Nitrate loading to the shallow aquifer rises, and the trend appears first at the well closest to the change | Nobody at the district decides this; the operator observes it in routine sampling | Nitrate in mg/L at each wellhead, plotted by year |
| 2 | Nitrate at Well 3 reaches the internal action level | → | The fictional district's 8.0 mg/L trigger converts a trend into a required planning step, with the 8.6 mg/L result starting the clock | Licensed operator reports the result; the general manager opens a planning file | Number of consecutive rounds at or above 8.0 mg/L |
| 3 | The district must choose among the four options | → | Blending at $95,000 and protection agreements at $70,000 are the least costly per year, and the district adopts both, holding ion exchange at $610,000 in reserve if blending stops being enough | District board, on the engineer's and general manager's recommendation | Annual cost of each added step, and the nitrate delivered to customers in mg/L |
| 4 | The chosen response creates new daily and seasonal tasks | → | Operators calculate and adjust a blend ratio each day, sampling expands from quarterly to monthly at Well 3, and someone must build and maintain agreements with growers | Licensed operator for blending and sampling; a new coordinator for the agreements | Blend ratio, samples collected per month, acres under agreement |
| 5 | The new tasks exceed current staff hours | → | The district adds about eight operator hours a week and creates a half-time source water protection coordinator rather than adding a full operator position | General manager, with the board approving the position | Staff hours per week by task, and vacancy days per position |
| 6 | The new position requires specific qualifications | → | Sampling and blending stay with licensed operators who also hold sampler certification, while the coordinator role calls for agronomy background such as a certified crop adviser credential and experience working with landowners | Human resources, working from the operations manager's task list | Number of staff holding each credential, and credentials expiring within a year |
| 7 | Qualified candidates must be recruited or trained | → | The district posts the coordinator role regionally, and offers current operators paid time and exam fees to add sampler certification rather than hiring from outside | Human resources and the operations manager | Applications per posting, and staff completing each certification per year |
| 8 | Added staffing and operating cost enters the budget | → | The blending, agreements, and new position are proposed together in the rate study so the board sees the full cost of the response rather than the treatment line alone | District board during the annual budget and rate hearing | Total annual program cost, and cost per million gallons delivered |
Differentiation
Support
Give these students the Effect column already completed for the fictional Yarrowfield chain so they supply only the actor and the tracked quantity, and provide a word bank of six roles and six quantities. Complete links 1 and 2 together as a class before students continue.
Extension
Ask students to redraw links 3 through 8 for the case where blending stops working because Well 1 also crosses the fictional district's 8.0 mg/L action level. They should state which option the district turns to next, what it costs each year, and which of the eight links change as a result.
ELL supports
Pre-teach aquifer, blending, action level, agreement, and credential with short definitions and a simple cross-section showing three wells, the crop field above them, and an arrow for nitrate moving downward. Allow noun-phrase answers in every cell, and pair students so one reads the background aloud while the other records.
Extensions
Many states publish source water assessment reports naming the contaminants that threaten each public water supply. Have students locate one report for any community, identify the leading threat named there, and write the first three links of a chain like this one for that system.