Project Grade 10 Careers & CTE
Cawsley Orchards' Allotment: An Irrigation Technician Project
A grade 10 careers project where teams work as irrigation technicians, sizing a season water plan for four orchard blocks under an allotment and a retrofit budget.
Objectives
- Students will convert crop water demand in inches into acre-feet and gallons for a block of stated acreage.
- Students will compare irrigation upgrades by dollars spent per acre-foot of water saved.
- Students will produce a season irrigation schedule and a weekly service log that fit a stated water allotment.
Vocabulary
- Acre-foot
- The amount of water it takes to cover one acre of land, about the size of a football field, one foot deep. Western states use acre-feet to measure large amounts of water.
Also: allotment, distribution uniformity, micro-sprinkler, deficit irrigation, service log
Teacher overview
An irrigation technician spends a season deciding how much water each block of a farm receives, how it is delivered, and which equipment is worth fixing. Over five sessions, teams take that role at the fictional Cawsley Orchards and plan a whole irrigation season against a fixed water allotment. The misconception this project corrects is the belief that a field needs only the water the crop uses, when in practice a system delivers water unevenly, so the volume pumped is always larger than the volume the trees take up, and the size of that gap depends on the equipment. Teams deliver a season plan, an upgrade recommendation, and a filled weekly service log.
Project Brief
Driving question: How can the fictional Cawsley Orchards grow all four blocks on its allotment, and which upgrades are worth buying to get there?
Scenario: Cawsley Orchards is a fictional 60-acre orchard. It buys water from the fictional Halbourne Valley Irrigation District. Teams work as the orchard's irrigation technician. The owner wants a written season plan before the first watering.
Given data, from the fictional district's block sheet:
| Block | Acres | Crop | System | Season crop need | Distribution uniformity |
|---|---|---|---|---|---|
| 1 | 18 | Apples | Micro-sprinkler | 30 inches | 78% |
| 2 | 14 | Pears | Flood furrow | 28 inches | 55% |
| 3 | 16 | Apples | Drip | 30 inches | 90% |
| 4 | 12 | Cherries | Micro-sprinkler | 26 inches | 80% |
Upgrade price sheet, set for this fictional scenario:
| Upgrade | Price | Effect |
|---|---|---|
| Convert Block 2 to micro-sprinkler | $2,200 per acre | Uniformity rises to 80% |
| Convert Block 2 to drip | $3,400 per acre | Uniformity rises to 90% |
| Replace worn nozzles in Block 1 | $140 per acre | Uniformity rises to 85% |
| Add pressure regulators in Block 4 | $260 per acre | Uniformity rises to 88% |
| Install soil moisture sensors | $85 per acre | Cuts applied water on that block by 8% |
Limits, all set for this fictional scenario:
- The season allotment is 160 acre-feet for the whole orchard.
- The upgrade budget is $45,000, and it may not be exceeded.
- Gross water for a block equals the crop need divided by the uniformity.
- One acre-foot covers one acre one foot deep, so twelve inches of water on one acre is one acre-foot.
- One acre-foot equals 325,851 gallons.
- Any block watered below its crop need must be flagged in the plan, because short watering costs fruit size.
Final deliverable: A season packet for the orchard owner. It holds four parts. Part one is a table of gross water for each block before upgrades. Part two is the upgrade recommendation, with dollars spent per acre-foot saved. Part three is the season plan after upgrades, showing total acre-feet against the allotment. Part four is one week of the technician's service log, filled in.
Milestones
Session 1, find the demand: Teams turn each block's crop need into acre-feet. They use the depth of water over the block's acres. Output: a four-row table of crop demand in acre-feet.
Session 2, find the gross draw: Teams divide each block's demand by its uniformity. That gives the water that must leave the district turnout. Teams total the four blocks and compare the total to the allotment. Output: a gross water table, a total, and the size of the gap.
Session 3, price the upgrades: Teams find the acre-feet saved by each upgrade. They find the cost of each upgrade. They then divide cost by acre-feet saved. Output: a ranked list of upgrades by dollars per acre-foot saved.
Session 4, build the season plan: Teams choose a set of upgrades inside the budget. They rebuild the gross water table with the new uniformity figures. If the total still sits above the allotment, they must flag which block gets short water and by how much. Output: a season plan with totals, the budget used, and any flags.
Session 5, write the log and present: Teams fill one week of the service log with the checks a technician performs, including filter flushing, pressure readings, and leak repairs. They then present the packet to the class, who act as the owner. Output: a completed service log week and a 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 | Emerging | Developing | Proficient | Advanced |
|---|---|---|---|---|
| Demand and unit work | Conversions are missing or inches are treated as volume | Some blocks are converted correctly, yet the table is incomplete | All four blocks are converted correctly into acre-feet | Conversions are correct and at least one block is also reported in gallons with the reason for the choice |
| Gross water and uniformity | Uniformity is ignored, so demand and gross water are treated as the same | Uniformity is used on some blocks only, or is multiplied instead of divided | Gross water is computed correctly for all four blocks and totaled | Gross water is correct and the team explains why the worst block costs the most water |
| Upgrade analysis | Upgrades are chosen with no figures behind them | Costs or savings are computed, yet not both, so no ranking is possible | Every upgrade is ranked by dollars per acre-foot saved and the chosen set fits the budget | The ranking is complete, the chosen set fits the budget, and the team says which upgrade it rejected and why |
| Season plan and service log | The plan gives no total, or the log is blank | The plan totals the acre-feet, yet does not compare them to the allotment, or the log lists only one task | The plan compares the total to the allotment, flags any short watering, and the log covers a full week of checks | The plan does all of that and the log includes a backflow assembly test, naming the certification a technician needs to perform it |
Differentiation
Support
Give teams Block 3 worked through both steps, from inches to acre-feet and then to gross water, as a model to copy for the other three blocks. Provide a ranking table with the cost column already filled so teams can focus on the savings and the division.
Extension
Ask teams to find the allotment the orchard would need with no upgrades at all, then to state how many dry seasons of purchased extra water it would take before the upgrade set pays for itself at a stated water price of $95 per acre-foot.
ELL supports
Pre-teach allotment, uniformity, turnout, and service log with a labeled sketch of a block, a turnout valve, and a drip line. Allow the presentation to be given from the packet's tables with short spoken notes, and supply a sentence frame for reporting the gap between demand and allotment.
Extensions
Teams can redo the plan for a drought year in which the district cuts every allotment by one fifth, then describe which block they would fallow and what that decision would cost the orchard. A district field technician or a farm manager could review two packets and describe how real allotments are measured and recorded.