Graphic organizer Grade 10 Engineering & Design
Quarryfen Wellfield Protection Zones: A Land-Use Organizer
A grade 10 organizer mapping four wellhead protection zones around a fictional public well, matching the threats in each zone to controls and to who enforces them.
Objectives
- Students will distinguish wellhead protection zones drawn by fixed distance from zones drawn by groundwater travel time.
- Students will match a land use in each zone to a control and to the agency that can enforce it.
- Students will assign specific sites to the correct protection zone using travel time rather than distance alone.
Vocabulary
Key words: wellhead protection, time of travel, contribution area, setback, secondary containment, zoning overlay
Teacher overview
Protecting a public well is a land-use problem before it is a treatment problem, because a contaminant that reaches the aquifer is far more expensive to remove than to keep out. This organizer is a concentric-zone frame: four nested rings around a fictional wellfield, each defined by how long groundwater takes to reach the well, with a threat column, a control column, and an enforcement column running across them. The nesting matters because it shows why controls tighten as travel time shortens, since a spill two years out gives a utility time to respond while a spill inside the sanitary setback does not. A misconception worth naming first is that the zones are simple circles measured in feet; only the innermost ring is a fixed radius, and the others follow the direction groundwater actually moves, which usually makes them long and narrow rather than round.
Organizer
Complete every cell in both tables. The zone definitions and the site list are given below.
Case notes. Quarryfen is a fictional town whose public supply comes from a single well in a sand and gravel aquifer. The county defines four protection zones. Zone 1 is a fixed radius of 200 feet around the wellhead. Zone 2 covers everything within a 200-day groundwater travel time. Zone 3 covers everything within a 5-year travel time. Zone 4 is the remainder of the area that contributes water to the well. Groundwater moves toward the well from the northwest, so the zones stretch in that direction rather than forming circles.
| Zone | How the boundary is drawn | Land uses and threats commonly found here | Controls the utility or county can apply | Who enforces the control | What to monitor |
|---|---|---|---|---|---|
| Zone 1 | |||||
| Zone 2 | |||||
| Zone 3 | |||||
| Zone 4 |
Site triage. Assign each site to a zone, then name the single control you would apply first.
| Site in Quarryfen | Distance from the well | Travel time | Zone | First control |
|---|---|---|---|---|
| Gravel drive and parking beside the wellhouse | 80 feet | days | ||
| Eleven homes on individual septic systems | 600 feet | 150 days | ||
| An unused farm well, uncapped | 900 feet | 220 days | ||
| A school bus garage with an above-ground diesel tank | 1,400 feet | 3 years | ||
| A county road salt pile under an open shed | 2,600 feet | 6 years |
From Water for Schools (waterforschools.org). This material is in the public domain (CC0) and may be copied, edited, and shared freely.
Completed Exemplar
Case notes. Quarryfen is a fictional town with one public supply well, four county protection zones, and groundwater arriving from the northwest.
| Zone | How the boundary is drawn | Land uses and threats commonly found here | Controls the utility or county can apply | Who enforces the control | What to monitor |
|---|---|---|---|---|---|
| Zone 1 | A fixed 200-foot radius around the wellhead, not based on travel time | The wellhouse itself, vehicle parking, mowing chemicals, floor drains, and surface water ponding against the casing | Utility ownership of the parcel, fencing, no chemical storage or parking, grading so surface water drains away, and a sealed casing annulus | The utility, with the state drinking water program during sanitary surveys | Casing and seal condition, standing water after storms, and routine bacteriological samples |
| Zone 2 | Everything within a 200-day groundwater travel time, drawn upgradient toward the northwest | Septic systems, sanitary sewer lines, livestock yards, stormwater infiltration basins, and small fuel deliveries | Connecting homes to sewer or limiting septic density, inspecting and lining sewer lines, prohibiting infiltration basins, and setting manure setbacks | The county health department and the local planning board | Bacteriological results, nitrate trend, and sewer inspection records |
| Zone 3 | Everything within a 5-year groundwater travel time | Fuel storage tanks, machine shops, vehicle maintenance, agricultural chemical mixing, and abandoned wells that bypass the confining soil | Secondary containment around tanks, spill response plans, hazardous material permits, and decommissioning of abandoned wells | The fire marshal for tanks, the county health department for wells, and the state for permitted facilities | Volatile organic compound sampling, tank inspection reports, and a current inventory of abandoned wells |
| Zone 4 | The remainder of the area contributing water to the well, beyond the 5-year travel time | Large-scale agriculture, road corridors and winter salting, new residential development, and gravel extraction | A zoning overlay reviewing new uses, agricultural best management practices, covered salt storage, and an emergency response agreement with the county | The planning and zoning board, with the county highway department for salt storage | Chloride trend, pesticide screening, and periodic updates to the travel-time model as pumping changes |
Site triage.
| Site in Quarryfen | Distance from the well | Travel time | Zone | First control |
|---|---|---|---|---|
| Gravel drive and parking beside the wellhouse | 80 feet | days | Zone 1, since it falls inside the fixed 200-foot radius | Move parking off the parcel and regrade so runoff drains away from the casing |
| Eleven homes on individual septic systems | 600 feet | 150 days | Zone 2, since 150 days is inside the 200-day boundary | Extend sewer to the homes, or require inspection and a density limit until that is possible |
| An unused farm well, uncapped | 900 feet | 220 days | Zone 3, since 220 days is past the 200-day boundary but well inside 5 years | Decommission the well by sealing it, because an open bore is a direct path past the protective soil |
| A school bus garage with an above-ground diesel tank | 1,400 feet | 3 years | Zone 3, since 3 years is inside the 5-year boundary | Build secondary containment around the tank and file a spill response plan |
| A county road salt pile under an open shed | 2,600 feet | 6 years | Zone 4, since 6 years is beyond the 5-year boundary | Enclose the salt storage on a sealed pad and begin tracking the chloride trend in the well |
Differentiation
Support
Give these students the zone column and the boundary column already filled in, so their work begins with threats and controls. Provide a word bank of controls, including fencing, sewer extension, secondary containment, well decommissioning, covered salt storage, and zoning overlay, and let them match rather than generate. For the site triage, supply the zone assignments and ask only for the first control.
Extension
Ask these students to explain why the uncapped farm well at 900 feet may deserve faster action than the diesel tank at 1,400 feet, even though the tank holds a larger volume of a more obvious contaminant. Have them also redraw the zone boundaries for a case in which the utility doubles its pumping rate, and state which sites would change zones.
ELL supports
Provide a plan-view sketch showing the well, an arrow for the direction groundwater moves, and the four zones drawn as stretched shapes rather than circles, with each zone labeled. Post a term strip pairing travel time with how long water takes to reach the well, setback with required distance, containment with a wall that holds a spill, and overlay with an extra zoning rule.
Extensions
Have students find whether their own state publishes wellhead or source water protection area maps and locate the nearest mapped area, then list which of the four zone types the state uses. Students can also interview a local planning official about how a proposed business near a public well is reviewed, and add a column to the organizer recording what evidence that review requires an applicant to submit.