Grade 11 Lesson plan
Sable Crossing's Growth: Timing a Treatment Plant Expansion
A grade 11 lesson where students model a fictional town's maximum-day water demand exponentially and use logarithms to time a treatment plant expansion.
Common Core Math · High School
HSA-CED.A.1 Create equations and inequalities in one variable
Create equations and inequalities in one variable and use them to solve problems. Include equations arising from linear and quadratic functions, and simple rational and exponential functions.
Why water teaches this standard well
Students write an equation to find how many days remain before a draining reservoir reaches a critical low level, then solve it for the unknown number of days. Modeling a real drawdown as a one-variable equation is a direct, checkable application students can verify against a graph.
Materials tagged with this code are written to the full standard , and each carries a written note explaining the alignment. See how we review materials.
99 materials aligned to HSA-CED.A.1
Lesson plans
Grade 11 Lesson plan
Calverhill's Lead Service Lines: A Fixed Count or a Fixed Percent
A 50-minute grade 11 lesson comparing a linear and an exponential lead service line replacement plan, with logarithms used to find when each plan reaches its target.
Grade 11 Lesson plan
Sedgemount Orchards' Two Wells: Rational Equations for Fill Time
A 50-minute grade 11 lesson where students write and solve rational equations for the time two wells need to fill an irrigation pond, then add a leak to the model.
Grade 12 Lesson plan
Bramleigh Hydrant Flow Test: Flow as a Square-Root Model
A 55-minute grade 12 math lesson in which students model hydrant discharge as a square-root function of pitot pressure and rate a loop against a needed fire flow.
Grade 12 Lesson plan
Fetterly's Rate Increase: When Customers Use Less Water
A 55-minute grade 12 lesson where students model a water utility's revenue against a demand response and solve a quadratic for the rate increase that hits a target.
Grade 10 Lesson plan
Dovegate Cast-Iron Mains: Pipe Lining or Open-Cut Replacement
A grade 10 lesson comparing cured-in-place lining with open-cut replacement for a fictional town's 1920s water mains, using annualized cost and a break-even price.
Grade 9 Lesson plan
Wickhaven's Service Line Ordinance: Who Pays for the Pipe?
A 55-minute grade 9 civics lesson in which students price two lead service line replacement plans for a fictional city and judge which one meets the federal deadline.
Grade 10 Lesson plan
First-Draw vs Flushed: Reading a Home Tap Lead Test
A grade 10 health lesson where students interpret a fictional home's first-draw and flushed lead results against the 15 ppb action level and the 10 ppb 2027 level.
Grade 10 Lesson plan
Carbon Pitcher or Reverse Osmosis? A Home Filter Cost Decision
A grade 10 consumer lesson comparing a fictional home's carbon pitcher and reverse-osmosis costs, the break-even point against bottled water, and a filtered PFAS result.
Grade 11 Lesson plan
Reading the Marsh Hollow Water Report: Chlorine and pH
A grade 11 health lesson where students read a fictional water district's quality report and check its chlorine residual and pH against federal limits.
Grade 11 Lesson plan
Auditing the Escalante Family's Tiered Water Bill in Otterbrook
A grade 11 lesson where students audit a fictional family's tiered water bill, find cost per thousand gallons, and test it against a widely used affordability threshold.
Grade 11 Lesson plan
Choosing a PFAS Filter for the Novak Household in Verde Mesa
A grade 11 health lesson where students weigh a PFAS filter for a fictional household, comparing tap readings to the 4.0 ppt federal limit and two filters' yearly costs.
Grade 10 Lesson plan
Brookfield Crossing Stormwater Runoff Rational Method Lesson
A 50-minute grade 10 lesson using the rational method to compare peak runoff before and after paving a fictional site, then sizing a detention basin's release.
Grade 10 Lesson plan
Emberton's Non-Revenue Water: Loss, Cost, and Payback
A grade 10 math lesson where students turn a fictional utility's unbilled water into a loss percent, an annual dollar figure, and a leak-program payback.
Grade 10 Lesson plan
Highgrove Plant Alum Dose: Feed Rate and Chemical Cost
A grade 10 math lesson using the pounds formula to find a fictional plant's alum feed rate in pounds per day, then its daily and yearly chemical cost.
Grade 10 Lesson plan
Wrenhaven Tiered Water Rates: Writing and Solving Bill Equations
A 50-minute grade 10 lesson where students model a fictional town's tiered water rates as equations, compute monthly bills, and solve for usage at a target bill.
Grade 11 Lesson plan
Water Operator Exam Math: Chlorine Dose and the Career Path
A grade 11 lesson pairing the certification-exam pounds formula for chlorine feed with water-sector career paths and operator wage data, set at a fictional plant.
Grade 12 Lesson plan
Draywick Road Culvert: Design Storm Risk Over 50 Years
A 60-minute grade 12 lesson building the exponential risk model for a fictional town's culvert, then sizing it with the rational method and the continuity equation.
Grade 9 Lesson plan
Delford's Two Wells: A PFAS Blending Equation Lesson
A grade 9 lesson where students write and solve a weighted-average blending equation to keep two fictional wells at or below the 4.0 ppt PFOA limit.
Grade 9 Lesson plan
Ravensford Chlorine Dosing: The Pounds Formula in Action
A 45-minute grade 9 lesson at the fictional Ravensford plant, using the pounds formula and demand-plus-residual to find a chlorine dose and daily feed rate.
Grade 9 Lesson plan
Ridgeport Pump Station: Total Dynamic Head and Pressure
A grade 9 lesson where students add static lift and friction to find total dynamic head, then convert between feet of head and psi for a fictional pump station.
Grade 9 Lesson plan
Westmere Reverse Osmosis: Modeling Recovery Rate
A 50-minute grade 9 lesson at the fictional Westmere plant, modeling reverse-osmosis recovery rate as permeate over feed and solving for a required feed flow.
Grade 11 Lesson plan
Bellwood Reservoir's Drawdown and Mussel Colony: Fitting Growth Models
A grade 11 lesson where students fit linear and exponential functions from two logged data points and solve for an unknown time value using logarithms.
Grade 12 Lesson plan
Sable Ridge Pump Station: Pipe Diameter, Velocity, and Continuity
A grade 12 lesson using the continuity equation to model how pipe diameter changes affect flow velocity at a fictional pump station upgrade.
Grade 12 Lesson plan
Desalination Recovery Rate and Salt Rejection at Talon Point
A grade 12 lesson where students calculate a fictional plant's permeate flow, salt rejection, and concentrate TDS, benchmarked against the real Carlsbad plant.
Grade 9 Lesson plan
Alder Mesa's Shrinking Aquifer: Modeling Groundwater Drawdown
A grade 9 Earth science lesson using aquifer storage change to write a linear equation projecting when a fictional town's water table hits a critical level.
Worksheets
Grade 10 Worksheet
Aldermoss Carbon Vessels: PFAS Bed Volumes and Changeout
A grade 10 worksheet where students size a fictional carbon vessel as a cylinder, find contact time and bed volumes per day, and solve for the changeout date and cost.
Grade 10 Worksheet
Corrindale Sands Desalter: Brine Load, Dilution, and Precision
A grade 10 worksheet using the pounds formula to find a fictional desalter brine strength, then solving a dilution equation and reporting at meter precision.
Grade 12 Worksheet
Windlestraw Creek Phosphorus: Allocating a Load Reduction
A grade 12 worksheet where students compute four phosphorus loads with the pounds formula, then solve for the percent reduction two sources must share.
Grade 9 Worksheet
Wickcombe's Ivyshaw Row Flush Test: Lead Against Liters Drawn
A grade 9 worksheet using a sequential flush profile from one home's lead service line to practice average rate of change and one-variable equations.
Grade 11 Worksheet
Rensford Falls Clearwell: A Chlorine CT Compliance Worksheet
A grade 11 worksheet on disinfection contact time: students size a clearwell, apply a baffling factor, compute CT achieved, and solve for a passing residual.
Grade 12 Worksheet
Calverhoe Chloramine Conversion: Feed Rate and Ratio Worksheet
A grade 12 worksheet on a fictional district switching to chloramines: feed rates in pounds per day, the chlorine to ammonia ratio, and nitrification signs.
Grade 10 Worksheet
Sedgwick Find-the-Leak Poster: Grade 10 Scale and Budget Worksheet
A grade 10 design worksheet where students plan a fictional utility's leak-awareness poster, choosing colors and solving scale, area, and print-budget problems.
Grade 11 Worksheet
The Delgado Household Water-Use Audit: Gallons and Savings
A grade 11 consumer-science worksheet where students audit a fictional household's daily water use by fixture and calculate the savings from WaterSense fixtures.
Grade 11 Worksheet
The Water Footprint of a Week's Meals: Beef and Wheat
A grade 11 consumer-science worksheet where students estimate the water footprint of a fictional week's menu using published beef and wheat water-use figures.
Grade 10 Worksheet
Greywillow Reclamation Facility: BOD Removal and Loading Worksheet
A grade 10 worksheet using the pounds formula and removal-efficiency formula on a fictional city's wastewater plant, comparing BOD and TSS to secondary limits.
Grade 10 Worksheet
Merrivale Well Blend: Meeting the 4 ppt PFAS Limit
A grade 10 worksheet on PFAS: students blend two fictional wells, size treatment removal, and write an equation to meet the 4.0 ppt federal limit.
Grade 10 Worksheet
Ochreford Utility Staffing: Operator Shifts, Licenses, and Pay
A grade 10 worksheet where students staff a fictional water plant around the clock, then compare paying overtime with hiring using national operator wage data.
Grade 9 Worksheet
Brindlemoor Pressure Zones: Elevation and PSI Worksheet
A grade 9 worksheet on the fictional Brindlemoor Water District, converting ground elevation to water pressure in psi across three streets with the 0.433 rule.
Grade 9 Worksheet
Draymoor Transmission Main: A Pipe Velocity and Flow Worksheet
A grade 9 worksheet using the continuity equation Q = A x V to find pipe velocity and flow in a fictional water district's transmission mains.
Grade 9 Worksheet
Fenwick PFAS Carbon Filter: Parts-per-Trillion Removal Worksheet
A grade 9 PFAS worksheet: students use percent removal and a linear breakthrough model to keep Fenwick's carbon filter below the parts-per-trillion limit for PFOA.
Grade 9 Worksheet
Holloway Creek Plant: Nutrient Loading and Load Limits
A grade 9 worksheet at the fictional Holloway Creek plant, using the pounds formula to find nutrient loads and solving for a concentration that meets a permit.
Grade 10 Worksheet
Redhawk Intake Channel: Flow, Velocity, and Continuity
A grade 10 hydraulics worksheet at the fictional Redhawk intake, applying Q = A x V to find flow and velocity and converting between cfs, gpm, and MGD.
Grade 12 Worksheet
Effluent Toxicity and Dilution at the Marledge Outfall
A grade 12 science worksheet on whole effluent toxicity: students find the instream waste concentration, interpolate an LC50, and convert it to toxic units.
Grade 12 Worksheet
Flood Frequency and Culvert Sizing on Tullimore Creek
A grade 12 science worksheet using 20 years of peak-flow records to rank floods, find return periods and exceedance risk, and size a replacement culvert.
Grade 9 Worksheet
Open-Channel Flow at Grantham: A Grade 9 Hydraulics Worksheet
A grade 9 hydraulics worksheet where students apply Q = A x V to an open channel, then convert flow between cubic feet per second, gpm, and MGD.
Grade 9 Worksheet
Chlorine Contact Time at Merrowfield: A Grade 9 CT Worksheet
A grade 9 worksheet where students find contact time from basin volume and flow, calculate CT for disinfection, and solve for the residual a plant needs at peak flow.
Grade 10 Worksheet
Quillfeather RO Plant: Percent Recovery and Flow Conversions
A grade 10 worksheet in which students calculate reverse osmosis percent recovery, reject flow, and gallon-to-MGD conversions for a fictional groundwater plant.
Grade 12 Worksheet
Pinehaven Distribution System: Modeling Chlorine Residual Decay
A grade 12 worksheet in which students build and use an exponential decay function for chlorine residual across a fictional town distribution system.
Math problem sets
Grade 9 Math problem set
Bramstead Utility: What a Class II License Costs and Returns
Ten grade 9 careers problems following a fictional operator-in-training through course fees, study hours, a wage step, and the months it takes to earn the cost back.
Grade 11 Math problem set
Saltmarch Ridge Irrigation: Acre-Feet and Run-Time Math
A grade 11 careers problem set in which an irrigation technician converts a net application depth to acre-feet and gallons, then solves for pivot run time and water cost.
Grade 12 Math problem set
Saxby Terrace Pressure Zone: Elevation and Tank Head Problems
A grade 12 problem set where students convert tank and street elevations into static pressures, find pressure-zone limits, and size a tank's usable storage.
Grade 9 Math problem set
Harrowmede Reservoir: A Dry-Year Water Budget in Acre-Feet
A grade 9 set where students build a dry-year water budget for a fictional reservoir, converting MGD to acre-feet and solving for the years left before dead pool.
Grade 9 Math problem set
Ostermill Orthophosphate Feed: Corrosion Control Dose Math
A grade 9 set on a fictional district adding orthophosphate after a high lead result, using the pounds formula to size the feed, the day tank, and the yearly cost.
Grade 10 Math problem set
Bellamy Lead Service Line Replacement Problem Set
A grade 10 problem set on a fictional utility's lead line replacement, modeled as a linear function with a 10-year deadline, per-line cost, and a changing action level.
Grade 10 Math problem set
Calder Ridge Reservoir and Dam: Volume, Head, and Flow Problems
A grade 10 problem set converting a fictional reservoir's acre-feet to gallons, finding pressure at a dam's turbines, and tracking powerhouse flow through unit chains.
Grade 10 Math problem set
Halden Bay Desalter: Membrane Flux and Salt Rejection
A grade 10 problem set on reverse osmosis: students find membrane flux, count elements and vessels, and compute salt rejection at a fictional brackish desalter.
Grade 11 Math problem set
Ospringe's Two Sources: pH on a Logarithmic Scale
A grade 11 problem set converting pH to hydrogen ion concentration for two fictional sources, blending them, and sizing the soda ash dose that follows.
Grade 11 Math problem set
Pentley Well Field: Drawdown, Specific Capacity, and Yield
A grade 11 problem set on a fictional well field: compute drawdown and specific capacity, solve for a safe pumping rate, and check the field against district demand.
Grade 11 Math problem set
Thornwell Dam Hydropower: Head, Flow, and Power Output Problems
A grade 11 math problem set on a small hydropower turbine: converting flow units, computing water horsepower and kilowatts, and solving for a target output.
Grade 12 Math problem set
Brindlemere Reclamation Plant: BOD Loading and Removal
A grade 12 problem set using the pounds formula to find BOD mass loading and removal efficiency at a fictional reclamation plant.
Grade 12 Math problem set
Deepwell Booster Station: Dynamic Head and Energy Cost
A grade 12 problem set computing total dynamic head, water and brake horsepower, and daily pumping energy cost for a fictional booster pump station.
Grade 12 Math problem set
Fallowfield Water Utility: Revenue and an Inclining Block Rate
A grade 12 problem set on utility finance, covering a fictional utility's revenue need with a fixed charge and a three-tier inclining block rate.
Grade 12 Math problem set
Quillbeck Solvent Plume: Darcy Velocity and Travel Time
A grade 12 problem set applying Darcy's law to a fictional spill site, finding seepage velocity, sorption-slowed plume travel time to a well, and solvent mass flux.
Grade 12 Math problem set
Trenwick Regional Water: Rate Design and Revenue Requirement
A grade 12 problem set on utility finance: revenue requirement, fixed and volumetric charges, a break-even usage, debt-service coverage, and an affordability check.
Grade 12 Math problem set
Yarrowdale Center Pivot: Irrigation Depth, Flow, and Run Hours
A grade 12 problem set sizing a fictional farm's center pivot, converting crop water need in inches to gallons, then to gpm, MGD, and cfs, and testing a well's capacity.
Grade 9 Math problem set
Caldbeck Treatment Plant: Alum Coagulant Dosing Problem Set
A grade 9 problem set using the pounds formula to size alum coagulant feed, plan bag supply, and stay within a fictional plant's pump and cost limits.
Grade 9 Math problem set
Copperton Booster Pump Station: Horsepower and Energy Cost
A grade 9 problem set that sizes a fictional booster pump in water horsepower, then works through kilowatts and daily and yearly pumping energy cost.
Grade 9 Math problem set
Kettleridge Wastewater Plant: BOD Loading and the Pounds Formula
A grade 9 problem set using the pounds formula to track BOD loading and removal at Kettleridge's wastewater plant, then writing an equation for load from concentration.
Grade 9 Math problem set
Netherford Wastewater Plant: BOD Removal and Loading Problem Set
A grade 9 problem set applying removal efficiency and the pounds formula to BOD at a fictional wastewater plant, checked against the 30 mg/L secondary standard.
Grade 9 Math problem set
Nethersby Water District: Operator Staffing and Wage Math
A grade 9 problem set on staffing a fictional utility's round-the-clock shifts, then comparing its starting wage with national operator pay and openings data.
Grade 9 Math problem set
Willowvane Constructed Wetland: Nitrogen Loading and Sizing
A grade 9 problem set on a fictional polishing wetland, using the pounds formula to find nitrogen load, removal rate, detention time, and acres needed.
Grade 10 Math problem set
Ashford Reservoir Water Budget: Acre-Feet and Days of Supply
A grade 10 problem set at the fictional Ashford Reservoir, building a drought water budget in acre-feet and solving an equation for the days until a critical low level.
Grade 10 Math problem set
Crestview Booster Pump: Horsepower, Energy, and Operating Cost
A grade 10 problem set where students chain the water-horsepower formula through efficiency to find a fictional pump station's daily energy use and cost.
Grade 11 Math problem set
Cresswick Clearwell Disinfection: Chlorine Dose and CT Math
A grade 11 problem set on chlorine demand, the pounds formula, contact time, and CT values in a fictional plant's clearwell, with equations for a required residual.
Grade 11 Math problem set
Tamsin Reservoir Drawdown: A Drought Water-Budget Set
A grade 11 problem set on a fictional reservoir's drought drawdown, converting MGD to acre-feet and solving a linear storage equation for the days to an emergency level.
Grade 12 Math problem set
Highmarsh Reservoir Water Budget and Days of Supply
A grade 12 science problem set on a fictional reservoir: students move between acre-feet, gallons, and MGD to find net drawdown and how many days of supply remain.
Grade 9 Math problem set
Pump Station Horsepower at Haldane: A Grade 9 Energy Problem Set
A grade 9 problem set where students find water horsepower, brake horsepower, motor power, and the daily energy cost of a fictional high-service pump station.
Grade 9 Math problem set
Pinehaven Well: Drawdown, Specific Capacity, and Safe Yield
A grade 9 problem set where students use a fictional town well's water levels to find drawdown and specific capacity, then set up equations for safe pumping yield.
Grade 9 Math problem set
Birch Hollow Pump Station: Head, Pressure, and Flow Problems
A grade 9 engineering problem set on a booster pump station: students find total dynamic head, discharge pressure, flow conversions, and tank fill time.
Grade 9 Math problem set
Marsh Landing Seawater Reverse Osmosis: Recovery and Flux
A grade 9 engineering set on a seawater reverse osmosis plant: students find permeate and concentrate flows, membrane flux, a concentration factor, and daily energy.
Grade 10 Math problem set
Redwing Filtration Plant: Filter Loading and Turbidity Removal
An 8-problem grade 10 set where students calculate filter loading rate and turbidity removal efficiency, checking results against real EPA compliance limits.
Grade 12 Math problem set
Sterling Hollow Chlorine Dosing: Operator-Certification Math
A grade 12 problem set chaining the pounds formula and the percent-to-mg/L conversion to size a hypochlorite feed pump at a fictional treatment plant.
Grade 12 Math problem set
Thornfield Wastewater Plant: BOD Removal and Exponential Decay
A grade 12 problem set applying percent removal and exponential decay functions to BOD data from a fictional wastewater treatment plant.
Grade 9 Math problem set
Crestline Reservoir's Drought Drawdown: Equations and Rationing Limits
A grade 9 problem set where students write and solve one-variable equations for a drought-stricken reservoir's drawdown and a household's rationing constraints.
Grade 9 Math problem set
Quill Lake's Algal Bloom: Exponential Growth and Linear Cleanup
A grade 9 math problem set modeling a fictional lake's algal bloom, contrasting exponential growth before treatment with linear decline after treatment starts.
Grade 9 Math problem set
Larkspur Flats Well Drawdown: A Grade 9 Linear Equations Problem Set
Eight algebra problems that model a subdivision's groundwater well as a linear equation, using drawdown rate, a safety shutoff, and unit conversions.
Classroom activities
Grade 9 Classroom activity
Sallowfield Farms Soil Moisture Rounds: A Six-Week Pivot Game
A grade 9 activity where teams run a fictional center-pivot field through six weekly rounds, holding stored soil water inside a band while applying as little as possible.
Grade 11 Classroom activity
Fix-a-Leak Station Rotation: Ranking Household Water Waste
A grade 11 station-rotation activity where teams calculate and rank the yearly water wasted by four fictional household leaks and choose the top fix.
Grade 9 Classroom activity
Reduce Lead at the Tap: A Grade 9 Home-Action Station Rotation
A grade 9 station rotation where students compare tap-lead readings, flush-water use, and filter costs to rank home actions against the lead action level.
Grade 10 Classroom activity
Briarcliff Creek PFAS Spill: A Contamination Response Relay
A grade 10 station-rotation activity where teams calculate dilution, travel time, and treatment effectiveness for a fictional PFAS spill nearing a water intake.
Projects
Grade 12 Project
Quarryhill Water Works: Non-Revenue Water Audit and Plan
A grade 12 four-session project where teams audit a fictional utility's water losses, value them, and propose a loss-reduction plan within a fixed budget.
Quizzes & test questions
Grade 9 Quiz & test questions
Whelkmere Water Works: A Distribution Operator Skills Quiz
A 40-point grade 9 careers quiz on the distribution operator's job at a fictional hillside utility, mixing role questions with pressure, flow, and storage math.
Grade 10 Quiz & test questions
Vessenden Instrument Technician: Calibration and Signal Scaling
A grade 10 careers quiz on the water plant instrumentation technician role, covering calibration, 4-20 mA signal scaling, percent error, and alarm setpoints.
Grade 12 Quiz & test questions
Ashenholt Digester: Biosolids Loading and Energy Recovery Exam
A grade 12 exam on anaerobic digestion at a fictional facility, from solids loading and volatile solids destruction to biogas, electricity, and detention time.
Grade 11 Quiz & test questions
Coalport Plant Process Math: A Grade 11 Treatment Unit Test
A 45-minute, 30-point grade 11 unit test mixing multiple-choice, short-answer, and computation items on treatment process math for a fictional plant.
Grade 12 Quiz & test questions
Cranmoor Water District Finance and Infrastructure Test
A grade 12 unit test on water infrastructure and utility finance, mixing recall of real US figures with cost math for a fictional water district.
Grade 9 Quiz & test questions
Kestrel Bend Water Plant: A Grade 9 Treatment Math Quiz
A 30-point grade 9 quiz mixing multiple-choice, short-answer, and computation items on dosing, detention time, removal efficiency, and pressure at a fictional plant.
Grade 9 Quiz & test questions
Varmoor Utility Operations Math: A Grade 9 Unit Test
A grade 9 unit test on the fictional Varmoor utility, mixing multiple-choice, short-answer, and computation items on the pounds formula, flow conversions, and pressure.