Water Resources HubFree FE Civil exam prep and PE Civil exam prep
Thirty-four guided modules — 18 water-resources topics plus all 16 FE Civil sections — covering every FE Civil exam topic — water resources, structures, geotechnics, transportation, and the rest — plus PE Civil (Water Resources & Environmental) depth. Formulas are defined, worked examples show every step, and free civil engineering exam practice questions with solutions check your understanding. Mapped to the current NCEES FE Civil and PE Civil: Water Resources and Environmental specifications.
How this works
Learn the theory — free
Start with the blue FE foundation material, then move into the amber PE-depth sections for design judgement, multi-step analysis, and system behaviour.
Watch for the traps
Every topic identifies unit traps, modelling assumptions, and the point where an FE calculation becomes a PE design or interpretation question.
Try a full exam simulation — paid
When the theory feels solid, step up from the free topic tasters to a full timed exam simulation with worked solutions.
Current NCEES exam blueprint
This hub follows the official topic names and question ranges currently published by NCEES. The FE Civil specification is effective July 2020. The PE Civil: Water Resources and Environmental specification is effective April 2024 and applies before April 2027.
Water-related FE areas
- Fluid Mechanics 4–6 questions
- Hydraulics and Hydrologic Systems 8–12
- Environmental Engineering 6–9
Expect concise handbook-based calculations across a 110-question breadth exam.
Discipline-specific PE areas
- Hydraulics—Closed Conduit 7–11
- Hydraulics—Open Channel 7–11
- Hydrology 8–12
- Groundwater and Wells 4–6
- Surface Water and Groundwater Quality 5–8
- Drinking Water Distribution and Treatment 6–9
- Wastewater Collection and Treatment 7–11
The April 2024 PE exam has no common breadth block: all 80 questions are WRE-specific. Analysis and Design, Project Planning, Soil Mechanics, Materials, and Project Sitework are also tested; Project Sitework carries 9–14 questions.
Official specifications: FE Civil (effective July 2020) · PE Civil: WRE (effective April 2024, before April 2027). Always check the NCEES site for later revisions.
Eighteen water-focused learning modules
Fluid Properties & Hydrostatics
Fluid properties, pressure, hydrostatic forces, and the fluid-mechanics assumptions that support both exams.
Topic 2Buoyancy & Flotation
Archimedes’ principle and stability — core fluid-statics reasoning before closed-conduit analysis.
Topic 3Continuity, Energy & Momentum
Continuity, Bernoulli, momentum, flow measurement, and control-volume reasoning.
Topic 4Pipe Flow
Darcy-Weisbach, Hazen-Williams, minor losses, pipe networks, force mains, and wet wells.
Topic 5Pumps & System Curves
Operating point, affinity laws, power, NPSH, distribution demand, storage, and pump operation.
Topic 6Open-Channel Flow
Manning flow, critical depth, hydraulic jumps, culvert control, and stormwater conveyance.
Topic 7Hydrology & Runoff
IDF interpretation, Rational and NRCS runoff, hydrographs, detention, and reservoir routing.
Topic 8Groundwater Flow
Darcy flow, aquifers, steady and transient well drawdown, and contaminant travel velocity.
Topic 9Water Treatment
Mass balance, quality indicators, distribution, coagulation, sedimentation, filtration, and disinfection.
Topic 10Wastewater Treatment
Collection hydraulics, I/I, BOD, activated sludge, nutrients, solids, and clarifier loading.
Topic 11Water Hammer & Surge
Wave celerity, the Joukowsky pressure rise, critical closure time, and surge-control devices.
Topic 12Pipe Networks
Equivalent pipes, series and parallel systems, and the Hardy Cross loop method.
Topic 13Culverts & Spillways
Inlet vs outlet control, weir flow, spillway basics, and tailwater effects.
Topic 14Stormwater Management & BMPs
Detention and retention sizing, outlet structures, first flush, and LID concepts.
Topic 15Water Distribution Systems
Demands and peaking factors, storage sizing, pressure zones, and network analysis concepts.
Topic 16Wastewater Collection Systems
Gravity sewer design with Manning's, self-cleansing velocity, lift stations, and infiltration & inflow.
Topic 17Sedimentation & Erosion
The USLE, sediment transport basics, settling-basin overflow rates, and channel protection.
Topic 18Flood Frequency & Reservoirs
Return period and risk, Log-Pearson III concepts, reservoir yield, and flood routing.
In a hurry? The formula quick-reference index collects every key equation from all eighteen water topics and sixteen FE Civil sections on one page, each with its variables defined.
Sixteen FE Civil exam sections
Beyond water: the rest of the FE Civil specification — mathematics, mechanics, structures, geotechnics, transportation, construction, surveying, and environmental engineering. Every section includes free theory, a five-question mini-quiz with worked solutions, and its key equations in the formula index.
Mathematics
Calculus, differential equations, matrices, vectors, complex numbers, and numerical methods — the engine room of the FE exam.
FE CivilProbability & Statistics
Probability laws and counting, binomial and normal distributions, mean and variance, confidence intervals, and regression basics.
FE CivilComputational Tools
Spreadsheet logic and functions, algorithms and flowcharts, error types and propagation, and numerical-methods concepts.
FE CivilEthics & Professional Practice
NCEES code of ethics, responsible charge and sealing rules, conflicts of interest, liability, and contract basics.
FE CivilEngineering Economics
Time value of money, interest factors, NPV, IRR, benefit-cost, breakeven, depreciation, and inflation.
FE CivilStatics
Force resultants, equilibrium, trusses, centroids, moments of inertia, distributed loads, and friction — the 9–14 question statics core of the FE Civil exam.
` in the topics grid (the one linking `wastewater-treatment.html`), before the grid's closing `Dynamics
Rectilinear and curvilinear kinematics, Newton's second law, work–energy, impulse–momentum, and vibration basics.
FE CivilMechanics of Materials
Axial stress and strain, torsion, beam bending and shear, combined loading, Mohr's circle, deflection, and Euler buckling.
FE CivilMaterials
Stress–strain curves, steel vs concrete vs timber vs asphalt, materials testing concepts, and concrete fundamentals (w/c ratio, curing).
FE CivilStructural Analysis
Determinacy and stability, reactions, shear and moment diagrams, influence lines, approximate indeterminate analysis, and beam deflections.
FE CivilStructural Design
ASCE 7 load combinations, steel tension members, columns, and beams, reinforced-concrete flexure and shear, one-way slabs, and timber basics.
FE CivilGeotechnical Engineering
Phase relations, effective stress, seepage, consolidation, shear strength, earth pressure, bearing capacity, and slope stability — the joint-largest FE Civil section.
FE CivilTransportation Engineering
Stopping sight distance, horizontal and vertical curves, traffic flow and level of service, signal timing, ESALs, and the structural number.
FE CivilConstruction Engineering
CPM scheduling and float, Gantt charts, quantity takeoff, equipment productivity, earthwork volumes, and cost-control concepts.
FE CivilSurveying
Differential leveling, tape corrections, bearings and azimuths, traverse closure with the compass rule, area by coordinates, and contour concepts.
FE CivilEnvironmental Engineering
Mass balance, the Streeter-Phelps oxygen sag, water quality parameters, air quality, solid waste, and noise — the FE Civil environmental breadth.
Free interactive calculators
Check your hand calculations against these browser-based tools — no account, no download. Each one shows the governing equation so you can see exactly what it is doing.
⚡ Quick Engineering Checks
40 plug-in calculators for working engineers — rebar weight, concrete volume and mix, beam reactions, bearing capacity, hydraulics, earthworks, unit conversions. Enter a few numbers, get an instant answer with the formula shown.
Manning's Equation
Open-channel discharge for rectangular, trapezoidal, and full circular sections — SI and US units.
CalculatorHazen-Williams Head Loss
Velocity, discharge, and friction loss for water pipes from diameter, C-factor, and slope.
CalculatorRational Method Runoff
Peak runoff rate from runoff coefficient, rainfall intensity, and drainage area.
CalculatorPump Operating Point
Where the pump curve meets the system curve — solve for flow and head with an adjustable sample pump.
CalculatorWater Hammer Surge
Wave celerity, Joukowsky pressure rise, and rapid vs gradual valve-closure classification.
CalculatorGravity Sewer Capacity
Partial-full Manning's capacity for circular sewers with self-cleansing and d/D design checks.
CalculatorUSLE Soil Loss
Annual soil loss from rainfall, soil, topography, cover, and practice factors.
CalculatorReservoir Yield & Storage
Required storage from monthly inflows and demands via the Rippl mass-curve method.
CalculatorEngineering Economics
All eight interest factors, nominal-to-effective rate conversion, and NPV of a cash-flow series.
CalculatorDynamics
Projectile trajectory and mass–spring vibration — range, height, flight time, natural frequency, and damped frequency in SI or US units.
CalculatorShear & Moment
Reactions, shear, and moment for a simply supported beam with up to two point loads and a uniform load — SI and US units.
CalculatorBearing Capacity & Phase Relations
Terzaghi qult for strip, square, and circular footings, plus a three-phase soil solver — SI and US units.
CalculatorVertical Curve
High/low point station and elevation, elevation at any station, K value, and PVI/PVT from grades, curve length, and PVC data.
CalculatorEarthwork Volume
Average end area and prismoidal volumes from station cross-section areas, in cubic yards, with swell conversion.
CalculatorTraverse Closure
Latitudes and departures, linear misclosure and precision, compass-rule adjusted coordinates, and area by the coordinate method.
Take these formulas with you — free
The essential water resources equations from this page, condensed into a 2-page printable cheat sheet. Free — just enter your email to download.
Ready for the full rehearsal?
$24 per full simulation
The FE Civil Exam Simulation is a 110-question timed simulation covering every FE Civil section — water resources included — with detailed worked solutions for every question. PE Civil (Water Resources & Environmental) simulations available too. Here is the flavour of one water-resources question:
Sample question Open-channel flow
A rectangular concrete channel 2.0 m wide carries a normal depth of 0.80 m on a bed slope of 0.001. Take Manning's n = 0.013. The discharge is closest to:
- 1.4 m³/s
- 2.3 m³/s
- 3.1 m³/s
- 4.0 m³/s
Answer: B. A = 1.60 m², P = 3.60 m, R = 0.444 m. V = (1/0.013)(0.444)2/3(0.001)1/2 = 1.42 m/s, so Q = VA ≈ 2.27 m³/s.
109 more questions like it — fluids, hydraulics, hydrology, groundwater, treatment, and every other FE Civil section — each with a full step-by-step solution.
Two paths through the same water
The FE and the PE both test water resources, but they test different kinds of thinking. This site serves both, and it is honest about the difference:
Breadth and fluency
Identify the equation → find the variables → calculate → select the answer. The free theory modules, formula index, calculators, and the five core mini-quiz questions plus two Bridge Challenges on each topic page build exactly this fluency.
Depth and judgment
Interpret the scenario → determine the governing approach → choose your assumptions → work through multiple steps → check the result for reasonableness → make a design decision. Each topic quiz now ends with two Bridge Challenge questions at this level — try them free, with full worked solutions.
For the full PE-depth route, the FE→PE Bridge Pack takes every water topic through a four-level ladder — FE, FE+, PE, PE+ — so you climb from one-step calculations to system-level engineering judgment instead of jumping straight into the deep end.
Frequently asked questions
What is the difference between the FE Civil and PE Civil water-resources topics?
The FE Civil exam is a breadth exam: water appears in three of its seventeen areas — Fluid Mechanics (4–6 questions), Hydraulics and Hydrologic Systems (8–12), and Environmental Engineering (6–9). The PE Civil: Water Resources and Environmental exam is a depth exam with no breadth block since April 2024: eight of its twelve areas are water-specific (closed-conduit and open-channel hydraulics, hydrology, groundwater, water quality, drinking water, wastewater), at professional analysis-and-design depth.
How should I use this site to study?
Work through the thirty-four theory modules in order — each builds on the last. Use the formula index for revision, the free mini-quizzes on each topic page to check understanding, and the calculators to verify your hand calculations. When the theory feels solid, move to timed exam simulations under exam conditions.
What is free and what is paid?
All theory modules, the formula index, the calculators, and the topic mini-quizzes are free — no account needed. The paid products are full-length timed practice exams and quizzes with detailed worked solutions, sold through our Gumroad store.
Which NCEES specifications does the site follow?
The FE Civil specification effective July 2020 (still the current version) and the PE Civil: Water Resources and Environmental specification effective April 2024 — the version NCEES lists as applying before April 2027. Specifications change, so always confirm against the current documents on ncees.org.
Can I use the calculators instead of hand calculations on the exam?
No — the calculators are study and checking tools. On the exam you will work by hand with the NCEES reference handbook, so practise the manual methods here and use the calculators to confirm your arithmetic and build intuition for how each variable affects the answer.
Is this site affiliated with NCEES?
No. Water Resources Hub is an independent study aid. It is not affiliated with, sponsored by, or endorsed by NCEES, and it is not a substitute for professional engineering judgement.
Who runs Water Resources Hub?
Water Resources Hub is an independent study resource — see the About page for more.
What is a Bridge Challenge question?
Each topic quiz now ends with two Bridge Challenge questions pitched at PE depth: multi-step problems that require method selection, unit conversions, and interpretation of the result — for example, sizing detention storage from a time-of-concentration → IDF → Rational-method chain, or judging a pump selection against NPSH. They are free, with full worked solutions, and they preview the difficulty ladder used in the FE→PE Bridge Pack.
How is PE problem-solving different from FE problem-solving?
FE problems are usually: identify the equation, substitute, calculate, select. PE problems add layers: interpret the scenario, determine which method governs, choose reasonable assumptions, chain two to four calculations, sanity-check the answer, and often make a design decision (which criterion controls? which option do you select?). The site's FE path builds fluency; the Bridge Challenges and the Bridge Pack build the judgment layer on top.
I'm only taking the FE. Do I need the PE-level material?
No. The core theory, formula index, calculators, and the five standard quiz questions per topic cover FE water topics well on their own. The Bridge Challenges are optional stretch problems — skip them guilt-free if the FE is your target, or use them as a confidence check once the standard questions feel easy.
Who this is for
FE Civil candidates: use Topics 1–3 as Fluid Mechanics foundations, then study the FE-level portions of Topics 4–14 for Hydraulics and Hydrologic Systems — including the new modules on water hammer, pipe networks, culverts and spillways, and stormwater management — plus the water-relevant portions of the Environmental Engineering material.
PE Civil: Water Resources and Environmental candidates: concentrate on the amber PE-depth sections. The modules use the current NCEES area names and extend the FE equations into networks, routing, collection, treatment, and design interpretation.
This water-focused hub does not replace preparation for the PE areas Project Planning, Soil Mechanics, Materials, Analysis and Design, and Project Sitework. Formulas state units and assumptions plainly; candidates should verify all procedures against the reference handbook and design standards supplied for their exam appointment.
Get a daily FE/PE problem on Telegram
One exam-style water resources problem every day, with worked solutions and discussion alongside other candidates — free.