10 free, exam-style Professional Engineer Civil Water Resources and Environmental (PE Civil WRE) practice questions with answers and explanations. No signup required. Work through them below, then take the full free PE Civil WRE practice test to study every exam domain.
These 10 free PE Civil WRE questions are organized by exam domain, so you can see how each part of the Professional Engineer Civil Water Resources and Environmental blueprint is tested. Reveal the answer and explanation under each question.
A centrifugal pump delivers 1,200 gpm against a total dynamic head of 95 ft. If the pump efficiency is 82% and the motor efficiency is 93%, the required motor input horsepower is most nearly:
Correct answer: C - 38 hp
A centrifugal pump operates at 1,750 rpm, delivering 900 gpm at 80 ft of total dynamic head. A variable frequency drive increases the speed to 2,100 rpm. According to the affinity laws, the head developed by the pump at the new speed is most nearly:
Correct answer: C - 115 ft
A trapezoidal open channel has a bottom width of 8 ft, side slopes of 2H:1V, a Manning's roughness coefficient of 0.025, and a longitudinal slope of 0.004 ft/ft. If the normal depth of flow is 2.0 ft, the channel discharge under uniform flow conditions is most nearly:
Correct answer: D - 114 cfs
A 120-acre watershed consists of 45 acres of commercial development (C = 0.85), 50 acres of residential lots (C = 0.40), and 25 acres of open parkland (C = 0.15). Using the Rational Method with a 10-year rainfall intensity of 3.6 in/hr at the time of concentration, the peak runoff rate is most nearly:
Correct answer: C - 223 cfs
A confined aquifer with transmissivity T = 25,000 gpd/ft and storativity S = 2.0 × 10⁻⁴ is pumped at a constant rate of 200 gpm. Using the Cooper-Jacob approximation, the drawdown at an observation well 500 ft from the pumping well after 2 days of continuous pumping is most nearly:
Correct answer: D - 5.2 ft
A treated wastewater effluent (Q = 3.0 MGD, DO = 2.0 mg/L) discharges into a stream (Q = 45 cfs, DO = 8.5 mg/L). Assuming complete and instantaneous mixing, and using a conversion of 1 MGD = 1.547 cfs, the dissolved oxygen concentration immediately downstream of the discharge is most nearly:
Correct answer: B - 7.9 mg/L
A chlorine contact chamber at a water treatment plant has a theoretical hydraulic detention time of 45 minutes and a baffling factor of 0.5. The free chlorine residual measured at the outlet is 0.8 mg/L. The effective CT value achieved is most nearly:
Correct answer: A - 18 mg·min/L
An activated sludge aeration basin has a volume of 1.5 MG and receives an influent flow of 6.0 MGD with a BOD concentration of 180 mg/L. The mixed liquor volatile suspended solids concentration is maintained at 2,400 mg/L. The food-to-microorganism (F:M) ratio is most nearly:
Correct answer: B - 0.30 day⁻¹
A construction project requires a trench excavation to a depth of 14 ft in Type B soil. No shoring system will be used. According to OSHA 29 CFR 1926 Subpart P, the maximum allowable cut slope for the excavation walls is:
Correct answer: A - 1 horizontal to 1 vertical (45°)
A proposed construction site has the following Universal Soil Loss Equation (USLE) parameters: R = 250, K = 0.28, LS = 2.0, and P = 1.0. After grading exposes bare soil (C = 1.0), erosion control blankets are installed, reducing C to 0.08. The estimated soil loss with the blankets in place is most nearly:
Correct answer: B - 11.2 tons/acre/year
The PE Civil WRE exam also covers these domains. Drill them in the full free practice test:
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