Practice Test Geeks(CPESC) Certified Professional in Erosion and Sediment Control Practice Test
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Hydrology & Hydraulics Flashcards

7 cards from real CPESC practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

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  1. Which hydrologic method is most commonly used to estimate peak runoff rates from small urban and agricultural watersheds for erosion and sediment control design?

    Answer: Rational Method (Q = CiA)

    The Rational Method (Q = CiA) is the most widely used approach for estimating peak runoff from small watersheds, making it standard for erosion and sediment control sizing.

  2. In the Rational Method formula Q = CiA, what does the variable 'C' represent?

    Answer: Runoff coefficient reflecting land cover and soil type

    The runoff coefficient 'C' represents the fraction of rainfall that becomes surface runoff, varying by land use, soil type, and slope.

  3. Time of concentration (Tc) in hydrology is defined as:

    Answer: The time for runoff to travel from the hydraulically most remote point to the outlet

    Time of concentration is the time it takes for water to travel from the farthest point of the watershed to the design point, which determines the peak runoff rate.

  4. Which NRCS (SCS) Hydrologic Soil Group has the highest runoff potential and lowest infiltration rate?

    Answer: Group D

    Hydrologic Soil Group D soils (clays, shallow soils) have very low infiltration rates and produce the highest runoff, making them critical to identify for erosion risk.

  5. Manning's equation is primarily used in erosion and sediment control to:

    Answer: Estimate flow velocity and discharge in open channels and swales

    Manning's equation (Q = (1/n)AR^(2/3)S^(1/2)) is the standard formula for computing flow velocity and discharge in open channels, ditches, and vegetated swales.

  6. A watershed with a high SCS Curve Number (CN) value indicates:

    Answer: Low infiltration and high runoff potential

    High CN values (near 100) indicate little infiltration and high runoff potential, typically associated with impervious surfaces or saturated soils.

  7. For a construction site, which factor most significantly increases peak runoff compared to pre-construction conditions?

    Answer: Removal of topsoil and vegetation reducing infiltration

    Removing vegetation and topsoil eliminates infiltration capacity, dramatically increasing imperviousness and peak runoff rates during construction.

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Sources & references

Exam facts on this page (fees, format, dates, passing scores) are checked against these official sources; the date is our last check. Editorial policy

  1. envirocert.org — Registration deadline, score validity, fees, renewal, retake fee, passing score, exam information · verified Oct 2026
  2. envirocertintl.org — Eligibility, score release, time limit, test delivery, fees, renewal · verified Oct 2026