Practice Test Geeks(CFS) Certified Floodplain Surveyor Practice Test
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Surveying Techniques & Data Documentation Flashcards

7 cards from real CFS 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. For a FEMA LOMA application, what minimum survey accuracy is required for the elevation of the lowest adjacent grade?

    Answer: ±0.5 foot

    FEMA requires LAG and lowest floor elevations on LOMA applications to be accurate to within ±0.5 foot of the true elevation.

  2. A Manning's n roughness coefficient is assigned to each portion of a cross-section in HEC-RAS. Which field observation helps determine appropriate n values for a natural channel?

    Answer: Bed material size, vegetation density, channel irregularity, and degree of meandering

    Manning's n is determined by evaluating bed material size (grain roughness), vegetation density, channel irregularity, obstructions, and degree of meandering.

  3. What does 'freeboard' refer to in the context of floodplain surveying and levee certification?

    Answer: The vertical distance between the water surface at the base flood and the top of the levee

    Freeboard is the vertical safety margin between the base flood water surface elevation and the top of a levee or flood control structure.

  4. When performing a GPS RTK survey for vertical control in a floodplain study, which factor most affects the accuracy of the results?

    Answer: The quality of the geoid model used and number of satellites in view

    RTK vertical accuracy depends critically on the geoid model quality (to convert ellipsoid to orthometric heights) and the satellite geometry and count.

  5. A surveyor is documenting a culvert for inclusion in a flood study. Which dimension is most critical for hydraulic analysis?

    Answer: The inlet invert elevation, outlet invert elevation, shape, size, and length

    Hydraulic analysis of a culvert requires the inlet and outlet invert elevations, cross-sectional shape and dimensions, and length to compute headwater and tailwater relationships.

  6. In the context of FEMA flood studies, what is the purpose of a 'split flow' analysis?

    Answer: To account for floodwater that leaves the main channel and travels through a separate flow path away from the primary channel

    Split flow analysis models situations where floodwater overtops a natural or artificial divide and travels a separate path, bypassing part of the main channel reach.

  7. Which survey method is most appropriate for rapidly collecting dense elevation data over a large, inaccessible floodplain with vegetative cover?

    Answer: Airborne LiDAR with full-waveform processing to improve ground detection under vegetation

    Airborne LiDAR with full-waveform processing maximizes ground returns through vegetation, making it the best option for large, inaccessible vegetated floodplains.