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.
Read the first 7 Surveying Techniques & Data Documentation flashcards as text
A floodplain surveyor identifies a discrepancy between field-measured ground elevations and the existing FIRM. What is the correct next step?
Answer: Document the discrepancy thoroughly and initiate a map amendment or revision process if warranted
Discrepancies between field data and the FIRM must be thoroughly documented, and if significant, a LOMA, LOMR-F, or LOMR should be submitted to correct the map.
When surveying a floodway encroachment boundary, what hydraulic condition defines the floodway limit?
Answer: The channel and adjacent floodplain area needed to convey the base flood discharge while limiting surcharge to 1 foot above the natural flood profile
The regulatory floodway is the channel plus adjacent floodplain needed to pass the 1% annual chance flood with no more than a 1-foot increase in water surface elevation (surcharge).
What is the correct procedure for establishing a temporary benchmark (TBM) in the field for a flood elevation survey?
Answer: Set a nail or spike in a stable, permanent object, reference it to a published NAVD 88 benchmark via differential leveling, and document its location and description
A TBM must be physically set in a stable object, tied to a published NAVD 88 benchmark through differential leveling, and fully documented for future reference.
During a flood study, a surveyor collects water surface elevation data during a high-water event. What documentation should accompany the high-water mark (HWM) data?
Answer: The elevation, location coordinates, quality rating (excellent/good/fair/poor), type of mark (seed line, stain, debris), and date observed
High-water mark documentation must include elevation, GPS coordinates, quality rating, mark type description, and date to allow proper use in hydraulic model calibration.
A surveyor is asked to determine the 'effective model' cross-section data versus 'revised' cross-section data in a LOMR submittal. What does 'effective' data refer to?
Answer: The cross-section geometry currently used in the adopted FEMA hydraulic model on the effective FIRM
Effective data refers to the cross-section geometry in the currently adopted FEMA hydraulic model that produced the water surface elevations shown on the effective FIRM.
Which condition would require a surveyor to perform a bathymetric survey as part of a flood study?
Answer: When significant portions of the channel cross-section are below the water surface and cannot be measured by conventional land surveying methods
Bathymetric surveys using echo sounders or multibeam sonar are needed when the channel bed lies below the water surface and conventional rod-and-level methods cannot reach the bottom.
In preparing a Flood Insurance Study (FIS) report, which table documents the water surface elevations at specific locations for the 10%, 4%, 2%, 1%, and 0.2% annual chance floods?
Answer: The Floodway Data Table
The Floodway Data Table in the FIS report presents water surface elevations and floodway widths at cross-section locations for multiple flood frequencies including the regulatory 1% annual chance event.