CWD Wetland Identification & Classification 3 — Questions and Answers
Question 1: In the Cowardin classification, which water regime modifier is used for areas that are flooded throughout the year in all years?
- Intermittently exposed
- Permanently flooded (Correct answer)
- Subtidal
- Semipermanently flooded
Correct answer: Permanently flooded
Permanently flooded means water covers the land surface throughout the year in all years.
Question 2: Which HGM subclass describes a wetland located on a slope where groundwater discharges to the surface and flows downslope as sheet flow?
- Depressional
- Slope (Correct answer)
- Flats
- Lacustrine fringe
Correct answer: Slope
Slope wetlands occur on topographic inclines and are fed by groundwater discharge, with lateral water movement as their primary hydrologic characteristic.
Question 3: A delineator finds black, mucky soil with a strong sulfurous odor in the upper 12 inches. This is most indicative of:
- A naturally drained upland with organic matter
- A hydric soil with reduced conditions and hydrogen sulfide production (Correct answer)
- A non-hydric mineral soil with high organic carbon
- A disturbed site with petroleum contamination
Correct answer: A hydric soil with reduced conditions and hydrogen sulfide production
Hydrogen sulfide odor (rotten egg smell) indicates strongly anaerobic reducing conditions characteristic of hydric soils.
Question 4: Which indicator is used to confirm wetland hydrology in areas where surface water is not present at the time of observation?
- Presence of OBL plant species only
- Secondary indicators such as water-stained leaves or drift deposits (Correct answer)
- Soil drainage class alone
- USDA SSURGO map data only
Correct answer: Secondary indicators such as water-stained leaves or drift deposits
Secondary hydrologic indicators like drift lines, water-stained leaves, sediment deposits, and aquatic invertebrates confirm past inundation when water is not present.
Question 5: According to the 1987 Corps Manual, what percentage of dominant plant species must be hydrophytic (OBL, FACW, FAC) to meet the vegetation criterion?
- More than 25%
- More than 50% (Correct answer)
- More than 75%
- 100%
Correct answer: More than 50%
More than 50% of dominant species across all strata must have a wetland indicator status of OBL, FACW, or FAC to meet the hydrophytic vegetation criterion.
Question 6: A Type 4 wetland in the Circular 39 (Shaw & Fredine) classification is described as:
- Inland fresh meadow
- Inland shallow fresh marsh
- Inland deep fresh marsh (Correct answer)
- Inland open fresh water
Correct answer: Inland deep fresh marsh
Type 4 in Circular 39 is Inland Deep Fresh Marsh, with water typically 6 inches to 3 feet deep supporting emergents like cattail and bulrush.
Question 7: When using the FAC-neutral test to determine if vegetation is hydrophytic, which species are excluded from the calculation?
- OBL species only
- FAC species only (Correct answer)
- FACU and UPL species only
- Both FACU and UPL species, and FAC species are excluded
Correct answer: FAC species only
The FAC-neutral test excludes FAC species and evaluates whether the remaining dominants are predominantly hydrophytic (OBL and FACW vs. FACU and UPL).
CWD Wetland Identification & Classification 3
In the Cowardin classification, which water regime modifier is used for areas that are flooded throughout the year in all years?