CWD Hydrology & Soils 2

Question 1

Which soil horizon is most likely to exhibit redoximorphic features in a seasonally saturated wetland?

Accepted Answer

B horizon

Answer

The B horizon typically shows redoximorphic features because it experiences prolonged saturation and reducing conditions during wet seasons.

Question 2

What is the primary mechanism by which iron concentrations (mottles) form in wetland soils?

Accepted Answer

Oxidation of ferrous iron upon re-aeration

Answer

Iron concentrations form when ferrous iron (Fe2+), mobilized under anaerobic conditions, is oxidized to ferric iron (Fe3+) and precipitates upon re-aeration.

Question 3

A wetland site shows a water table consistently at 15 cm below the surface for 8 consecutive weeks during the growing season. Does this meet the USACE inundation/saturation threshold for wetland hydrology?

Accepted Answer

Yes, because saturation within 30 cm for 14+ consecutive days during the growing season qualifies

Answer

The USACE threshold requires saturation within 30 cm of the surface for 14 or more consecutive days during the growing season.

Question 4

Which of the following is a primary indicator of wetland hydrology under the 1987 USACE Wetland Delineation Manual?

Accepted Answer

Recorded inundation or saturation data from a staff gauge or well

Answer

Recorded inundation or saturation data from a staff gauge or monitoring well is a primary hydrologic indicator under the 1987 manual.

Question 5

What does a gleyed soil matrix (low chroma, bluish-gray color) indicate about soil conditions?

Accepted Answer

Prolonged anaerobic reducing conditions causing iron reduction

Answer

A gleyed matrix results from prolonged anaerobic conditions where iron is reduced to its ferrous form, producing bluish-gray or greenish-gray colors.

(CWD) Certified Wetland Delineator Practice Test

(CWD) Certified Wetland Delineator Practice Test

CWD Hydrology & Soils 2