CWD Atypical Situations & Problem Wetlands Flashcards

What is the purpose of the Wetland Determination Data Form when resolving atypical situations?

Answer: To document all field evidence supporting wetland or non-wetland determinations

The Wetland Determination Data Form systematically records vegetation, soil, and hydrology data, providing a defensible documented basis for the delineation decision.

When standard field indicators are absent, which soil feature provides the most reliable evidence of historical wetland conditions?

Answer: Redoximorphic features such as mottles and iron concentrations

Redoximorphic features including mottles, iron concentrations, and depleted matrices form under anaerobic conditions and persist long after drainage, indicating historical wetland hydrology.

What approach should be used when a delineator suspects atypical conditions due to drought?

Answer: Install monitoring wells, assess soil indicators, and note drought conditions on the data form

During drought years, delineators should note climatic conditions on data forms, rely on persistent soil indicators, and consider monitoring wells to capture seasonal hydrology patterns.

Which agency guidance document supplements the 1987 Manual for difficult delineation decisions in specific regions?

Answer: Corps of Engineers Regional Supplements to the 1987 Wetland Delineation Manual

Corps Regional Supplements provide updated, region-specific indicators and guidance to supplement the 1987 Manual for complex and atypical delineation situations.

What is the significance of the ordinary high water mark (OHWM) in atypical delineation situations?

Answer: It defines the lateral extent of Corps jurisdiction for non-wetland waters such as rivers and streams

The OHWM defines jurisdiction over non-wetland waters of the U.S. (rivers, streams, lakes) and is determined separately from the three-parameter wetland delineation method.

Which scenario best describes a difficult delineation involving prior converted cropland (PC)?

Answer: Agricultural land drained and farmed before 1985 that may be exempt from Section 404 jurisdiction

Prior converted cropland refers to areas drained or manipulated for farming before December 23, 1985, and is generally exempt from Section 404 wetland jurisdiction under the Food Security Act.