Wetland Delineation
Definition
Wetland delineation identifies boundaries of wetlands based on hydrology, hydric soils, and hydrophytic vegetation, following regulatory manuals. GIS supports desktop screening with imagery, terrain indices, soil maps, and hydroperiod data, while field crews verify indicators and set flags for jurisdictional limits. Because wetlands are dynamic and seasonal, delineations should record dates, evidence, and uncertainty.
Application
Permitting, mitigation banking, habitat planning, and stormwater design depend on accurate delineation. Developers avoid costly redesigns by screening early.
FAQ
How do you handle seasonal variability in wetland indicators?
Use multi-date imagery and plan field visits during likely saturation; document off-season clues (drift lines, oxidized rhizospheres).
What role do soils play?
Hydric soils provide long-term evidence of saturation; soil surveys and field pits confirm presence when water is absent.
How should delineations be georeferenced and archived?
Collect GPS with stated accuracy, tie to a datum, store flags and polygons with photos and notes, and maintain versioned records.
What QA reduces boundary disputes?
Peer review, transparent criteria citations, and clear mapping symbology distinguishing core and buffer areas.