Defining wetland boundaries
Legal and ecological wetland delineation combines hydrology, hydric soils, and hydrophytic vegetation. All three indicators must be present during growing season for jurisdictional wetland status in many regulatory frameworks.
Hydrologic indicators
- Standing water or saturated soil in root zone.
- Water stains, drift lines, and sediment deposits.
- Rooted aquatic plants and floating mats.
Vegetation zones
OBL (obligate wetland) species almost always occur in wetlands. FACW (facultative wetland) usually in wetlands. Regional indicator lists assign wetland probability scores.
Seasonal dynamics
Ephemeral wetlands dry seasonally — timing of survey matters. Permanent saturation supports different communities than floodplain forests with brief spring inundation.