Wetland delineation

Wetland Delineation: 

Wetland Delineation

Major Areas Evaluated to Determine Presence of Wetland: 

Major Areas Evaluated to Determine Presence of Wetland Soils – evidence of past presence of water Plants – wetland obligate or facultative Hydrology – sufficient to cause wetland plant and soil characteristics Note: for ACOE definition  all three are needed for EPA any one of three IMHO – two out of three probably a good compromise

Wetland soils: 

Wetland soils

Wetland Soils: 

Wetland Soils Usually high in organics Show evidence of eluviation called alluvial soils, usually found in B horizon  nutrients leached out by water so only clay is left. Generally soils are the best indicators of wetlands because alluvial soils will still be there even after most disturbances

Slide6: 

Evaluating the soil for wetland characteristics

Slide7: 

Mottled soils have a matrix of one color with blotches and flecks of other colors Gleyed soils are usually light grey with a bluish or greenish tint (chroma of 1 or less).

Wetland Hydrology: 

Wetland Hydrology “The area is inundated either permanently or periodically at mean water depths <6.6 ft [2 m], or the soil is saturated to the surface at some time during the growing season of the prevalent vegetation.” (Corps of Engineers Wetlands Delineation Manual 1987)

Slide12: 

Evidence for wetland hydrology on cypress tree trunks

Wetland Plants: 

Wetland Plants “Areas that are inundated or saturated by surface or ground water at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions” Corps of Engineers Wetlands Delineation Manual, 1987 hydrophytic vegetation - capable of growing, competing, and reproducing in saturated soils which produce, contain, or maintain anaerobic conditions.

Wetland Plants: 

Wetland Plants Have to be able to tolerate anoxia because roots are covered with water Types of wetland plants Obligate – found in wetlands 100% of the time, require inundation. If find any  wetland! Facultative wetland – found in wetlands 66 to 99%  preponderance  wetland! Mixture of facultative wetland/facultative/upland – need to take a closer look

Slide15: 

            Revised . Hosted by Jagged Peak, Inc. © 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005. Richard Chinn Environmental Training, Inc.  All rights reserved. Evaluating for wetlands plants

Wetland Plants: 

Wetland Plants

Areas Likely to Contain Wetlands: 

Areas Likely to Contain Wetlands Area occurs in a floodplain or otherwise has low spots in which water stands at or above the soil surface during the growing season. Caution: Most wetlands lack both standing water and waterlogged soils during at least part of the growing season. Area has plant communities that commonly occur in areas having standing water for part of the growing season (eg. Cypress-gum swamps, cordgrass marshes, cattail marshes, bulrush and tule marshes, and sphagnum bogs). Area has soils that are called peats or mucks. Area is periodically flooded by tides, even if only by strong, wind-driven, or spring tides.

Slide19: 

Used in draft supplement of 1987 delineation manual

Wetland Mitigation: 

Wetland Mitigation Replace destroyed wetland with artificially constructed one Often fail  use mitigation ratio Open water 1.5:1 Grasses, wildflowers 2:1 Scrub/Shrub 3:1 Forested land 3-4:1 Note: under certain circumstances the mitigation ratio could be as high as 10:1.