RecognizingWetlands

US Army Corpsof Engineers

Pitcher plant

1998 Edition

For additional information contact yourlocal U.S. Army Corps of Engineers office.

What is a wetland?

A wetland is an area that is covered by shallowwater or has waterlogged soils for long periodsduring the growing season in most years. Pro-longed saturation with water leads to chemicalchanges in wetland soils, which in turn affect thekinds of plants that can grow in wetlands. There-fore, wetland vegetation often looks quite differ-ent from that of surrounding non-wetland areas.

Wetlands are known by many different names,some of which are specific to particular regionsof the country. Wetlands that are dominated bytrees and shrubs are commonly called swamps.Swamp forests associated with rivers and streamsin the Southeast are locally known as bottomlandhardwoods. Wetlands that consist of herbaceousvegetation, such as sedges, cattails, and bul-rushes, are known as marshes. Marshes arehighly variable and include fens, sloughs, pot-holes, and wet meadows. Bogs are generallydominated by sphagnum moss, which, when itdies, builds up in thick layers of peat. Extensivebogs in Canada and Alaska are called muskegs.

The information presented here willhelp you to determine whether youhave a wetland on your property. If youintend to place fill material in a wetlandor in an area that might be a wetland,contact the local District Office of theU.S. Army Corps of Engineers (Corps)for assistance in determining if a permitis required.

Why is it necessary toconsider whether anarea is a wetland?

Section 404 of the Clean Water Actrequires that anyone interested in plac-ing dredged or fill material into “watersof the United States, including wet-lands” must first obtain a permit fromthe Corps. Activities in wetlands forwhich Section 404 permits may berequired include, but are not limited to:

• Placement of fill and/or dredgedmaterial.

• Ditching activities when the exca-vated material is sidecast.

Watershed view of wetlands associated with a lake ecosystem

Wetland fill activity

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• Levee and dike construction.• Mechanized land clearing.• Land leveling.• Most road construction.• Dam construction.

The final determination of whether an area isa wetland and whether the activity requires apermit must be made by the appropriate CorpsDistrict Office.

How do wetlands benefitpeople?

One of the goals ofthe Clean Water Actis to prevent the degra-dation of the Nation’swaters, includingneedless destructionof wetlands. Wetlandsbenefit people inmany ways that maynot be obvious.Depending upon their location, wetlands provideone or more of the following benefits:

• They improve the quality of our waterby filtering sediments and removingcontaminants.

• They serve as spawning sites and nurs-ery areas for fish and other aquatic life.

• They support downstream aquatic sys-tems, including commercial and sportfisheries, by producing food andorganic material that is flushed out ofthe wetlands and into streams duringhigh flows.

• They reduce flood damage to cropsand human settlements downstream by

storing flood water and releasing it slowly,like a giant sponge.

• They are breeding, feeding, and winteringhabitat for hundreds of wildlife speciesincluding: waterfowl, shorebirds, muskrats,turtles, frogs, and salamanders.

• They support many endangered species ofanimals and plants.

• They protect shorelines from erosion due towaves and currents.

• They provide recreational opportunities, suchas hunting, fishing, boating, and wildlifewatching.

Wetlands help prevent flooddamage

Wetlands help improve water quality

Wetlands provide habitat for wildlife

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How are wetlands recognized?

The term “wetland” encompasses a variety ofconditions and degrees of wetness. Some wet-lands are very easy to recognize because the

water sits on theland’s surfacefor much of theyear. Other wet-lands exist dueto saturation ofthe soil bygroundwater andcan be difficultto identify. Wet-

lands do not need to be wet year-round. In fact,due to seasonal variations in rainfall and otherenvironmental conditions, most wetlands lackboth surface water and waterlogged soils duringat least part of the growing season each year.

One clue that a tract of land may containwetlands is its topography or position in thelandscape. Wetlands occur in areas where waternaturally flows or accumulates, such as in thefloodplains of streams and rivers, along smallercreeks and washes, in low spots or depressions inflat or rolling landscapes, around seeps andsprings, along the fringes of ponds and lakes, andin coastal areas affected by tides.

Even in fairly obvious wetland situations, itmay be difficult to determine where the wetlandends and the upland begins. Therefore, identifica-tion of wetland boundaries (a procedure calledwetland delineation) is a task best left to aqualified wetland consultant or Corps Districtpersonnel. Wetlands are delineated by carefullyexamining a site for the presence of wetland indi-cators. Three categories of wetland indicators —vegetation, soil, and hydrology — are explainedbriefly in the following sections.

Vegetation indicators

Wetland delineators identify wetland vegeta-tion – called hydrophytic vegetation – by makinga list of the most abundant plant species in thearea and looking up those species on the appropri-ate regional version of the National List of PlantSpecies that Occur in Wetlands published by theU.S. Fish and Wildlife Service (see the last pagefor information on obtaining a copy). Of theroughly 22,500 plant species in the United States,over 6,700 commonly grow in wetlands. How-ever, you can often determine if wetland vegeta-tion is present by knowing a relatively few plantspecies that commonly grow in wetlands in yourarea. For example, cattails, bulrushes, sedges,

Mangrove wetland

Freshwater wetland

Skunk cabbage

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rushes, cordgrass, sphagnum moss, baldcypress,tupelo gum, willows, buttonbush, mangroves,pickleweed, and arrowheads usually occur inwetlands.

Other evidence of wetland vegetation includestrees with shallow root systems, swollen trunks,and roots growing from the plant stem or trunkabove the soil surface. Several Corps officeshave published pictorial guides to representativewetland plant types, and other references to plantidentification are available in bookstores. If youcannot determine whether the plant species inyour area are those that commonly occur in wet-lands, ask your Corps District Office or a localbotanist for assistance.

Soil indicators

Wetland soils – called hydric soils – are identi-fied in the field by digging a shallow hole(roughly 1 to 1½ feet deep) and examining thesoil for evidence of long-term saturation duringthe growing season. Soils that are waterlogged

for long periods become depleted in oxygen. Inturn, the lack of oxygen (1) retards normal break-down of dead plant debris, causing partlydecomposed organic matter to accumulate on the

soil surface, and (2) produceschemical changes in the soil,which can affect its color andodor. For example, presence ofany one of the following charac-teristics may indicate a hydric soil:

• Soil has a layer of partiallydecomposed plant material (peator muck) on the surface.

• Soil color below the surface ispredominantly grayish (com-pared with an upland soil samplefrom the same area), with orwithout spots or blotches oforange or brown.

• Soil has the sulfurous odor ofrotten eggs.Vernal pool plant community

Soil sampling

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• Soil is very sandy and has a black surfacelayer.

• Soil is very sandy and appears blotchy or hasdark streaks of organic matter below thesurface.

Another way to determine whether a particulararea might contain hydric soils is to check theSoil Survey Report for your county published bythe USDA Natural Resources ConservationService (NRCS). Map sheets given in the SoilSurvey Report will tell you the name(s) of thesoils on your property. You then look up thesesoils on a list of hydric soils in the county. Askyour county NRCS office for help in using SoilSurvey Reports and hydric soil lists to determinewhether you might have areas of hydric soil onyour property.

Hydrology indicators

Wetland hydrology refers to the presence ofsurface water or waterlogged soils for a sufficientperiod of time in most years to influence thekinds of plants and soils that occur in an area.The most reliable evidence of wetland hydrologyis provided by gaging stations or groundwaterwells, but such information is limited in mostareas and, when available, requires analysis bytrained individuals.

Wetland delineators more often use hydrologicindicators that can be observed during a fieldinspection. For example, the following indicatorsprovide evidence of periodic flooding or soilsaturation:

Gray color indicates wetland soil

Samplingcore

Watermark in seasonally-flooded wetland

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• Standing or flowing water is observed on thearea during the growing season.

• Soil is observed to be waterlogged during thegrowing season.

• Watermarks are present on trees and othererect objects. These indicate the approximatedepth of standing or flowing water.

• Drift lines or small piles of debris depositedby flowing water are present. These oftenoccur along contours and indicate the approxi-mate extent of flooding in an area.

• Thin layers of sediment coat leaves or otherobjects on the ground, caused when sus-pended particles settle out of flood watersover a period of time.

• Plant roots have rust-colored coatings orzones of soil around them. Under water-logged conditions, these are caused by leak-age of oxygen out of plant roots, resulting inoxidation of iron compounds in the soilaround the root.

Wetland determinations

Corps policy requires that at least one indica-tor from each category – vegetation, soil, andhydrology – must be present for an area to beidentified as a wetland under Section 404 of theClean Water Act. However, if you observe anyof the indicators described in this brochure, youshould seek assistance from either your localCorps District Office or someone who is anexpert at delineating wetlands. This brochure pro-vides general information only; it is not intendedto be used to make a final wetland delineation!

What to do if your propertyhas wetlands that you proposeto alter

Contact the Corps District Office that hasresponsibility for the Section 404 permitting proc-ess in your area. This office will assist you indefining the boundary of any wetlands on yourproperty, and will provide instructions for apply-ing for a Section 404 permit, if necessary.

Wetland Delineator uses soil color chart to make awetland determination

Drift line in tidal marsh

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Sources of information formaking wetland delineations

The Corps of Engineers Wetlands DelineationManual is available on the Internet in “.pdf”format at http://www.wes.army.mil/el/wetlands/wlpubs.html or can be purchased from:

National Technical Information Service (NTIS)5285 Port Royal RoadSpringfield, VA 22161To place an order: (703) 487-4650For help in identifying a title for sale:

(703) 487-4780

The U.S. Fish and Wildlife Service NationalList of Plant Species that Occur in Wetlands isavailable on the Internet at http://www.nwi.fws.gov/ecology.html or can be purchased fromNTIS above.

County Soil Survey Reports and hydric soillists are available from county Natural ResourcesConservation Service offices.

Information on wetland laws and regulations isavailable from the U.S. Army Corps of Engineers(http://www.usace.army.mil/inet/functions/cw/cecwo/reg/).

Front Cover Photo: Salt marsh

Sedimentation trap — a wetland function

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