Drinking Water Quality

Wetlands improve water

quality in nearby rivers and

streams, and thus have

considerable value as filters

for future drinking water.

When water enters a wetland, it slows down and

moves around wetland

plants. Much of the suspended sediment drops out

and settles to the wetland

floor. Plant roots and

microorganisms on plant

stems and in the soil

absorb excess nutrients in

the water from fertilizers,

manure, leaking septic tanks and municipal sewage.

While a certain level of nutrients is necessary in

water ecosystems, excess nutrients can cause algae

growth that’s harmful to fish and other aquatic life.

A wetland’s natural filtration process can remove

excess nutrients before water leaves a wetland, making it healthier for drinking, swimming and supporting plants and animals. For example, the

Congaree Bottomland Hardwood Swamp in South

Carolina removes a quantity of pollutants from the

watershed equivalent to that which would be

removed by a $5 million treatment plant. (Source:

EPA832-R-93-005)

Flood Control

Flood damages in the U.S. average $2 billion each

year, causing significant loss of life and property.

(Source: National Oceanic and Atmospheric

Administration). Wetlands can play a role in reducing the frequency and intensity of floods by acting

as natural buffers, soaking up and storing a significant amount of floodwater. A wetland can typically

store about three-acre feet of water, or one million

gallons. An acre-foot is one acre of land, about

three-quarters the size of a football field, covered

one foot deep in water. Three acre-feet describes the

same area of land covered by three feet of water.

Coastal wetlands serve as storm surge protectors

when hurricanes or tropical storms come ashore. In

the Gulf coast area, barrier islands, shoals, marshes,

forested wetlands and other features of the coastal

landscape can provide a significant and potentially

sustainable buffer from wind wave action and storm

surge generated by tropical storms and hurricanes.

(Source: Working Group for Post-Hurricane

Planning for the Louisiana Coast) After peak flood

flows have passed, wetlands slowly release the stored

waters, reducing property damage downstream or

inland. One reason floods have become more costly

is that over half of the

wetlands in the United

States have been drained

or filled. The loss of more

than 64 million acres of

wetlands in the Upper

Mississippi Basin since the

1780’s contributed to high

floodwaters during the

Great Flood of 1993 that

caused billions of dollars

in damage. (Source:

“Flood Damage

Reduction in the Upper

Mississippi River Basin—

An Ecological

Economic Benefits of Wetlands

Wetlands contribute to the national and local economies by producing resources,

enabling recreational activities and providing other benefits, such as pollution

control and flood protection. While it can be difficult to calculate the economic value provided by a single wetland, it is possible to evaluate the range

of services provided by all wetlands and assign a dollar value. These

amounts can be impressive. According to one assessment of natural ecosystems, the dollar value of wetlands worldwide was estimated to be $14.9 trillion. (Source: Costanza et al. 1997) This fact sheet summarizes some of the

important ways in which wetlands contribute to the economy.

A wetland is a

natural area that

is often wet but

may not be wet all

year round.

Wetlands are characterized by their

distinctive hydrology, soils and

plants. Once

regarded as wastelands, wetlands

are now recognized as important features of the

landscape that

provide numerous

beneficial services

for people and

wildlife. The economic value of a

wetland is an estimate of the importance, or worth, of

one or more of its

services to society.

Some of these services, or functions,

include protecting

and improving

water quality, supporting the fishing

industry, storing

floodwaters and

providing opportunities for education and recreation. If wetlands

are destroyed or

damaged, it can

be difficult or

impossible to

replace all of these

functions.

$ $ $ $ $ $

Wetlands improve water 

quality in rivers and streams.

they are valuable filters for

water that may eventually

become drinking water.

One of the most valuable

benefits of wetlands is their

ability to store flood waters.

Maintaining only 15% of the

land area of a watershed in

wetlands can reduce flooding peaks by as much as

60%. (Source: The Wetlands

Initiative, EPA) (See EPA843-

F-06-001, “Wetlands and

Flooding.”)
Alternative”, 2004) The damage sustained by the

Gulf Coast during Hurricane Katrina could have

been less severe if more wetlands along the coast and

Mississippi delta had been in place.

Cleaning the Water

Because natural wetlands are so effective at removing pollutants from water that flows through them,

engineers and scientists construct systems that replicate some of the functions of natural wetlands.

These constructed treatment wetlands use natural

processes involving wetland vegetation, soils and

their associated microbial

life to improve water

quality. They are often

less expensive to build

than traditional wastewater and stormwater

treatment options, have

low operating and maintenance expenses and can

handle fluctuating water

levels. For example, in

1990 city managers in

Phoenix, Arizona, needed to improve the performance of a wastewater treatment plant to meet new

state water quality standards. After learning that

upgrading the plant might cost as much as $635

million, the managers started to look for a more

cost-effective way to provide final treatment to the

plant’s wastewater discharge into the Salt River. A

preliminary study suggested that a constructed wetland system would sufficiently clean the discharge

water while supporting high-quality wetland habitat

for birds, including endangered species, and protecting downstream residents from flooding. All these

benefits would be achieved at a lower cost than

retrofitting the existing treatment plant. As a result,

the 12-acre Tres Rios Demonstration Project began

in 1993 with assistance from the Corps of

Engineers, the Bureau of Reclamation and EPA’s

Environmental Technology Initiative and now

receives about two million gallons of wastewater per

day. This project is still flourishing, serving as a

home for thousands of birds and other wildlife.

(Source: City of Phoenix) There are hundreds of

wastewater treatment wetlands operating in the

United States today. (Source: EPA832-R-93-005)

Fisheries

The Nation’s wetlands are vital to fish health and

thus to the Nation’s multibillion dollar fishing

industry. Wetlands provide an essential link in

the life cycle of 75 percent

of the fish and shellfish

commercially harvested in

the U.S., and up to 90

percent of the recreational

fish catch. Wetlands provide a consistent food supply, shelter and nursery

grounds for both marine

and freshwater species.

Landings of crab, shrimp

and salmon were valued at

$1,167 billion in 2004. These species are dependent

on wetlands for at least part of their life cycles. In

2004 the dockside value of fin fish and shellfish

landed in the United States was $3.7 billion and was

the basis for the $7.2 billion fishery processing business. U.S. consumers spent an estimated $54.4 billion for fishery products in 2000. (Source: U. S.

Fish and Wildlife Service (USFWS), National

Oceanic and Atmospheric Administration (NOAA),

National Marine Fisheries Service (NMFS))

Recreation

Wetlands are often inviting places for popular recreational activities including hiking, fishing, bird

watching, photography and hunting. More than 82

million Americans took part in these activities in

2001, spending more than $108 billion on these

pursuits. (Source: USFWS, Ducks Unlimited). For

example, over 34 million people went fishing in

2001, spending an average of $1,046 and 16 days

each on the water. Anglers

spent $14.7 billion in

2001 for fishing trips, $17

billion on equipment and

$4 billion for licenses,

stamps, tags, land leasing

and ownership, membership dues, contributions

and magazines. The overall economic impact of

recreational fishing is estimated at $116 billion

(American Sportfishing

Association), and wetlands

play a crucial role in the

life cycle of up to 90 percent of the fish caught recreationally. In 2001,

approximately 3 million people hunted migratory

birds, and 6.5 million small mammals that are often

Valuation of

Wetlands

Although wetlands provide

important services to society,

these services are

typically not sold

nor do they have

market value.

Wetland benefits

can be estimated

by several standard market and

non-market valuation techniques.

The three most

common are

cost-benefit

analysis, costeffectiveness

analysis and benefits valuation for

compensation for

environmental

damages. The

techniques can be

applied whether

the change in the

environment is

an improvement

or degradation.

(Source:

“Economic

Valuation of

Environmental

Benefits”)

Natural wetlands are effective at cleaning the water

passing through them.

Wetland plants and soils

absorb much of the excess

nutrients in the water.

Wetlands perform this function so well that similar systems are being constructed

to treat wastewater.

Wetlands are essential to

our multi-billion dollar

National commercial fishing

industry. Wetlands have an

important place in the life

cycle of 75 percent of the

fish and shellfish commercially landed in U.S. waters.

Wetlands are pleasant

places for recreational activities like fishing. They may

provide a place of natural

beauty and solitude that can

be enjoyed by persons of all

ages who may seldom be

exposed to nature.

Anneke Davis
found in wetlands. They spent more than $2.2 billion, including

$111million paid by migratory bird and large game hunters to

lease hunting areas and blinds, often located on private property

with wetlands. (Source: U. S. Fish and Wildlife Service) Each

year nearly $200 million in hunters’ federal excise taxes are distributed to state agencies to support wildlife management programs, the purchase of lands open to hunters and hunter education and safety classes. Proceeds from the federal Duck Stamp, a

required purchase of migratory water fowl hunters, have purchased more than five million acres of habitat for the refuge system. (Source: Ducks Unlimited) Just watching the wildlife, many

of which depend on wetlands, has become a popular pastime.

More than 66 million people 16 years old and older--31% of all

Americans-- fed, photographed and observed wildlife in 2001

and spent $40 billion on their activities. (Source: U. S. Fish and

Wildlife Service)

Wildlife Habitat

Diverse species of mammals, plants,

insects, amphibians, reptiles, birds and

fish rely on wetlands for food, habitat

or shelter. Wetlands are some of the

most biologically productive natural

ecosystems in the world, comparable

to tropical rain forests or coral reefs in

the number and variety of species they

support. Although wetlands make up

only about 5 percent of the land area

of the lower 48 states, more than onethird of threatened and endangered

species live only in wetlands. An additional 20% of the country’s threatened

and endangered species use or inhabit

wetlands at some time in their life.

Some species must have a wetland in

order to reproduce. Migrating waterfowl rely on wetlands for

resting, eating and breeding areas, leading to increased populations. As noted, the appeal of wetlands and the diversity of

plant and animal life they attract contribute to or support many

businesses. (Source: U.S. Fish and Wildlife Service)

Other Commercial Benefits

Many industries, in addition to the fishing industry, derive benefits or produce products dependent on wetlands. Part of this

economic value lies in the variety of commercial products they

provide, such as food and energy sources. Rice can be grown in a

wetland during part of the year, and the same area can serve as a

wildlife habitat for the rest of the year. Some wetland plant

species, such as wild rice and various reeds, can be harvested for

or used to produce specialty foods, medicines, cosmetics and

decorative items. In many coastal and river delta wetlands, haying of wetland vegetation is important to livestock producers. In

Europe, reed-growing for building materials is undergoing a

revival in some countries as people realize the full potential of

reeds as a roofing material. Aesthetically pleasing, thatched roofs

are superior insulators to conventional tile roofs, and they have a

life span of 25-40 years. (Source: Ramsar) Fur-bearing animals,

such as mink, muskrat and beaver, use wetlands during some

part of their life cycle. Income can be derived from trapping

these furbearers, either by direct sale of their pelts or by leasing

wetlands for the fur harvest. The nation’s harvest of muskrat

pelts alone was worth $124 million in 2004. (Source: U.S. Fish

and Wildlife Service) Wetlands also provide employment opportunities, including such positions as surveyor or park ranger.

The production of raw materials from wetlands provides jobs to

those employed in the commercial fishing, specialty food and

cosmetic industries. These are billion dollar industries that

depend in part on wetlands to flourish.

In addition to the many ways wetlands provide economic benefits, they offer numerous less tangible benefits as well. These

include providing aesthetic value to residential communities,

reducing streambank erosion and providing educational opportunities as an ideal “outdoor classroom.” By nearly any measure

used, it pays to save wetlands.

Did You Know?

• Although wetlands cover only about 5 percent of the 

land surface in the lower 48 states, they are home to 31 

percent of plant species. (U.S. Fish and Wildlife Service)

• In 2002 Louisiana commercial fish landings exceeded 

1 billion pounds with a dockside value of $343 million 

– approximately 30% of the total catch by weight in the 

lower 49 states. (Source: America’s Wetland)

• Rivaling the likes of tropical rainforests and coral reefs, 

wetlands are among the most fertile, productive 

ecosystems in the world. (Source: Ramsar)

• Two thirds of all fish consumed worldwide are 

dependent on coastal wetlands at some stage in their life 

cycle. (Source: Ramsar)

• Annual fish and seafood production in swamps and 

marshes worldwide has been estimated at an average of 

nine tons per square kilometer, 259 hectares or 640 

acres. (Source: Ramsar)

• As many as one-half of all North American bird species 

nest or feed in wetlands. 

• Five to seven million migratory waterfowl, including the 

endangered whooping crane, use wetlands, i.e. prairie 

potholes, as resting and feeding areas and as an abundant 

food source. (Source: U.S. Fish and Wildlife Service)

Many species of wildlife rely

on wetlands for their very

existence. Wetlands provide

mammals, plants, amphibians, reptiles, birds and fish

with food, habitat, breeding

grounds and shelter. While

the diversity of wetland

wildlife contributes to many

businesses, they are also

inherently wonderful to

observe.

Patricia Deege

$ $ $ 
On the Internet:

American Sportfishing Association. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . www.asafishing.org

“A New Framework for Planning the Future of Coastal Louisiana after the 

Hurricanes of 2005.” Working Group for Post-Hurricane Planning for the 

Louisiana Coast. University of Maryland Center for Environmental Science . . . . . . . . . www.umces.edu/la-restore

“Constructed Wetlands for Wastewater Treatment and Wildlife Habitat:

17 Case Studies.” (EPA832-R-93-005) 1993. U.S. Environmental

Protection Agency, Washington, DC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . www.epa.gov/owow/wetlands

Ducks Unlimited . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . www.ducks.org

“Economic Valuation of Environmental Benefits” . . . . . . . . . . . . . . . . . . . . . . . . . . www.nemw.org/ERconval.htm

“Economic Valuation of Wetlands: A Guide for Policy

Makers and Planners” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . www.ramsar.org

“Flood Damage Reduction in the Upper Mississippi River Basin – An

Ecological Alternative.” 2004. Donald L. Hey, et al. The Wetlands

Initiative, Chicago, IL. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . www.wetlands-initiative.org

“National List of Plant Species that Occur in Wetlands: 1988 National

Summary.” Porter B. Reed for U.S. Fish and Wildlife Service in cooperation

with the U.S. Army Corps of Engineers, U.S. Environmental Protection

Agency, U.S. Soil Conservation Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . www.nwi.fws.gov/bha

National Marine Fisheries Service. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . www.nmfs.noaa.gov

National Oceanic and Atmospheric Administration. . . . . . . . . . . . . . . . . . . . . . . . . . . . www.noaa.gov/floods.html

“National Survey of Fishing, Hunting and Wildlife-Associated Recreation” . . . . . . . . . . . . . . . . . . . . www.fws.gov

“Status and Trends of Wetlands in the Conterminous 

United States 1998 to 2004. . . . . . . . . . . . . . . . . . . . . . . . http://wetlandsfws.er.usgs.gov/status_trends/index.html

In Print:

Constanza, R. R., R. d’Arge, R. de Groot, S. Farber, M. Grasso, B. Hannon, K. Limburg, S. Naeem, R.V. O”Neill, 

J. Paruelo, R.G. Raskin, P. Sutton, and M. van der Belt. 1997. “The value of the world’s ecosystem services and 

natural capital.” Nature 387:253-260

For additional information, visit the U.S. EPA’s website (www.epa.gov/owow/wetlands), or call 

the toll-free Wetlands Helpline at 1-800-832-7828.

References

EPA843-F-06-004

Office of Water

May 2006