Chapter 7
Wetlands

WHAT ARE WETLANDS?

Wetlands are transition zones between land and aquatic systems where the water table is usually near or at the surface, or the land is covered by shallow water. Wetlands range in size from less than one acre to thousands of acres and can take many forms, some of which are immediately recognizable as "wet." Other wetlands appear more like dry land, and are wet during only certain seasons of the year, or at several year intervals. The U.S. Army Corps of Engineers reports that most U.S. wetlands lack surface water and waterlogged soils during at least part of each growing season.

Some of the more commonly recognized types of wetlands are marshes, bogs, and swamps. Marshes are low-lying wetlands with grassy vegetation. Bogs are wetlands that accumulate wet, spongy, acidic, dead plant material called peat. Shrubs, mosses, and stunted trees may also grow in bogs. Swamps are low-lying wetlands that are seasonally flooded; they have more woody plants than marshes and better drainage than bogs.

According to Thomas E. Dahl, in Status and Trends of Wetlands in the Conterminous United States 1998 to 2004 (2006, http://wetlandsfws.er.usgs.gov/status_trends/national_reports/trends_2005_report.pdf), there were an estimated 107.7 million acres of wetlands in the forty-eight coterminous states in 2004. This constituted about 5.5% of the total land area, whereas deepwater (rivers and lakes) constituted 1% and upland ("dry" land) constituted most of the total land area at 93.5%. (See Figure 7.1.) Of the wetland areas, 95% were freshwater and 5% were estuarine (coastal saltwater). (See Figure 7.2.) Dahl does not include data on Alaska and Hawaii, but the U.S. Environmental Protection Agency (EPA) notes in "Wetlands: Status and Trends" (February 22, 2006, http://www.epa.gov/OWOW/wetlands/vital/status.html) that in the 1980s an estimated 170 to 200 million acres of wetlands existed in Alaska—covering slightly more than half of the state—and Hawaii had 52,000 acres.

Hydrology and Wetland Formation

Wetlands are distributed unevenly, but occur in every state and U.S. territory. (See Table 7.1.) They are found wherever climate and landscape cause groundwater to discharge to the land surface or prevent rapid drainage from the land surface so that soils are saturated for some time.

In wetlands, when the soil is flooded or saturated, the oxygen used by the microbes and other decomposers in the water is slowly replaced by oxygen in the air, because oxygen moves through water about ten thousand times slower than through air. Thus, all wetlands have one common trait: hydric (oxygen-poor) soils. As a result, plants that live in wetlands have genetic adaptations in which they are able to survive temporarily without oxygen in their roots, or they are able to transfer oxygen from the leaves or stem to the roots. This anaerobic (without oxygen) condition causes wetland soils to have the sulfurous odor of rotten eggs.

Local hydrology (the pattern of water flow through an area) is the primary determinant of wetlands. Wetlands can receive groundwater in-flow, recharge ground-water, or experience both inflow and outflow at different locations. Figure 7.3 illustrates water movement in several different wetland situations. Part A in Figure 7.3 shows how wetlands do not always occupy low points and depressions in the landscape. They can occur in flat areas that have complex underground water flow.

Part B in Figure 7.3 shows a fen, which is a type of wetland that accumulates peat deposits like bogs do. Fens, however, are less acidic than bogs and receive most of their water from groundwater rich in calcium and magnesium. As part B shows, fens occur on slopes at groundwater seepage faces and are subject to a continuous supply of the chemicals that are dissolved in the groundwater.

Land along the sides of streams or rivers receives a continuous water supply and is ideal for wetland growth. It may also receive some groundwater discharge, as shown in part C in Figure 7.3. Bogs, shown in part D in Figure 7.3, are wetlands normally found on uplands or extensive flatlands. Most of their water and chemistry comes from precipitation.

Riverine (areas along streams, rivers, and irrigation canals) and coastal area wetlands are highly subject to periodic water level changes. Coastal area wetlands, for example, are affected by predictable tidal cycles. Other coastal and riverine wetlands are highly dependent on flooding and seasonal water level changes. Some examples are the floodplains of the Illinois and Missouri rivers.

TYPES OF WETLANDS

A wide variety of wetlands exist across the United States because of regional and local differences in hydrology, water chemistry, vegetation, soils, topography, and other factors. There are two large groups of wetlands: estuarine (coastal) and freshwater (inland). (See Figure 7.2.) Estuarine wetlands are linked to estuaries and oceans and are places where fresh- and saltwater mix, such as a bay or where a river enters the ocean. In estuaries the environment is one of ever-changing salinity and temperature. The water level fluctuates in response to wind and tide. Examples of estuarine wetlands are saltwater marshes and mangrove swamps.

The most common location of freshwater wetlands is the floodplains of rivers and streams, the margins of lakes and ponds, and isolated depressions surrounded by dry land. Some examples of inland wetlands are the Florida Everglades, wet meadows, swamps, fens, bogs, prairie potholes, playa lakes, and wet tundra.

Wetlands are further divided by their vegetation. Emergent wetlands (marshes and wet meadows) are dominated by grasses, sedges, and other herbaceous (non-woody) plants. Emergent wetlands account for 73% of estuarine wetlands, even though they represent only 25.5% of freshwater wetlands. (See Figure 7.2.) Shrub wetlands (including shrub swamps and bogs), which are characterized by low-to-medium-height woody plants, make up 13% of estuarine wetlands and account for 17% of freshwater wetlands. Forested wetlands, mostly wooded swamps and bottomland hardwood forests, are dominated by trees and account for 51% of freshwater wetlands. (Bottomland hardwood forests are generally found along the edges of lakes and rivers and in sinkholes.)

HOW WETLANDS FUNCTION

Wetlands provide essential ecological functions that benefit people and the ecological systems surrounding the wetlands, as well as the wetland itself. The plants, microbes, and animals in wetlands are all key players in the water, nitrogen, carbon, and sulfur cycles.

Wetland functions fit into several broad categories:

• High plant productivity
• Temporary water storage
• Trapping of nutrients and sediments
• Soil anchoring

Not all wetlands perform all functions, nor do they perform all functions equally. The location of the wetland in the watershed and its size determine how it functions. (A watershed is the land area that drains to a stream, river, or lake.) Other factors that affect wetland function are weather conditions, quality and quantity of water entering the wetland, and human alteration of the wetland or the land surrounding it. The values of wetland functions to human communities depend on the complex relationships between the wetland and the other ecosystems in the watershed. An ecosystem consists of all the organisms in a particular area or region and the environment in which they live. The elements of an ecosystem all interact with each other in some way and depend on each other either directly or indirectly. (See Figure 7.4.)

Wetlands—Nursery, Pantry, and Way Station

Wetlands are diverse and rich ecosystems, which provide food and shelter to many different plants and animals. The combination of shallow water, high nutrient levels, and primary productivity (plant growth and reproduction) is perfect for the development of organisms that form the base of the food chain. The water, dense plants, their root mats, and decaying vegetation are food and shelter for the eggs, larvae, and juveniles of many species. Smaller animals avoid predators by hiding among the vegetation while they wait to prey on still smaller organisms. Fish of all sizes seek the warmer, shallow waters to mate and spawn, leaving their young to grow on the rich diet provided by the wetlands. Food and organic material that is flushed out of wetlands and into streams and rivers during periods of high water flow feed downstream aquatic systems, including commercial and sport fisheries.

Estuarine marshes, for example, are among the most productive natural ecosystems in the world. They produce huge amounts of plant leaves and stems that make up the base of the food chain. When the plants die, decomposers such as bacteria in the water break them down to detritus (small particles of organic material). Algae that grow on plants and detritus are the principal foods for shellfish such as oysters and clams, crustaceans such as crabs and shrimp, and small fish. Small fish are the food for larger commercial species such as striped bass and bluefish. (See Figure 7.5.) The EPA states in Wetlands Functions and Values (March 19, 2007, http://www.epa.gov/watertrain/wetlands/module08.htm) that "the fish and shellfish that depend on wetlands for food or habitat constitute more than 75% of the commercial and 90% of the recreational harvest."

Both estuarine and freshwater wetlands also serve as way stations for migrating birds. The Central Flyway extending from south-central Canada through the north-central United States and into Mexico, for example, provides resting places and nourishment for migratory birds (which individually number in the millions) during the migration season. Without this stopover area, the flight to their Arctic breeding grounds would be impossible. Chesapeake Bay with its extensive tidal and freshwater marshes on the East Coast Atlantic Flyway gives winter refuge to thousands of ducks and geese.

Wetlands' Role in Biodiversity

Wetlands are the source of many natural products, including furs, fish and shellfish, timber, wildlife, and wild rice. A wide variety of species of microbes, plants, insects, amphibians, reptiles, fish, birds, and other animals make their homes in or around wetlands because of the availability of water. For others, wetlands provide important temporary seasonal habitats. Physical and chemical features such as landscape shape (topology), climates, and abundance of water help determine which species live in which wetland.

In "Wetlands and People" (February 22, 2006, http://www.epa.gov/owow/wetlands/vital/people.html), the EPA notes that "more than one-third of the United States' threatened and endangered species live only in wetlands." When wetlands are removed from a watershed or are damaged by human activity, the biological health of the watershed declines. Wetland health has a commercial impact as well. Dahl indicates that 75% of the fish and shellfish commercially harvested in the United States and up to 90% of the recreational fish rely directly or indirectly on wetlands for their survival. Dahl also notes that in 2004, 72% of freshwater mussels were imperiled and 39% of native freshwater fish species were at risk of extinction.

Waterfowl are birds such as ducks and geese that spend much of their lives in wetlands, lakes, rivers, and streams. The well-being of waterfowl populations is tied directly to the status and abundance of wetland habitats. According to the U.S. Fish and Wildlife Service's (USFWS) Division of Bird Habitat Conservation (December 12, 2006, http://www.fws.gov/birdhabitat/NAWMP/index.shtm), waterfowl are the most well-known and economically important group of migratory birds in North America. By 1985 (when waterfowl populations had decreased to record lows) approximately 3.2 million people were spending nearly $1 billion annually to hunt waterfowl. In addition, about 18.6 million people spent $2 billion on "waterfowl-watching" activities, such as observing and photographing them.

Measures to preserve and protect the waterfowl population include the North American Waterfowl Management Plan. A joint strategy adopted by the governments of the United States, Canada, and Mexico, the plan established an international committee with six representatives from each of the three countries. Its purpose is to provide a forum for discussion of major, long-term international waterfowl issues and to make recommendations to the directors of the three countries' national wildlife agencies. The Division of Bird Habitat Conservation notes that as of the end of 2006, $4.5 billion had been invested under the plan to protect, restore, and/or enhance 15.7 million acres of waterfowl habitat. North American Waterfowl Management Plan projects also target all wetland-associated species in their conservation efforts.

Water Storage

Wetlands absorb water, much like sponges. By temporarily storing runoff and flood waters, wetlands help protect adjacent and downstream property owners from flood damage. Wetland plants slow the flow of water, which contributes to the wetland's ability to store it. The combined effects of storing and slowing the flow of water permit it to percolate through the soil into groundwater, which recharges aquifers, and to move through the watershed with less speed and force.

Wetlands are particularly valuable in urban areas because paved and other impermeable surfaces shed water, increasing the rate, velocity, and volume of runoff so that the risk of flood damage increases. Loss or degradation of wetlands indirectly intensifies flooding by eliminating absorption of the peak flows and gradual release of floodwaters.

Nutrient and Sediment Control

Figure 7.6 shows how wetlands improve the quality of water. Wetlands act like natural water filters. When water is stored or slowed down in a wetland by the plants and root masses that grow there, sediment settles out and remains in the wetland so that the water leaving the area is much less cloudy than the water that entered. The loss of cloudiness or turbidity has important consequences for both human health and the ecological health of the watershed. Turbidity has been implicated in disease outbreaks in drinking water. Furthermore, turbid water bearing silt has been responsible for smothering plants and animals in rivers, streams, estuaries, and lakes.

Wetlands can also trap nutrients (phosphorous and nitrogen) that are dissolved in the water or attached to the sediment. Nutrients are either stored in the wetland soil or used by the plants to enhance growth. If too much nutrient material reaches rivers, streams, lakes, and reservoirs, it can cause eutrophication, resulting ultimately in the death of many aquatic organisms. (See Figure 6.12 in Chapter 6 and the related discussion.)

Soil Anchoring

Wetlands also play an important role in soil anchoring. The thick mesh of wetland vegetation and roots acts like a net and helps hold soil in place even during periods of relatively high water flow. Removing wetland vegetation the lines a stream or river leads to poorly anchored soil and an increased water flow, which carries away the soil. The result can be severe erosion and changes to the contours of channels, making them deeper and flatter. As a result, aquatic communities at the erosion location are disrupted or eliminated, and downstream aquatic systems are damaged by silt.

Marsh plant fringes in lakes, estuaries, and oceans protect shorelines from erosion in a similar fashion. The plants reduce soil erosion by binding the soil in their root masses. At the same time, the plants and root masses cushion the force of wave action, retarding scouring of shorelines.

ECONOMIC BENEFITS OF WETLANDS

Appreciation of the economic value of wetlands has undergone a dramatic change since the 1970s. Before that time, wetlands were considered useless, good only for taking up space and breeding mosquitoes. The emphasis was on filling and draining wetlands to turn them into productive land for development and agriculture. In the mid-1970s the growing environmental movement with its emphasis on clean water led to a closer examination of wetlands and their role in watersheds and the global ecosystem. Wetlands are now valued not only for their ecological role but also for their contribution to the economy.

Recreation

Some of the most popular recreational activities, including fishing, hunting, and canoeing, occur in and are dependent on healthy wetlands. The EPA notes in the fact sheet "Economic Benefits of Wetlands" (February 22, 2006, http://www.epa.gov/owow/wetlands/facts/fact4.html) that "more than half of all U.S. adults (98 million people) hunt, fish, birdwatch, or photograph wildlife." In 1991 spending on these activities amounted to $59.5 billion. Figure 7.7 shows that 42% of Americans who observed, fed, or photographed wildlife on trips away from home in 2001 visited wetlands for these activities.

An example of the value of these wetland-related recreational activities can be found in the USFWS's 2001 National Survey of Fishing, Hunting and Wildlife -Associated Recreation (October 2002, http://www.census.gov/prod/2002pubs/FHW01.pdf). The USFWS states that in 2001, 34.1 million people aged sixteen years and older went fishing and spent an average of $1,046 each; 28.4 million anglers went freshwater fishing and 9.1 million went saltwater fishing. Overall, anglers spent $35.6 billion in 2001 on fishing trips, $4.6 billion on equipment, $6 billion on food and lodging, and $3.5 billion on transportation. They spent nearly $5.3 billion on land-use fees, guide fees, equipment rental, boating expenses, and bait. Camping equipment, binoculars, and special fishing clothing accounted for $721 million in expenditures. Equipment such as boats, vans, and cabins cost $11.6 billion. Anglers spent $3.2 billion on land leasing and ownership and $860 million on magazines, books, membership dues and contributions, licenses, stamps, tags, and permits.

Jerry Leonard reports in Fishing and Hunting Recruitment and Retention in the U.S. from 1990 to 2005: Addendum to the 2001 National Survey of Fishing, Hunting, and Wildlife-Associated Recreation (February 2007, http://library.fws.gov/nat_survey2001_recruitment.pdf) that wetland-related activities are also important to children of all ages. In 2005, 64% of all first-time anglers were aged twenty or younger. In addition, 42% of children of any age living at home were exposed to fishing for the first time in 2005—49% of males and 35% of females.

Commercial Fisheries

The National Marine Fisheries Service notes in Fisheries of the United States 2005 (February 2007, http://www.st.nmfs.gov/st1/fus/fus05/fus_2005.pdf) that the value of the U.S. commercial fish landings (the part of the fish catch that is put ashore) in 2005 was $3.9 billion. Nearly 30% of the value of U.S. finfish landings was from species that are dependent on near-coastal waters and their wetlands for breeding and spawning. The EPA estimates in the National Coastal Condition Report II (2005) (December 2004, http://www.epa.gov/owow/oceans/nccr/2005/Chapt1_Intro.pdf) that "95% of commercial fish and 85% of sport fish spend a portion of their life cycles in coastal wetland and estuarine habitats. Adult stocks of commercially harvested shrimp, blue crabs, oysters, and other species throughout the United States are directly related to wetland quality and quantity."

Flood Control

Because wetlands function like sponges by absorbing and storing water, they help control flood waters and the resultant loss of life and property. In Economic Benefits of Wetlands (May 2006, http://www.epa.gov/OWOW/wetlands/pdf/EconomicBenefits.pdf), the EPA notes that floods in the United States cost about $2 billion annually. However, depending on their size, wetlands can store millions of gallons of water and then release the water slowly after the flood surge has passed, reducing flood damage. Wetlands can also buffer the effects of coastal tropical storms and hurricanes. The EPA suggests that if the Mississippi-Louisiana coastline had more wetland areas, then the effects of Hurricane Katrina would have been lessened.

HISTORY OF WETLANDS USE

Until well into the twentieth century wetlands were considered nature's failure, a waste in nature's economy. For this reason, people sought to increase the usefulness of wetlands. In the agricultural economy of that time, land unable to produce crops or timber was considered worthless. Many Americans began to think of draining these lands, an undertaking that required government funds and resources.

In the nineteenth century state after state passed laws to facilitate drainage of wetlands by the formation of drainage districts and statutes. When a number of landowners in an area petitioned for a drainage project, a hearing was held. A district encompassing the area affected could be created with the power to issue bonds, drain the area, and bill the landholders—petitioners and opponents alike. Coupled with an agricultural boom and technological improvements, reclamation projects multiplied in the late nineteenth and early twentieth centuries. The farmland under drainage doubled between 1905 and 1910 and again between 1910 and 1920. By 1920 state drainage districts in the United States encompassed an area larger than Missouri.

Early Conservationists

The earliest effective resistance came from hunters, sportsmen, and naturalist lobbies. Organizations such as the Izaak Walton League, the Audubon Society, and the American Game Protective Association deplored the destruction by drainage of wildlife habitats and began to press for protection of wetlands. These early conservation efforts met chilly receptions both from the public and the courts. A growing number of Americans, however, were beginning to sympathize with conservationists. Drainage projects were often disappointing—soils had proven to be poorer than expected, and the costs were generally greater than expected.

Reclamation's Failures

Lower Klamath Lake in Northern California became a striking example of reclamation's potential for creating wastelands far more desolate than those they replaced. The lake, a shallow sheet of water fringed by marshes, had been set aside by Theodore Roosevelt in 1908 as a waterfowl sanctuary. Nonetheless, in 1917 the water inflow was cut off to reclaim the land. The lakebed dried up and became prey to dust storms. The peat in the marsh bottom caught fire. Rather than being a reclaimed area of extraordinary fertility, the former wetlands became an ecological travesty. According to the USFWS's Klamath Basin National Wildlife Refuges (April 7, 2007, http://www.fws.gov/klamathbasinrefuges/history.html), even though time has helped reverse the damage, less than 25% of the historic wetland basin remains. In spite of this, the basin continues to support tremendous bird life on a smaller scale.

Efforts were made to help the Klamath Basin recover. According to the news release "President Bush to Propose Record-Level $3.9 Billion for Conservation Programs" (January 30, 2003, http://www.usda.gov/wps/portal/), the U.S. Department of Agriculture (USDA) reports that in the budget for fiscal year 2004, President George W. Bush proposed setting aside $8 million for water conservation and water quality enhancements in the Klamath Basin. The article "Federal Agencies Issue Final Mandates for Klamath Dams" (California Chronicle, January 30, 2007) notes that the Departments of Interior and Commerce mandated that fishways and fish ladders be operational in the area, making it economically favorable to remove dams that blocked water to the area, rather than relicensing the dams and providing fishways and ladders using alternative methods. This action led the way toward returning the Klamath River to being a productive salmon river.

Similarly, for many years Florida sought to drain the Everglades, a vast wetland region covering much of the southern part of the state. Efforts there resulted in lands prone to flooding and peat fires. Peat fires are particularly dangerous because they burn underground and can flare up without warning long distances from where they were originally ignited. Costs escalated, and the drainage district went broke. Across the nation the gap between the cost and the value of reclaimed land widened even more. The agricultural depression beginning in the 1920s increased the growing skepticism as to the value of reclamation. Nonetheless, during the Great Depression (1929–39), programs such as the Works Progress Administration and the Reconstruction Finance Corporation encouraged wetland conversion as a way to provide work for many unemployed people. By the end of World War II (1939–45) the total area of drained farmland had increased sharply.

Concern over Property Rights

Dispute over wetlands regulation reflects the nation's ambivalence when private property and public rights intersect, especially because three-fourths of the nation's wetlands are owned by private citizens. In recent years many landowners have complained that wetlands regulation devalued their property by blocking its development. They argued that efforts to preserve the wetlands have gone too far, citing instances where a small wetland precludes the use of large tracts of land. Many people believe this constitutes taking without just compensation.

The "takings" clause of the U.S. Constitution provides that when private property is taken for public use, just compensation must be paid to the owner. Wetland owners claim that when the government, through its laws, eliminates some uses for their land, the value is decreased, and they believe they should be paid for the loss.

In the 1970s and 1980s state courts and the lower federal courts frequently handed down contradictory rulings on the issue of compensation for wetland-related takings. In 1992 the U.S. Supreme Court, in Lucas v. South Carolina Coastal Council (505 U.S. 1003), resolved the issue of compensation when land taken for an accepted public good loses significant value.

David Lucas, a homebuilder, bought two residential lots on a South Carolina barrier island in 1986. He planned to build and sell two single-family houses similar to those on nearby lots. At the time he purchased the land, state law allowed house construction on the lots. In 1988 South Carolina passed the Beachfront Management Act to protect the state's beaches from erosion. Lucas's land fell within the area considered in danger of erosion; as a result, Lucas could no longer build the houses.

Lucas went to court, claiming that the Beachfront Management Act had taken his property without just compensation because it no longer had any value if he could not build there. Lucas did not question the right of the state of South Carolina to take his property for the common good. Rather, he claimed the state had to compensate him for the financial loss that resulted from the devaluing of the property.

The Supreme Court said that a state could stop a landowner from building on his or her property only if he or she was using it for a "harmful or noxious" purpose—for example, building a brickyard or a brewery in a residential area. This was not the case. Lucas had planned to build homes, a legitimate purpose that was neither harmful nor noxious. Although it was possible to define the planned buildings as harmful to South Carolina's ecological resources, this would not be consistent with earlier Court interpretations of "harmful." Only by showing that Lucas had intended to do something "harmful or noxious" with the land could the state take his land without compensation. This the state did not do, and, therefore, it owed him the money.

Invasive Species

People are not the only ones who have dramatically altered wetlands. Nonnative—also called exotic—species have been as devastating to wetlands as humans by changing the nature of the ecosystem, thereby interfering with its function and the survival of native plants and animals. Plants and animals introduced either accidentally or deliberately can cause unexpected harm by displacing native species from their habitat or by placing stress, such as disease or predation, on a native species.

In 1899 the coypu (Myocastor coypus ) was introduced into California for the fur-farming trade. This animal is a beaverlike aquatic South American rodent that is bred for its fur. This introduction was originally viewed as a way to provide economic benefit. Subsequently, state and federal agencies as well as private interests were responsible for introducing the coypu into the wild in fifteen states to provide a new fur resource. In coastal states such as Maryland and Louisiana, the results have been disastrous.

Coypu live in fresh, intermediate, and brackish marshes and wetlands and feed on the vegetation. They eat all the vegetation in an area, changing a marsh to a barren mudflat. Coypu feed on the base of plant stems and dig for roots and rhizomes in the winter. Their grazing strips large patches of marsh, and their digging turns over the upper peat layer. This conversion of marsh to open water destroys valuable habitat for muskrat, wading birds, amphibians, reptiles, ducks, fish, crabs, and a host of other species, as well as causing erosion and siltation.

Invasive plant species can be as harmful as invasive animal species. Eurasian watermilfoil, phragmites (common reed grass), hydrilla, and purple loosestrife are introduced species that have disrupted wetland systems. Purple loosestrife (Lythrum salicaria ) is a good example. It is a perennial herb with reddish-purple flowers that may reach six feet in height under the right conditions. It was an important medicinal herb and ornamental as early as two hundred years ago on the East Coast and was probably introduced for this reason. It has no known North American predators and has a high reproductive capacity—up to three hundred thousand seeds per stalk. Because it can outcompete most native wetland plants, it can change the character and ecological function of a marsh. This is a serious threat because many wetland and other wildlife species are adapted to and depend on specific plants.

LOSS AND GAIN IN WETLAND ACREAGE

When the first Europeans arrived in North America, Thomas E. Dahl and Gregory J. Allord indicate in History of Wetlands in the Coterminous United States (March 7, 1997, http://water.usgs.gov/nwsum/WSP2425/history.html) that there were an estimated 221 million acres of wetlands in the lower forty-eight states. In his 2006 report, Dahl notes that in 2004 there were an estimated 107.7 million acres. In the intervening years, more than 50% of the wetlands in the lower forty-eight states had been lost. Wetlands had been drained, dredged, filled, leveled, and flooded to meet human needs. Although natural forces such as erosion, sedimentation, and a rise or drop in sea level may erase wetlands over time, most wetland losses have been caused by humans. Many of the nation's older cities, such as New York City, Baltimore, Philadelphia, New Orleans, and Charleston, are built on filled wetlands.

However, Dahl mentions that after decades of wetland losses there was an annual gain of thirty-two thousand acres of wetlands from 1998 to 2004. (See Figure 7.8.) Additionally, the loss of wetland shrank from 458,000 acres in the 1950s and 1970s to 290,000 acres in the 1970s and 1980s, which is a decrease of 37%. By the 1980s and 1990s the annual wetland loss had declined to 58,500 acres, which is a 79% decrease from the 1970s and 1980s.

Dahl details the reasons for wetlands losses during the 1998–2004 period. Figure 7.9 shows that the highest acreage lost annually was because of urban development. Dahl determines that urban and rural development accounted for an estimated 61% of wetland losses. In addition, 70,100 acres of wetlands were estimated to have been lost to deepwater habitats. Deepwater habitats are "environments where surface water is permanent and often deep, so that water, rather than air, is the principal medium in which the dominant organisms live." Some wetlands (18,000 acres) were lost to silviculture, the planting of trees.

Dahl also discusses the reasons for wetland gains. (See Figure 7.9.) More than 70,000 acres of wetlands were gained from wetland restoration and conservation programs converting agricultural land to wetlands, and nearly 350,000 acres were gained from these programs converting other types of land, such as prairie, forest, or scrub land, to wetlands.

WETLAND PROTECTIVE LEGISLATION AND PROGRAMS

Since the early 1970s conservationists have turned to the courts to challenge reclamation projects and protect wetlands. If drainage once seemed to improve the look of the land, beginning in the 1970s it was more likely to be seen as degrading it. Wetlands turned out to be not wastelands, but systems efficient in harnessing the sun's rays to feed the food chain and play an important role in the global cycle of water, nitrogen, carbon, and sulfur.

As the drainage movement once found support in state laws and federal policies, so did the preservation movement. In 1977 President Jimmy Carter issued an executive order instructing federal agencies to minimize damage to wetlands. In 1989 the EPA adopted a goal of "no net loss" of wetlands, meaning that where a wetland is developed for other uses, the developer must create a wetland elsewhere to maintain an overall constant amount of wetland acreage.

Clean Water Act

Section 404 of the Federal Water Pollution Control Act of 1972 is commonly called the Clean Water Act (CWA). The goal of the CWA is to "restore and maintain the chemical, physical, and biological integrity of the nation's water." Wetlands are considered part of the nation's water and are covered by the CWA.

The CWA authorizes the Army Corps of Engineers to be the primary federal authority for the protection of wetlands. The Corps' jurisdiction encompasses all navigable waters of the United States, plus their tributaries and adjacent wetlands, and includes ocean waters within three nautical miles of the coastline and isolated waters where the use, degradation, or destruction of these waters could affect interstate commerce or foreign commerce. The Corps evaluates the impact of proposed projects that involve wetlands by considering comments from the EPA, the USFWS, the National Marine Fisheries Service, and the affected states. Regulations established under the CWA require that any project affecting more than one-third of an acre of wetlands or five hundred linear feet of streams must be approved by the Corps.

CWA JURISDICTION QUESTIONED

Between 2000 and 2002 legal challenges arose over the extent of the Corps' authority under Section 404 of the CWA and the meaning of certain terms used in the act (such as "waters of the United States" and "navigable waters"). In the CWA information brief The Supreme Court's SWANCC Decision (August 2003, http://homer.ornl.gov/nuclearsafety/nsea/oepa/guidance/cwa/swancc_info_brf.pdf), the U.S. Department of Energy details one such challenge.

According to the brief, the Solid Waste Agency of Northern Cook County (SWANCC) wanted to develop a nonhazardous solid waste disposal facility on a site that contained isolated ponds and wetlands. The Corps denied SWANCC a Section 404 permit to fill those wetlands because they were used by migratory birds. Lower courts found in favor of the Corps, and SWANCC appealed the finding to the U.S. Supreme Court.

On January 9, 2001, the Supreme Court issued the decision Solid Waste Agency of Northern Cook County v. United States Army Corps of Engineers (531 U.S. 159). The Court determined that the Corps' authority under the CWA did not extend to isolated wetlands if they were not "adjacent" to navigable waters. It held that the Corps exceeded its statutory authority by asserting CWA jurisdiction over the ponds that SWANCC wanted to fill based solely on the use of those "non-navigable, isolated, intrastate" waters by migratory birds.

PROPOSED CLEAN WATER AUTHORITY RESTORATION ACT

The 2001 SWANCC decision narrowed the scope of wetlands, streams, lakes, and other waters protected under the CWA, which has prompted a move to restore protection. The proposed Clean Water Authority Restoration Act (CWARA) would restore the broad scope of protection to these water bodies and reestablish protections for "isolated" wetlands throughout the United States. The most recent version of the bill was introduced in both the U.S. House of Representatives and the U.S. Senate in May 2005. In early 2007 the bill was in the first stages of the legislative process in both chambers of Congress, having been referred to subcommittees for consideration.

Farm Bill of 1996

The 1996 Farm Bill reauthorized the Conservation Reserve Program and created the Wetlands Reserve Program. The two programs are designed to protect and restore wetlands.

WETLANDS RESERVE PROGRAM

The Wetlands Reserve Program (WRP) is a voluntary USDA program and has been implemented in forty-nine states. The program provides farmers with financial incentives, such as a fair market price for land, to retire marginal farmland and, in many cases, to restore and protect wetlands. In the key points sheet "Farm Bill 2002" (September 2004, http://www.nrcs.usda.gov/programs/farmbill/2002/pdf/WRPKyPts.pdf), the USDA notes that the program had enrolled nearly 1.5 million acres in 2004. Retiring cropland through the WRP has benefited the recovery of threatened or endangered species and has protected wetlands. The WRP was reauthorized under the Farm Bill of 2002 and is to extend through December 31, 2007.

CONSERVATION RESERVE PROGRAM

The Conservation Reserve Program (CRP) was originally authorized in the Farm Bill of 1985 as a soil conservation strategy that included paying farmers to retire marginal cropland from production for ten years. Its political support came from its potential to reduce expensive crop surpluses. The Natural Resources Conservation Service notes in "Conservation Reserve Program" (March 26, 2007, http://www.nrcs.usda.gov/Programs/crp/) that under the CRP the Farm Service Agency pays farmers to plant natural vegetation in their "highly erodible cropland or other environmentally sensitive acreage."

Unlike the WRP, farmers do not have to permanently retire their land under this program, but instead can do so for ten-year intervals. As a wetland protection and restoration strategy, the program has been successful in terms of the thousands of acres of cropland that have been restored to a natural state, which in many cases includes wetlands. The CRP was reauthorized in the Farm Bill of 2002, extending the program through December 31, 2007.

State Wetland Protection Programs

Many states have enacted their own state laws to protect wetlands. These laws may complement or be more stringent than federal regulations. For example, Maryland has had state laws to protect tidal wetlands since the early 1970s. In 1989 Maryland adopted its Nontidal Wetlands Act to provide the same protections to freshwater wetlands.

Besides using their CWA authority, states have included wetland protection in their water quality standards, passed laws protecting ecologically important wetlands such as the Dismal Swamp in Virginia and North Carolina, established mitigation banking, and created public education programs to increase public awareness of the value of wetlands. Several states have set up special funds to buy important wetlands.

WETLAND GAINS

As shown in Figure 7.8, wetland gains have been made in recent years. Figure 7.9 shows the reasons for these gains. Many efforts are ongoing at the private, local, state, and federal levels to protect existing wetlands and to create new ones. Wetland losses can be offset by restoring, creating, enhancing, replacing, or reallocating wetlands:

• Wetland restoration—the return of a wetland to a close approximation of its condition before disturbance, including reestablishment of its predisturbance aquatic functions and related physical, chemical, and biological characteristics.
• Creation—the construction of a wetland in an area that was not a wetland within the past one hundred to two hundred years and is isolated from other wetlands.
• Enhancement—the modification of one or more structural features of an existing wetland to increase one or more functions based on management objectives. Enhancement, while causing a positive gain in one function, frequently results in a reduction in another function.
• Replacement or reallocation—activities in which most or all of an existing wetland is converted to a different type of wetland and has the same drawback as enhancement.

Each of these approaches has benefits and drawbacks.

Private Initiatives

Many of the wetland areas in the United States are privately owned. A number of government programs, both regulatory and voluntary, exist to foster wetland protection, and some foster both restoration and enhancement. Some of the most successful wetland programs and projects are the result of private initiatives. Frequently, private organizations form partnerships with landowners to buy, lease, or create easements paid for with private, or a mix of private and public, funds.

Organizations such as the Nature Conservancy, Ducks Unlimited (DU), the Audubon Society, the Chesapeake Bay Foundation, and hundreds of others are working with private landowners, corporations, local communities, volunteers, and federal and state agencies in innovative projects to protect and restore wetlands. For example, the Nature Conservancy oversees many wetland restoration projects, including two on the Illinois River—Spunky Bottoms (2007, http://www.nature.org/initiatives/freshwater/work/illinoisriver.html) and Emiquon (2007, http://www.nature.org/wherewework/northamerica/states/illinois/preserves/art1112.html)—that aim to return more than eighty-five hundred acres of farmed land to their original wetland state.

In another example, the DU is working with the National Resources Conservation Service to implement the WRP in the Mississippi Alluvial Valley, which according to the DU, in "Mississippi Alluvial Valley" (2007, http://www.ducks.org/conservation/initiative21.aspx), historically comprised 24.7 million acres of hardwood bottom stretching from southern Illinois to Louisiana. In "Conservation in Mississippi" (2007, http://www.ducks.org/Page1666.aspx), the DU reports that it is working to conserve over 250,000 acres of waterfowl habitat throughout Mississippi by restoring hydrology and planting bottomland hardwood seedlings.

Constructed Wetlands

Constructed wetlands are marshes that are built to filter contaminated water. They consist of soil and drainage materials (such as gravel), water, plants, and microorganisms. Using constructed wetlands for wastewater treatment is a simple, economical, and environmentally friendly method that is being used more frequently than in the past.

Constructed wetland treatment systems are designed and built to use the natural processes involving wetland soils, vegetation, and their associated microbes to help treat wastewater. They are designed to take advantage of many of the same processes that occur in wetlands but in a more controlled manner. Even though some of these systems are operated solely to treat wastewater, others are designed with the multiple objectives of using treated wastewater as a source of water for the creation or restoration of wetland habitat for wildlife and environmental enhancement. The primary drawback to constructed wetlands for wastewater treatment is that they are land intensive; large land tracts are not always available at affordable prices.

There are two general types of constructed wetland treatments: subsurface flow systems and free water surface systems. Both types are usually built in basins or channels with a natural or human-made subsurface barrier to limit seepage. The subsurface flow systems keep water flowing through soil, sand, gravel, or crushed rock underground to minimize odors and other related problems. (See Figure 7.10.) Subsurface flow systems are also known as rock-reed filters, vegetated submerged bed systems, and root-zone systems. Free water surface systems are designed to simulate natural wetlands, with the water flowing over the soil surface at shallow depths.

The EPA's Office of Water reports in Constructed Treatment Wetlands (August 2004, http://www.epa.gov/owow/wetlands/pdf/ConstructedW.pdf) that approximately five thousand constructed wetland treatment systems have been built in Europe and about one thousand are operating in the United States.

Marsh construction and wetland rehabilitation as a method of disposing of dredged materials are another growing source of wetland construction. The Army Corps of Engineers has been using dredged material to restore or construct marshes since 1969. Dredged material is placed on shallow bay bottoms to build up elevations to an intertidal level, usually by pumping dredged material to the marsh construction site. If the site is exposed to high wind or wave action, protective structures such as rock or concrete breakwaters are built. Vegetation can be planted or the site may be left to develop naturally. Generally, within two to three years, these sites are indistinguishable from natural wetlands in appearance.

Restoration of the Florida Everglades

The Everglades is a premier wetland in the United States. It is designated as an International Biosphere Reserve, a World Heritage Site, and a Wetland of International Importance. According to the World Heritage Committee, the Everglades is the only U.S. site on the List of World Heritage in Danger (April 10, 2007, http://whc.unesco.org/en/danger/). Figure 7.11 shows the location of the Everglades and how it has been reduced to about half its former size.

According to the South Florida Ecosystem Restoration Task Force (April 6, 2007, http://www.sfrestore.org/), the Everglades is part of the South Florida Ecosystem, an eighteen-thousand-square-mile region extending from the Kissimmee River near Orlando to the Florida Keys. Originally a wide expanse of wetland, pine forests, mangroves, coastal islands, and coral reefs, in the twenty-first century it is one of the nation's most highly populated and manipulated regions. Its freshwater supply comes from rainfall in the Kissimmee River Basin and southward, mostly in May through October.

Slow and rain driven, the natural cycle of freshwater circulation feeding the Everglades historically built up in shallow Lake Okeechobee, which averages twelve feet deep and covers about 730 square miles. Thus began the flow of the wide, shallow "river of grass," as it was called by Native Americans. Fifty miles wide in places, one to three feet deep in the slough's center, and only six inches deep elsewhere, it flowed south at a rate of about one hundred feet per day across the saw grass of the Everglades to the mangrove estuaries on the Gulf of Mexico. A six-month dry season followed this flow. During the dry season water levels gradually drop. The plants and animals of the Everglades are adapted to the alternating wet and dry seasons.

During the past one hundred years an elaborate system of dikes, canals, levees, floodgates, and pumps was built to move water to agricultural fields, urban areas, and the Everglades National Park. Water runoff from agriculture and urban development brought excess nutrients into the Everglades, reducing production of beneficial algae and promoting unnatural growth of other vegetation. Ill-timed human manipulation of the water supply interfered with the natural water cycle, ruining critical spawning, feeding, and nesting conditions for many species.

The Florida legislature has enacted a number of laws to combat the growing water shortage in Florida, including the Everglades. The 1981 Save Our Rivers Act and the 1990 Preservation 2000 Fund authorized the water management districts to buy property to protect water sources, groundwater recharge, and other natural resources. The South Florida Water Management District (SFWMD; 2007, http://www.evergladesplan.org/pm/progr_land_aquisition.cfm), an agency that oversees flood protection and water supply, began buying out landowners in the eastern Everglades area in hopes of retaking thousands of acres of agricultural and residential property at an estimated cost of $2.2 billion. The action is aimed at restoring water flow to Everglades National Park.

In 1998 the Army Corps of Engineers and the SFWMD released their plan for improving Florida's ecological and economic health: the Comprehensive Everglades Restoration Plan (CERP). This plan covers the entire region and its water problems and focuses on recovering the major characteristics that defined the "river of grass." Specifically, the plan calls for:

• Reducing the freshwater flows into the Caloosahatchee River and the St. Lucie Canal, thereby restoring to the Everglades water now lost to the tide.
• Returning the water flow in the Kissimmee River to its former floodplain to achieve a more meandering river system.
• Restoring forty thousand acres of marshes for water storage and filtration to remove nutrients before water entering the Everglades.
• Modifying water deliveries through improved timing and distribution to mimic historic water conditions.
• Reestablishing historic flows and water levels to sloughs feeding into Florida Bay to restore natural estuarine salinity.

The Water Resources Development Act of 2000 approved the CERP. The SFWMD (2007, http://www.ever gladesplan.org/about/about_cerp_brief.aspx) states that this plan will take more than thirty years to carry out and will cost an estimated $7.8 billion. The primary goal of the project is to restore critical water flows to the Everglades and ensure adequate water supplies for cities, communities, and farmers in southern Florida well into the future. The cost of the project will be shared equally between the state of Florida and the federal government.