FYI Even a net gain of 50,000 acres a year would require more than 40 years of sustained effort to replace only one percent of the nation's original wetland acreage. (Source: David Smith, "Comparing Apples to Oranges," National Wetlands Newsletter 19, no. 4 [July-August 1997]: 13.)

Wetlands can be located either near the coast (coastal wetlands) or farther inland (interior wetlands). Though less than five percent of the state's total area is wetlands, and an even smaller percentage is coastal wetlands, Texas has been identified as one of 19 states with significant coastal wetlands and significant coastal wetland losses.^*

Wetlands are defined in state law as areas that are inundated or saturated by surface or groundwater 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. The major wetland ecosystems of Texas include coastal marches and estuaries, forested scrub/shrub, tidal flats, bottomland hardwoods and the playa lakes, concentrated in the Panhandle. Coastal wetlands include salt, intermediate, brackish, and fresh marshes, tidal inlands, and forested scrub.

Coastal wetlands act as a natural filter for various natural and human-made contaminants, protecting the overall estuarine system. Coastal wetlands also help control excessive runoff to the bays and erosion of lands, protecting people and property from storms, floods, and erosions by serving as a buffer between land and water. The wetlands also provide important nutrients for the bay ecosystem, as well as essential habitat for many species of waterfowl, reptiles, mammals, fish, and other wildlife.

In addition to these benefits in habitat, water quality, flood control, and erosion control, coastal wetlands provide direct benefits to the Texas economy through commercial and sport fishing, hunting, nature tourism, and bird-watching. Shrimp, oysters, blue crab, black drum, and southern flounder either depend directly on habitat provided by wetlands for spawning and nursery grounds or receive important nutrients and food from fish and wildlife that depend on these wetlands. Finally, property values of developments near open spaces such as wetlands increase, resulting in higher tax revenues for local governments and schools.^*

Amount of Coastal Wetlands and Wetlands Loss in Texas

Estimating the amount of coastal wetlands and wetlands loss is unfortunately difficult because of differing definitions and climactic changes which impact their occurrence. Estimates of the amount of coastal wetlands loss in Texas vary by source. In 1965, the U.S. Fish and Wildlife Service estimated that Texas coastal marshes made up a total of 937,400 acres, while a 1991 NOAA Report -- using different definitions and methodologies --  estimated there were 6.4 million acres of inland wetlands -- mainly in riparian areas -- and 1.65 million acres of coastal wetlands, including 962,400 acres of coastal marshes, 410,000 acres of forested scrub and shrub and 275,000 acres of tidal flats.^* In a more recent 1997 study, scientists from the U.S. Fish and Wildlife Service—in cooperation with other federal and state agencies and again using different definitions—estimated that 4.1 million acres of coastal wetlands existed in the mid-1950s in a 20,000 square mile "coastal" area. By 1992, the study estimated that Texas had 3.9 million square acres of coastal wetlands, including 3.3 million acres of freshwater wetlands and 567,000 acres of saltwater wetlands.^*

The study did not define the quality of wetlands, but simply the number of acres they cover. Thus, while the total amount of coastal wetlands witnessed a relatively small decline in the past forty years, the type and quality of wetlands has changed dramatically. For example, about 52 percent of the coastal freshwater wetlands were used for farmlands—mainly rice farming—in 1992, compared to 47 percent in 1955. Saltwater intrusion caused by canals, land subsidence (sinking), and drainage ditches has severely damaged some of the remaining wetlands.^*

Other recent studies have catalogued destruction of wetlands in individual areas. A 1993 study of the Galveston Bay system showed an estimated net loss of 33,400 acres -- about 19 percent of all wetlands -- between 1953 and 1989.^* Still another study published in 2002 examined the status and trends of wetlands on the Texas Barrier Islands, Matagorda Bay and San Antonio Bay within Matagorda and Calhoun Counties using color infrared photographs taken in 2001 and 1979 and black-and-white  photographs taken in the 1950s. The regional study found over 45,000 acres of coastal wetlands, dominated by saltwater marshes and seagrass beds. The study actually found that the amount of saltwater marshes and seabed grasses actually increased over the time period -- albeit slightly -- but there was a major decline in the total area of tidal flats between the 1950s and 2001 -- declining from roughly 10,000 to 5650 acres over the period -- as well as major declines in freshwater marshes and Gulf beaches. For example, on Matagorda Island, tidal flats declined from some 5,500 acres in the 1950s to some 2,250 acres by 2001, much of which can be explained by a rising sea level, a trend also reported on Mustang Island and San Jose Island.^*

In the United States as a whole, an estimated 58,500 acres of wetlands—both coastal and interior—are lost each year.^* This includes both wetlands lost as a result of draining and filling projects requiring Army Corps of Engineers Section 404 permits and estimated loss from other sources not requiring such permits. In fact, about 80 percent of lost wetlands in the United States are not reported to the Corps of Engineers.^* And the amount of wetlands lost without any reporting to the U.S. Army Corps of Engineers is likely increasing, due to the January 2001 Supreme Court ruling which held that "isolated" wetlands not connected to streams, rivers and bays are not afforded protection under the Clean Water Act. The ruling has led to differing interpretations of what constitutes an "isolated" wetlands. In Texas, the Galveston District of the Army Corps of Engineers has been interpreting the ruling broadly, meaning that those wishing to fill and dredge wetlands along the coast which are only connected to waterways through flooding and overland flow during precipitation do not require a permit -- or mitigation -- to do so.^* The EPA and Army Corps of Engineers have proposed new rules on the Section 404 Permit process based upon the Supreme Court decision, although it may be several years until the rules are in place. In the meantime, filling or dredging many Texas coastal "isolated" marshes will in many cases not require a special permit.

Despite the continued loss of wetlands overall, net loss of wetlands in the United States has been reduced in recent years. The biggest reason for the decline is the reduction in the amount of wetlands utilized for agriculture. Areas such as the Northern and Southern Plains actually experienced a net gain of wetlands between 1982 and 1992, according to National Resources Inventory, a program under the Natural Resources Conservation Service (NRCS) of the U.S. Department of Agriculture (USDA).^* In addition, both volunteer mitigation programs run by the U.S. Fish and Wildlife Service, as well as mitigation requirements under the Army Corps of Engineers Section 404 program, have actually offset losses in some years. Both the 1985 Food Security Act, and the 1996 and 2001 Farm Bills provided incentives to farmers to conserve and protect wetlands.

ESTIMATED LOSS OF WETLANDS BY SOURCE IN GALVESTON BAY CAUSE TYPE OF WETLAND AFFECTED NET LOSS, 1950–1990 (ACRES) Subsidence and sea level rises (aquifer overpumping) Estuarine bay marshes 24,600 Conversion to urban and agricultural use Freshwater marshes 35,600 Dredge and fill activities Estuarine bay marshes 7,070 Modifications of shoreline (flood control, salt water barriers, cooling ponds) Estuarine bay marshes 6,300 Source: Galveston Bay National Estuary Program, Galveston Bay Environmental Characterization Report (Houston: Galveston Bay National Estuary Program, 1993), 218.

Several efforts are underway in the state to better map and protect coastal wetlands. In 1994, five Texas state agencies and four federal agencies began a web-based system to share information over the internet. Today, the Texas Wetland Information Network (WetNet) has begun to provide information about wetlands to internet users.^* In addition, the state has been digitizing the U.S. Fish and Wildlife's National Wetlands Inventory Program's maps and aerial photographs to better map and monitor changes in the state's wetlands. The TPWD plans to classify the entire Texas coastal zone and determine wetlands change in five-year periods.^*

CAUSES OF COASTAL WETLAND LOSS Direct Causes Drainage for crop production, timber production, and mosquito control. Dredging and stream channelization for navigation channels, flood protection, coastal housing development, and reservoir maintenance. Filling by dredged material and other solid waste disposal, roads and highways, and urban development. Construction of dikes, dams, levees, and seawalls for flood control, water supply, irrigation, and storm protection. Discharge of materials into waters and wetlands. Mining of wetlands soils for peat, coal, sand, gravel, phosphate, and other materials. Indirect Causes Subsidence due to extraction of groundater, oil and gas, sulfur, and other materials. Hydrological alterations by canals, spoil banks, roads, and groundwater withdrawals. Sediment diversion by dams, deep channels, and other structures. Natural Causes Subsidence (including natural rise of sea level) Droughts Hurricanes Erosion Muskrat, nutria, grasscarp, and goose "eat outs" Source: Tom Calnan, Comprehensive Strategies for Protecting Coastal Wetlands (Austin: Texas General Land Office, 1994).

Threats to Wetlands

Like estuaries, wetlands are subject to a variety of threats. Subsidence of land along the coast and the loss of coastline caused by soil erosion and a rising sea level have contributed to the loss of coastal wetlands. Each year, 225 acres of gulf shoreline wash into the sea. An estimated 21,000 acres of shoreline were lost between the mid-1800s and 1982.^* In some areas of Texas, overpumping of groundwater has led to subsidence of the land. This impact alone has led to the loss of an estimated 24,600 acres of marshes since the 1950s in the four-county Galveston Bay area.^* The U.S. Fish and Wildlife Service reports a loss of 20,000 acres of coastal marshes to open bays from land subsidence due to extraction of oil, gas, and water.^*

Another significant cause of coastal wetlands loss is conversion of wetlands for urban or agricultural development. Wetlands are sometimes drained and turned into rangeland or cropland or fitted for urban use, in part to keep up with population growth. They are sometimes impacted by dredging and filling operations, conducted mainly to widen canals such as the Gulf Intracoastal Waterway for navigation purposes, because dredged soil is often deposited in the wetlands' open water sites. Construction of roads and levees can also alter the original tidal hydrological characteristics.

One dramatic example of wetlands destruction resulting from land-use changes has been the loss of shoal grass in the Lower Laguna Madre. Between 1965 and 1998, there was an estimated 60 percent reduction in shoal grass beds in this water body. Studies attribute the loss of sea grasses to suspension of fine-particle sediment caused by the dredging of the Gulf Intracoastal Waterway.^*

CHANGES IN SEA GRASSES OF THE LAGUNA MADRE, 1965-1988 Note: South Bay was not sampled in 1965. 1965 Seagrass data were not available for all portions of Upper Laguna Madre. Source: Compiled by Doug Houston, Texas General Land Office, Resource Management/Coastal Division. Adapted from M. L. Quammen and C. P. Onuf, "Laguna Madre: Seagrass Changes Continue Decades After Salinity Reduction," Estuaries (June 16, 1993), 304.

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