Since the 1600s, more than half of the original wetlands in the lower 48 states have been destroyed. Wetlands have been drained and converted to farmland, filled for housing developments and industrial facilities, and used as receptacles for waste. Human activities continue to adversely affect wetland ecosystems. (NCSU)

More recently, society has begun to understand the functions of wetlands and the values humans obtain from them. Wetlands help regulate water levels within watersheds; improve water quality; reduce flood and storm damages; provid

Urbanization is a major cause of impairment of wetlands (USEPA 1994b). Urbanization has resulted in direct loss of wetland acreage as well as degradation of wetlands. Degradation is due to changes in water quality, quantity, and flow rates; increases in pollutant inputs; and changes in species composition as a result of introduction of non-native species and disturbance. The major pollutants associated with urbanization are sediment, nutrients, oxygen-demanding substances, road salts, heavy metals, hydrocarbons, bacteria, and viruses (USEPA 1994b). These pollutants may enter wetlands from point sources or from nonpoint sources. Construction activities are a major source of suspended sediments that enter wetlands through urban runoff. Toxic, radioactive, or acidic compounds and high concentrations of metals in abandoned industrial wastes at Superfund sites, or in operative (RCRA) waste sites, may be an ecological risk to wetlands fauna and flora. Clean-up activities at Superfund and RCRA sites can degrade adjacent wetlands as well through disturbance of hydrology, introduction of contaminants, and degradation of habitat by equipment. (Magistro and Lee 1988)

Scientists have estimated that wetlands may remove between 70% and 90% of entering nitrogen and riparian forests can reduce nitrogen concentrations in runoff and floodwater by up to 90% and phosphate concentrations by 50% (NCSU).

Nitrous oxides, sulfurous oxides, heavy metals, pesticides, and other organics and inorganics are released into the atmosphere by industrial and agricultural activities, and from vehicles . All of these compounds can enter wetlands through wet and dry atmospheric deposition and can adversely affect aquatic organisms and the terrestrial organisms that feed on them.

Riverine - All wetlands and deepwater habitats contained within a channel except

(hydrology) at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation (hydrophytes) typically adapted for life in saturated soil conditions (hydric soils). Wetlands generally include swamps, marshes, bogs, and similar areas (40 CFR 232.2(r)). Jurisdictional wetlands -- those that are regulated by the U.S. Army Corps of Engineers (Corps) under Section 404 -- must exhibit all three characteristics:

Some common words found in the essay are:
Mitsch Gosselink, Service Cowardin, FUNCTIONS VALUES, Urbanization Urbanization, United Inland, Security Act, LOSS DEGRADATION, Chesapeake Bay, Removal Metals, Water Act, surface water, ground water, water quality, mitsch gosselink 1993, fish wildlife, mitsch gosselink, gosselink 1993, water wetland, usepa 1994b, section 404, trees shrubs, precipitation surface water, emergents emergent mosses, coastal estuarine wetlands, wetlands deepwater habitats,
Approximate Word count = 3432
Approximate Pages = 14 (250 words per page double spaced)