As defined for both Commonwealth and Federal regulatory purposes, wetlands are:

Those areas that are inundated or saturated by surface water 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, including swamps, marshes, bogs, and similar areas. [25 Pa. Code 105.1; 33 CFR 328.3; 40 CFR 230.3]

A wetland is land that is transitional in nature between uplands and open water, and it shares characteristics common to both. In practice, three parameters are used to recognize areas eligible for regulation as wetland: soil, vegetation, and hydrology. As the name implies, wetlands typically are wet, usually for some extended period of time each year. Prolonged wetness may result from inundation or saturation associated with surface water or groundwater.

Wetlands are wetter than adjacent uplands because they receive more water, either because the topography traps precipitation and runoff, subsurface conditions prevent water from seeping down into the soil, groundwater reaches the surface to form springs or seeps, or these factors occur in some combination. Some wetlands may be wet year-round; other wetlands may be wet only seasonally, and thus dry for some part of the year. When wetland hydrology is seasonally absent, the wetland nature of an area may not be obvious to the casual observer.

Although water is an essential feature, a wetland is unlike a pond, lake, or river in that it is not permanently covered by water so deep that rooted plants cannot grow in it. A wetland must have "hydrophytic vegetation," that is, plants peculiarly adapted to tolerate oxygen-poor, wet substrate conditions. A wetland also must have "hydric soil," which is soil that formed when oxygen was lacking as a result of prolonged inundation or saturation.
 

All three parameters (water, hydrophytic plants, and hydric soil) must be present for an area to be regulated as a wetland. The Army Corps of Engineers Wetland Delineation Manual (USA-EL 1987) specifies the technical procedures to be used to recognize and delineate wetlands subject to both Federal and Pennsylvania regulatory jurisdictions. Regulated wetlands must be identified case by case on each property subject to mining or other construction activity.

Although scarce, wetlands are among the most productive natural ecosystems in the world, providing many benefits to people and to society as a whole.

The National Wetlands Inventory (NWI) is a nationwide resource map atlas of wetlands and other waters prepared by the US Fish & Wildlife Service (USFWS) using the categories of Cowardin et al. (1979). NWI mapping is based on the laboratory interpretation of high altitude, vertical aerial photographs. Although limited ground-truthing was employed, the NWI did not rely on detailed field investigations. As a result, NWI maps typically understate the actual extent of wetlands (Stolt and Baker 1995; Klemow et al. 1999). NWI maps are not intended to be used for regulatory purposes, but rather as one source of information in preparation for a formal field delineation (USA-EL 1987).

Whether large or small, bodies of open water such as lakes, farm ponds, and other artificial impoundments are easily recognized on aerial photographs and thus on NWI maps. Also, emergent wetlands are generally identified, as well as the larger forested wetlands along floodplains. In contrast, small areas of forested wetlands away from streams are seldom identified on NWI maps in Pennsylvania, despite their ecological significance. Like the streams in this region, few wetlands of any kind have been inventoried biologically in southwestern Pennsylvania.

Wetlands are scarce features in Pennsylvania, where they have been reported to represent just over 1% of the total land area (Tiner 1990). Wetlands are particularly scarce in the unglaciated southwestern section of the Commonwealth where most Pennsylvania coal is mined today. Nowhere in Washington or Greene Counties are there wetlands to rival the expanse of Conneaut Marsh or the ubiquitous swampy depressions of the Poconos. Only a few of the larger, more conspicuous wetlands have been identified on available maps. To identify wetlands here requires careful fieldwork. Yet wetlands in southwestern Pennsylvania perform all the vital functions that they do everywhere else.

Fewer than 2,000 acres of vegetated wetlands were mapped by the NWI in Washington and Greene Counties combined, representing only about 0.2% of the land area (Figure 4). The largest wetlands in the region are encountered along the floodplains of streams. Other wetlands are found in depressions outside floodplains or around seeps and springs along or at the bottom of hillsides.

Although scarce, wetlands provide many benefits to people and to society as a whole. Some wetlands protect property from floodwaters by stabilizing stream banks or shorelines or by providing areas where excess water can be temporarily stored and then gradually released. Many wetlands located along streams can trap the sediments and pollutants in runoff before they can get into the waterways. Some wetlands provide recharge for groundwater; others contribute to the baseflow of streams. Not every wetland will necessarily provide every potential function. In general, however, wetlands are critical to the health of any region's streams, groundwater, and wildlife.

Vegetated wetlands are among the most productive natural ecosystems in the world (Tiner 1987). The high level of biological activity associated with the often complex structure of their vegetation allows wetlands to retain or recycle nutrients and to perform other water-purifying functions. Some wetlands provide important aesthetic, educational, or recreational values for trapping, hunting, fishing, nature observation, and scientific study.

Wetlands provide habitat for an impressive diversity of plants and animals, including many which are considered rare or endangered. According to the PADEP (1997a), 32 of the 38 species of amphibians in Pennsylvania (84%) spend a majority of their time in wetlands. Twenty-five percent of all reptiles in the Commonwealth (11 of 41 species) spend nearly 99% of their life in wetlands. About 122 species of shore and wading birds, waterfowl, and some song birds perform most of their activities in, on, or around wetlands. Some game birds, such as turkey, depend on wetlands especially in the winter. Mammals associated with wetlands include muskrat, otter, and beaver. Of the more than 650 kinds of plants deemed rare, threatened, or endangered in Pennsylvania, 75% are hydrophytes (Schmid & Kartesz 1994).

For three hundred years wetlands were not treasured as natural resources in the United States (Vileisis 1997, Schmid 2000). Only as a result of an increased understanding of the functions of wetlands and a recognition of their values for flood protection, water quality maintenance, fish and wildlife habitat, aesthetic, recreational, and other uses, have wetlands been afforded special protection nationally and in Pennsylvania, at least on paper, for the past two decades.

The importance of wetlands for water quality protection and purification is exemplified in the fact that use of constructed wetlands is one of the more popular, long-term methods of treating acid mine drainage (AMD). The physical characteristics of wetlands and the biochemical processes that occur in them provide a natural and effective way to aid in the removal of metals and the amelioration of AMD. According to staff at the PADEP Bureau of Abandoned Mine Reclamation (BAMR), 16 projects undertaken in Pennsylvania in the past three years are using constructed wetlands to treat AMD. Indeed, almost all AMD-treatment systems currently being funded by BAMR utilize constructed wetlands in some phase or aspect of the treatment process.

Longwall mining today is a major threat to natural wetlands. Hempel (1998) reported from his examination of internal studies from several Consolidation Coal Company mines that about 60% of all springs, ponds, and wells are permanently dewatered or degraded by longwall mining. Those water bodies get most of the protection offered by mining regulators; the percentage of damaged wetlands can be presumed to be at least as high, given the virtual absence of any effort to identify or regulate wetland resources.

RETURN TO PREVIOUS SECTION                               INDEX                                    NEXT