Skip to main content

About this book

The early 1990's marked an environmental watershed for our countly. Under two federal administrations significant environmental legislative, regulatOly and institutional changes took place which affected our Nation's wetland resources. Injust a few years, we have seen rapid evolution in the way in which we view wetlands with more emphasis on specific wetland types and the geographic provinces in which they occur. This Southern Appalachian Man and the Biosphere (SAMAB) conference on "Wetland Ecology, Management and Conservation" represents just one example of our desire to understand wetlands in non-coastal regions of the southern United States. The backdrop to this conference was one where the government, universities, and private sector have come together to create a broader and more sophisticated understanding of environmental stewardship for our water resources, especially wetlands. Although enforcement of environmental legislation by federal and state government agencies - limited by manpower shortages, budgetary constraints and undermined by weak enforcement - remains strong as measured by world standards; the realization that environmental degradation of wetlands is likely to get much worse necessitates a greater commitment and increased resource allocation for wetland protection and management. These contiIUled pressures on the wetland resource will create substantial opportunities for the application of environmentally-sound technologies and interdisciplinmy modeling teams to keep abreast of the factors influencing wetland integrity and function in the last half of the 1990's.

Table of Contents


Conference Summary Statement


Wetlands of the Interior Southeastern United States: Conference Summary Statement

The wetland resources in the southern United States are diverse, being characterized by bottomland hardwoods, forested riparian zones, swamps, marshes, bogs, and fens. Recognizing the importance of the wetland resource, the need to develop information on the diversity of wetland types, and the evolving public debate regarding the protection and management of wetlands, this conference was organized to (1) provide a forum for the presentation and discussion of current research and information on wetland ecosystems, (2) to develop a basis on which to improve wetland conservation and management, (3) to provide a forum to encourage collaboration in the study and management of wetland resources, and (4) to suggest actions that would benefit wetland conservation and management. Twenty-three invited technical papers and three working group sessions addressed topics encompassing the full spectrum of wetland issues, including resource status, ecological and hydrological processes, management and conservation, and restoration and creation. Major findings discussed at the conference included the need to distinguish between functions and values, the development of a hydrogeomorphic classification system for assessing wetland functions, and assessment methodologies for planning and implementing effective wetland restoration projects. Papers summarizing the current understanding of wetland soil and vegetation processes in the region highlighted the important role wetlands play in landscape function, yet the understanding of those processes is incomplete. Insights developed from the study of wetlands in the interior southeastern United States have widespread applicability to other regions because of similarities in hydrogeomorphic setting and vegetation communities, and the management and conservation issues.
C. C. Trettin, W. M. Aust, M. M. Davis, A. S. Weakley, J. Wisniewski

Wetland Resources


Classification and Inventory of Wetlands in the Southern Appalachian Region

The National Wetlands Inventory of the U.S. Fish and Wildlife Service has prepared large scale (1:24,000) wetland maps for nearly all of the Southern Appalachian Region. Traditional and digital cartographic products are available from the Earth Science Information Centers of the United States Geological Survey and from State-run distribution outlets. Most of the materials prepared by the NWI within the region were cooperatively funded by the States and other Federal Agencies.
NWI maps describe wetlands in terms of the life form of the dominant vegetation, substrata where vegetation is sparse or lacking, water chemistry, relative duration of inundation or saturation, and special modifiers. The maps display wetland polygons as small as 0.5 hectares in size and linear wetlands as narrow as 8 meters, showing the size, type of wetland, and relative position of the wetland on the landscape. The wetland inventory process is principally a remote sensing task, relying on the interpretation of high altitude color infrared aerial photography, supported with ground truth data and collateral information. The procedure has limitations related to scale, quality, and timing of the aerial photography; experience and training of the photo interpreters; and the wetland types which are to be classified and delineated. Since wetland maps provide a static depiction of a dynamic resource, the NWI conducts periodic wetland status and trends studies to evaluate wetland change in areal extent and the reasons for the change. Although trend surveys are routinely conducted nationally and selectively for regional and local areas, no study to specifically address the wetlands of the Southern Appalachian Region has been developed.
John M. Hefner, Charles G. Storrs

Identification of Wetlands in the Southern Appalachian Region and the Certification of Wetland Delineators

According to the Corps of Engineers Wetlands Delineation Manual, wetlands are identified by the presence of field indicators of hydrophytic vegetation, hydric soils, and wetland hydrology. In the southern Appalachian region, situations that present problems for wetland delineators include (1) wetlands developed on recently deposited alluvial soils that may show little evidence of hydric conditions, (2) areas occupied by FAC-dominated plant communities, (3) wetlands affected by past or present drainage practices, (4) man-induced wetlands that may lack certain wetland field indicators, and (5) hydric soil units that are too small or narrow to be delineated separately on soil survey map sheets. In March 1993, under direction of Section 307(e) of the Water Resources Development Act of 1990, the Corps of Engineers initiated a Wetland Delineator Certification Program. A 1-year demonstration program has recently ended in Maryland, Florida, and Washington, with nationwide implementation scheduled for later in 1994. This voluntary program is designed to increase the quality of wetland delineations submitted with Section 404 permit applications, and reduce processing time by reducing the need for extensive field verification of wetland boundaries.
James S. Wakeley

Biogeochemical Processes


Hillslope Nutrient Flux During Near-Stream Vegetation Removal I. A Multi-Scaled Modeling Design

At the Coweeta Hydrologic Laboratory in the southern Appalachians of western North Carolina, a near-stream vegetation manipulation experiment is being conducted to determine the effect of removal of streamside Rhododendron maximum L. on the export of hillslope nutrients (K, Na, Ca, Mg, N, P, S) and organic matter. Experimental hillslope transects that span topographical flowpaths from a local highpoint to the stream have been instrumented with lysimeters and TDR rods at two depths, as well as with streambed and streambank piezometers. We present a review of studies of nutrient flux in the riparian zone of forested watersheds. In the southern Appalachians, we hypothesize that R. maximum is a keystone species at the interface between terrestrial and aquatic systems, with extensive near-stream thickets having a possible impact on carbon and nutrient transport into streams. We present the conceptual basis and initial implementation of a model-based experimental design to test the effect of R. maximum removal on hillslope nutrient and organic matter export in upland watersheds. The model is terrain-based and will be used to extrapolate elemental flux measurements both spatially from the hillslope to watershed scale and temporally for various climate regimes. The model consists of three modules: (1) objective terrain analysis (TAPES-C); (2) a dynamic interception canopy module; (3) a hillslope hydrology module (IHDM4) with a 2-D Richard’s equation of subsurface moisture dynamics. Calibration and validation of the model will occur at two scales: at the hillslope scale, using well, lysimeter, and TDR data; at the watershed scale, using streamflow measurements across a variety of storm types. We show watershed terrain analysis for the experimental watershed (WS56) and discuss use of the model for understanding effects of watershed management of riparian zone processes.
J. A. Yeakley, J. L. Meyer, W. T. Swank

Plant Community Composition and Surface Water Chemistry of Fen Peatlands in West Virginia’s Appalachian Plateau

I analyzed plant community composition, surface water chemistry, soil saturation, landscape position, and disturbance history in 4 small peatlands in WV’s Allegheny Plateau, to determine vegetational differences among communities and identify environmental variables associated with community patterning. Thirty-four plant communites were identified, representing 5 physiognomic types: forest, tall and low shrub, herbaceous, and bryophyte. Of 138 species, only 34 were common to all sites; 56 were unique to single sites. Principal components analysis identified a major physiognomic separation between forest and tall shrub communities with less acid surface waters (pH 4.6 – 5.0) dominated by base cations (Ca++, Mg++, Na+, K+), vs. low shrub and bryophyte communities with more acidic surface waters (pH 4.0 – 4.4). Much of the variation in community composition resulted from changes in the distributions of Hypericum densiflorum, Rubus hispidus, Polytrichum commune, and Sphagnum fallax, with changes in soil saturation. Community distribution reflected an underlying pattern of basin geomorphology modified by beaver disturbance.
Mark R. Walbridge

Carbon Dynamics in Appalachian Peatlands of West Virginia and Western Maryland

Abundant production of organic matter that decomposes slowly under anaerobic conditions can result in substantial accumulation of soil organic matter in wetlands. Tedious means for estimating production and decomposition of plant material, especially roots, hampers our understanding of organic matter dynamics in such systems. In this paper, I describe a study that amended typical estimates for both production and decomposition of organic matter by measuring net flux of carbon dioxide (CO2) over the peat surface within a conifer swamp, a sedge-dominated marsh, and a bog in the Appalachian Mountain region of West Virginia and western Maryland, USA. The sites are relatively productive, with net primary production (NPP) of 30 to 82.5 mol C m-2 yr-1, but peat deposits are shallow with an average depth of about 1 m. In summer, all three sites showed net CO2 flux from the atmosphere to the peat during the daytime (-20.0 to -30.5 mmol m-2 d-1), supported by net photosynthesis, which was less than net CO2 flux from the peat into the atmosphere at nighttime (39.2 to 84.5 mmol m-2 d-1), supported by ecosystem respiration. The imbalance between these estimates suggests a net loss of carbon (C) from these ecosystems. The positive net CO2 flux seems to be so high because organic matter decomposition occurs throughout the peat deposit — and as a result concentrations of dissolved inorganic carbon (DIC) in peat pore waters reached 4,000 µmol L-1 by late November, and concentrations of dissolved organic carbon (DOC) in peat pore waters reached 12,000 µmol L-1. Comparing different approaches revealed several features of organic matter dynamics: (i) peat accretion in the top 30 cm of the peat deposit results in a C accumulation rate of about 15 mmol m-2 d-1; however, (ii) the entire peat deposit has a negative C balance losing about 20 mmol m-2 d-1.
J. B. Yavitt

Vegetation Dynamics and Ecology


Hydrologic and Wetland Characteristics of a Piedmont Bottom in South Carolina

A four hectare mixed bottomland hardwood site on Ninety Six Creek in the Piedmont of South Carolina near Ninety Six, SC was studied for two years to characterize wetland traits. The soils were thermic Fluventic or Fluvaquentic Dystrochrepts predominantly Shellbluff series and well drained. Overbank flooding occurred on the average of 4 times per year and 1.5 times during the growing season for a 13 year period. High water table levels during the early growing season were related to rainfall events. A hydrologic model (WATRCOM-2D), soils, water table levels, and GIS techniques were used to estimate the portion of the bottom that met wetland criteria similar to those defined in the 1987 and 1989 federal wetland delineation manuals. Less than one hectare met these criteria. The wetland “status” of the vegetation within the bottom and adjacent slope was not correlated with water table levels, predicted wetland areas, or landforms. Wetland traits of the site were closely related to hydric soil traits within the upper 25 cm of the Chewacla and Chenneby soils and landform characteristics. Wetlands in this bottom were primarily driven by local precipitation and not by overbank flooding as originally suspected. Songbirds and small mammals were relatively abundant in the small bottom during the spring and summer of 1992. Protection of only the jurisdictional wetlands in this bottom would not be adequate to sustain riverine functions (conveyor) and to provide wildlife travel corridors between adjacent forested areas.
D. D. Hook, W. H. McKee, T. M. Williams, S. Jones, D. Van Blaricom, J. Parsons

Landscape-Level Processes and Wetland Conservation in the Southern Appalachian Mountains

The function of wetland ecosystems is not independent of the landscape in which they are embedded. They have strong physical and biotic linkages to the surrounding landscape. Therefore, incorporating a broad-scale perspective in our study of wetland ecology will promote our understanding of these habitats in the Southern Appalachians. Changes in the surrounding landscape will likely affect wetlands. Broad-scale changes that are likely to affect wetlands include: 1) climate change, 2) land use and land cover change, 3) water and air-borne pollution, 4) a shift in disturbance/recovery regimes, and 5) habitat loss and fragmentation. Changes in climate and land cover can affect the hydrology of the landscape and, therefore, the water balance of wetlands. Excessive nutrients and toxin transported by air and water to wetlands can disrupt natural patterns of nutrient cycling. Periodic disturbances, like flooding in riparian zones, is required to maintain some wetlands. A change in disturbance regimes, such as an increase in fire frequency, could alter species composition and nutrient cycles in certain wetlands. Many plant and animal species that found in small, isolated wetlands have populations that are dependent on complementary habitats found in the surrounding landscape. Loss or fragmentation of these complementary habitats could result in the collapse of wetland populations.
Scott M. Pearson

Vegetation of Three High Elevation Southern Appalachian Bogs and Implications of Their Vegetational History

In order to investigate the extent of vegetation change during the Pleistocene Period, a study of three high elevation southern Appalachian bogs was undertaken. Three North Carolina sites were chosen that were suitable for pollen and paleoecological analysis: Flat Laurel Gap bog near Pisgah Mountain south of Asheville (elevation 1500 m), Boone Fork bog near Blowing Rock (elevation 1450 m).
Existing vegetation was sampled by transects of 10 x 10 m plot relevés that crossed a section of forest and open bog areas. While each site included a characteristic southern Appalachian bog, each differed: Flat Laurel Gap is predominately a heath community with interfingerings of open grassy glades which grade into a mixture of northern hardwoods and spruce; Boone Fork bog is a disturbed mixture of northern hardwoods which grades into a mixture of scattered shrubs and open glades predominated by Sphagnum; and Long Hope Menyanthes bog is an open herbaceous and grassy glade with scattered shrubs which grades abruptly into northern hardwoods and old-growth spruce. As might be expected, the more northern Long Hope Valley site had more northern taxa, such as Menyanthes trifoliata, Lonicera canadensis, and Vaccinium macrocarpon. The southern site also had a few boreal taxa such as Eriophorum virginicum.
Perhaps the best interpretation for these long-established southern Appalachian bogs is that they have provided continuously suitable habitats for relict northern species since the peak of the glacial ice advance 18,000 years ago.
J. Dan Pittillo

Wildlife Use of Southern Appalachian Wetlands in North Carolina

Wetlands provide structurally diverse habitats attractive to varied wildlife, both generalist and wetland specialist species. Wetlands in western North Carolina occupy a minor portion of the landscape, yet provide essential habitat for rare wildlife species. Structural features of western North Carolina wetlands that influence wildlife occurrence include meadows interspersed with shrub thickets, snags and hollow trees, fallen logs, deep mud and rivulets, and pools. Species lists keyed to structural features are presented.
A. C. Boynton

Non-Alluvial Wetlands of the Southern Blue Ridge — Diversity in a Threatened Ecosystem

The generally steep landscape of the Southern Blue Ridge is not conducive to the formation of extensive wetlands, but wetlands do occur. Wetlands in this region are mostly small in size ( < 10 ha), and are found in locations where topography is unusually gentle or where seepage is unusually strong or constant. Despite their rarity and small size, such wetlands show great species and community diversity, and are one of the most important habitats for rare (endemic and disjunct) plants and animals in the region. Community species composition seems to vary primarily in relation to elevation, topographic position, hydrology, underlying bedrock composition, recent land use, and biogeographic history. Based on differences in vegetation structure and composition, landscape position, and hydrology, we recognize nine groups of non-alluvial wetlands in the Southern Blue Ridge. An inventory of non-alluvial wetlands in the mountains of North Carolina revealed that the majority of these naturally rare communities are now destroyed or severely altered. Bogs and fens of the North Carolina mountains have been reduced nearly six-fold from an original extent of about 2000 ha, so that only about 300 ha remain in reasonably intact condition, and most of the remnants are compromised by hydrologic alteration and nutrient inputs. Because wetlands tend to be concentrated in valley bottoms and at low elevations where most land is privately owned, efforts to assure their long-term viability will require innovative protection and restoration tools.
A. S. Weakley, M. P. Schafale

Rare and Endangered Plants and Animals of Southern Appalachian Wetlands

At least one-third of the threatened and endangered species of the United States live in wetlands. Southern Appalachian bogs and fens, in particular, support a wealth of rare and unique life forms, many of which are found in no other habitat type. In North Carolina alone, nonalluvial mountain wetlands provide habitat for nearly 90 species of plants and animals that are considered rare, threatened, or endangered by the North Carolina Plant Conservation Program, the North Carolina Natural Heritage Program, the North Carolina Wildlife Resources Commission, or the U.S. Fish and Wildlife Service. These species include the bog turtle, mountain sweet pitcher plant, green pitcher plant, swamp pink, bunched arrowhead, and Gray’s lily, all of which are either on the federal list of endangered and threatened species or under consideration for that list. Mountain wetland habitats for these species are being destroyed and degraded at an accelerating rate for highway construction and expansion and residential and recreational development, as well as for industrial and agricultural uses.
Nora A. Murdock

Managed Wetlands


Riparian Forest Buffer System Research at the Coastal Plain Experiment Station, Tifton, GA

Recent attention has focused on riparian forest buffer systems for filtering sediment, nutrients, and pesticides entering from upslope agricultural fields. Studies in a variety of physiographic areas have shown that concentrations of sediment and agrichemicals are reduced after passage through a riparian forest. The mechanisms involved are both physical and biological, including deposition, uptake by vegetation, and loss by microbiological processes such as denitrification. Current research by USDA-ARS and University of Georgia scientists at Tifton, GA is focusing on managing riparian forest buffer systems to alleviate agricultural impacts on the environment. The underlying concept for this research is that agricultural impact on streams is best protected by a riparian forest buffer system consisting of three zones. In consecutive upslope order from the stream these zones are (1) a narrow band of permanent trees (5–10 m wide) immediately adjacent to the stream channel which provides streambank stabilization, organic debris input to streams, and shading of streams, (2) a forest management zone where maximum biomass production is stressed and trees can be harvested, and (3) a grass buffer strip up to 10 m wide to provide control of coarse sediment and to spread overland flow. Several ongoing projects at Tifton, GA are focusing on using riparian forest buffer systems as filters. A forest management project is testing the effects of different management practices on surface and ground water quality. This project includes three different forest management practices: mature forest, selectively thinned forest, and clearcut. In a different study a natural wetland is being restored by planting trees. The effectiveness of this wetland on filtering nutrients from dairy wastes which are being applied upslope is being evaluated. At this same site, a pesticide study is being conducted on the side opposite to where dairy wastes are applied. An overland flow-riparian buffer system using swine lagoon waste is evaluating the effectiveness of different vegetative treatments and lengths of buffer zones on filtering of nutrients. In this study three vegetative treatments are compared: (1) 10 m grass buffer and 20 m riparian forest, (2) 20 m grass buffer and 10 m riparian forest, (3) 10 m grass buffer and 20 m of the recommended wetland species maidencane. Waste is applied at the upper end of each plot at either a high or low rate, and then allowed to flow downslope. The three zone riparian forest buffer system is being used for the Riparian Ecosystem Management Model (REMM). This model, which is currently under development at Tifton, GA, is a computer simulation model designed to reduce soil and water degradation by aiding farmers and land use managers in decision making regarding how best to utilize their riparian buffer system. Both information currently being collected in field studies and development of the REMM are innovative farm-level and forestry technologies to protect soil and water resources.
R. K. Hubbard, R. R. Lowrance

Rapid Wetland Functional Assessment: Its Role and Utility in the Regulatory Arena

Section 404 of the Clean Water Act (CWA) regulates the discharge of dredged or fill material, which is defined as a pollutant, into waters of the United States by requiring potential dischargers to obtain a permit for such activities. The Section 404(b)(1) Guidelines provide the substantive environmental criteria by which all dredge and fill permit applications arc reviewed. The Guidelines consist of 4 basic steps: 1) evaluation of practicable alternatives; 2) evaluation of relation of discharge to other environmental standards; 3) assessment of significant degradation to waters of the U.S.; and 4) assessment of appropriate steps to minimize impacts. Wetland functional assessment is important in steps 1, 3, and 4. The use of wetland functional assessment techniques has typically been hindered by lack of time and resources, among other technical concerns, by the resource agencies implementing the Section 404 program. Functional assessment is critical to the Section 404 program since most decisions revolve around an assessment of wetland functions. The Hydrogeomorphic Classification for Wetlands (Brinson, 1993) and the developing functional assessment procedure shows potential for being rapid and inexpensive, scientifically-based and replicable. It is based upon functional indicators which can be recognized in the field and can form the basis for functional indices. The utility of the HGM procedure is illustrated using an example from West Kentucky.
William B. Ainslie

Forest Management and Wildlife in Forested Wetlands of the Southern Appalachians

The southern Appalachian region contains a variety of forested wetland types. Among the more prevalent types are riparian and bottomland hardwood forests. In this paper we discuss the temporal and spatial changes in wildlife diversity and abundance often associated with forest management practices within bottomland and riparian forests. Common silvicultural practices within the southern Appalachians are diameter-limit cutting, clearcutting, single-tree selection, and group selection. These practices alter forest composition, structure, and spatial hetereogeneity, thereby changing the composition, abundance, and diversity of wildlife communities. They also can impact special habitat features such as snags, den trees, and dead and down woody material. The value of wetland forests as habitat also is affected by characteristics of adjacent habitats. More research is needed to fully understand the impacts of forest management in wetlands of the southern Appalachians.
T. Bently Wigley, Thomas H. Roberts

Best Management Practices for Forested Wetlands in the Southern Appalachian Region

Forestry best management practices (BMPs) have been developed for all of the states included in the Southern Appalachian Region (Alabama, Georgia, Kentucky, North Carolina, South Carolina, Tennessee, Virginia, West Virginia). All of the state forestry BMPs were developed to reduce nonpoint source pollution from forestry operations. However, the states have developed BMPs that differ substantially with regard to methodology, particularly for forested wetlands. The state BMP guidelines vary in several major areas, including wetland types, BMP manual detail, streamside management zones, harvesting operations, site preparation operations, regeneration systems, road construction, and timber removal activities. An understanding of the similarities and differences between the state BMP guidelines will allow the forested wetland manager to comply with or improve upon existing forestry BMPs for wetlands.
W. Michael Aust

Reservoir Riparian Zone Characteristics in the Upper Tennessee River Valley

Impoundments in the upper Tennessee River Basin have inundated historic river riparian and mesic valley slope habitats. Fifteen major Tennessee Valley Authority (TVA) reservoirs, upstream of Chattanooga TN, have effected 50,000 ha of modern reservoir riparian zones on formerly mesic terrain. These zones were defined here as winter mudflats between winter pool shores and summer pool shores and summer riparian habitats with diminishing soil saturation from summer shores up to flood zone boundaries. Watts Bar (WB), the largest of these 15 projects in terms of area, was chosen for background and field analyses of the consequential reservoir riparian processes and expressions. WB, at the median age of areal TVA reservoirs, was closed in 1942. Transects were taken in the WB summer riparian forest after consideration of topoedaphics, species composition, and the level of contemporary disturbance. Regional bottomland forests were compared. Coefficients of species similarity showed 70% compositional similarity. The basal area (BA) density of WB summer riparian forests was not similar as was composition in regional bottomland stands. Four (of twelve) subjectively selected WB transect BA densities were compared nonparametrically and were the same (90% confidence) as other bottomland stands of like chronology. Overall however, WB stands averaged 19.6 m2/ha BA to 30.0 + for regional comparisons. Stocking was low, but measured litterfall was relatively high, resulting in similar biomass productivity corrected on a unit area basis. The winter mudflats showed expanding development of phenologically distinct herbaceous and graminoid communities under a five to six month drawdown exposure regime. Thermal modifications from the winter pool heat sink were determined to alter the mudflat microenvironment. A recent shortening of the drawdown period has interrupted the adapted life history strategy of the counter-seasonal plants, and seed maturity has been restricted. Erosion of the summer shore has been increasing the extent of the mudflats at the expense of the hydrologically influenced summer riparian habitat foreslope. The discernable trend of summer riparian stand succession over mesic expression will be limited by the height and hydric avoidance occasioned by an abrupt slope to mesic, unsaturated profile, conditions. Approximations of biomass production potential pre-and post impoundment have shown a 12:1 diminution from historic carbon detention, on a seasonal basis, within normal pool shore boundaries. Further approximations comparing the WB summer riparian forest carbon retention and detention to historic forest compartments highlighted the importance of a relatively copious, non-lignified, litterfall in the seasonally available carbon budget.
C. C. Amundsen

Wetland Restoration and Creation


Decision Sequence for Functional Wetlands Restoration

As wetland functions are being more clearly evaluated, demand is increasing for the ability to mitigate for specific wetland functions that have been degraded. When wetland restoration project goals specify functions, success of the project depends heavily on proper guidance for project siting, design, implementation, and monitoring. A decision sequence is presented for wetland restoration projects to help achieve functional replacement. This methodology incorporates site selection and design features for specified wetland functions into three phases of a project planning decision sequence. The first phase, site selection, situates a wetland where there is the potential to perform a function. Phases two and three, the incorporation of functional design features into design criteria and project plan development, focus on the optimization of the functional capacity of a site. An example is given of how a wetland restoration project planning team can consider enhancing vegetation diversity during the project plan development phase to achieve a goal of improved wildlife habitat.
M. M. Davis

Design and Implementation of Functional Wetland Mitigation: Case Studies in Ohio and South Carolina

Wetland development offers the opportunity to replace and enhance ecological functions lost through permitted wetland impacts. Components necessary for the restoration and creation of wetlands are presented and examples of wetland construction are described to illustrate the application of wetland design. Land contours, top soil, hydrology and vegetation were manipulated to develop wooded wetlands at sites in Ohio and South Carolina. In Ohio, approximately 30 ha of former crop land/sod farm were modified to bring water from the adjacent creek onto the site and hold it to saturate soils for wetland development. A 2.8 ha ponding area and channels were constructed, berms were built to slow the exit of stormwater runoff, and trees were planted in spring 1994. The mitigation site lies adjacent to a park and high school, thereby also providing community benefits and wetland education opportunities. In South Carolina, 9.5 ha of an abandoned soil borrow pit were converted into wooded wetlands, hydrologically connected to an adjacent swamp. Native plants were removed from the 4 ha of isolated wetlands to be impacted, and were augmented with nursery stock to create the mitigation wedand. Monitoring of vegetation, hydrology and wildlife usage of the constructed system continues to document wedand development and success.
Sue Ann McCuskey, Allen W. Conger, Hilburn O. Hillestad

EPW: A Procedure for the Functional Assessment of Planned Wetlands

The practice of compensating wetland losses through wetland construction, restoration, or enhancement has become more commonplace; however, an appropriate method for assessing replacement of wetland function has been lacking. The Evaluation for Planned Wetlands (EPW) was developed to meet this need. It is a rapid assessment procedure which documents and highlights differences between a wetland assessment area and planned wetland based on their capacity to provide six functions: shoreline bank erosion control, sediment stabilization, water quality, wildlife, fish (tidal, non-tidal stream/river, and non-tidal pond/lake), and uniqueness/heritage. The differences between wetlands are expressed in terms of individual elements, Functional Capacity Indices, and Functional Capacity Units. The results provide information on individual design elements and measures of functional capacity which are a necessity under current regulatory programs that require tangible goals and a method for calculating planned wetland size. EPW includes functional assessment models, a procedure for using these models during the planning/mitigation process, and guidelines for functional design.
C. C. Bartoldus


Additional information