Stream restoration practitioners generally include channel cross-sectional geometry, planform pattern, and profile in the development of a natural channel design. While there is considerable effort made in defining appropriate morphologic parameters via reference reach evaluation, regional relationships, and channel classification guidelines, we often fall short in terms of process-based thinking.

Bedload transport is a geomorphic process that is central to the development and maintenance of channel morphology. While practitioners of stream restoration acknowledge the importance of sediment transport, rarely is it fully integrated into natural channel design to establish proper channel stability.

The bed surface of Coastal Plain streams is dominated by mixed grain sizes, most of which are sand or finer (<2mm). As opposed to uniform sediments, the transport mechanics of these non-uniform mixtures are extremely complex. Furthermore, sediment supply to Coastal Plain streams is highly variable both spatially and temporally. These aspects present an additional layer of complexity in the natural channel design of Coastal Plain streams.

A poor estimate of the relationship between bedload transport with respect to sediment supply can reduce project success. If transport exceeds sediment supply, a restoration project may experience accelerated bed scour and channel degradation. If sediment supply exceeds transport, a design channel may unexpectedly aggrade and undergo bank erosion.

Despite a half century of intensive theoretical, empirical, and probabilistic approaches to the prediction of sediment transport, our ability to apply sediment transport models to these stream restoration problems is tenuous at best. Practitioners must continue to accept large uncertainty inherent to any sediment transport analysis. However, there are simple ways in which we can improve our thinking and reduce uncertainty in natural channel design.

Practitioners must understand the assumptions inherent in sediment transport modeling before selecting an appropriate model. There is no “magic” sediment transport model, but some approaches are more appropriate than others to the Coastal Plain setting.

There’s more to sediment transport than incipient motion. If sediment is mobilized, how do we know there is sufficient sediment supply to replace it? Evaluating the geomorphic setting can provide a meaningful framework for estimation of sediment supply. Relatively simple quantitative models can be used to predict any net adverse channel change for a given set of design conditions.

Large uncertainties with existing models can be reduced with some additional data collection. Even if found generally appropriate to mixed, sandy bed material in the Coastal Plain, a sediment transport model will provide little guidance in the absence of any field data. However, by fitting a transport model to some field data, transport rates can be extrapolated to a broader range of events.

About the speaker:

Ellen McClure is a geomorphologist at Biohabitats, Inc. in Timonium, MD. Her responsibilities include watershed and stream channel assessment, hydrologic and hydraulic modeling, and preparation of stream restoration designs.

Ms. McClure received a B.S. in Geological Sciences from the University of Washington and a M.S. in Geology and Civil Engineering at Oregon State University. Before joining Biohabitats in 2000, Ms. McClure worked as a hydrology and geomorphology consultant at PWA, Inc. in San Francisco.

Ellen McClure

Biohabitats, Inc.

15 West Aylesbury Road

Timonium, MD 21093

emcclure@biohabitats.com

http://www.biohabitats.com/

A Comparison of Soil Properties and Processes in Natural and Mitigation Wetlands of the Southeastern Coastal Plain

Greg Bruland, Duke University Wetland Center, Durham, NC

Mitigation involves the creation or restoration of wetland structure and function that were lost during development. As mandated by Section 404 of the CWA, the Army Corps of Engineers (ACoE) requires that the hydrology and vegetation of mitigation wetlands meet hydrologic and vegetative success criteria during a 5 year monitoring period following creation or restoration. However, the ACoE monitoring process does not require any monitoring of soil properties or processes. This is a cause for concern for various reasons because: (1) soil forms the foundation of these developing ecosystems, (2) soil properties can be limiting to vegetative growth and survival due to lack of nutrients and compaction, and (3) soil is the medium for biogeochemical processes that transform and retain nutrients. Furthermore, very little research has been attempted to examine how differences in soil properties leads to differences in critical wetland soil processes such as phosphorus (P) sorption, and denitrification. Thus, the objectives of this study are to: (1) quantify differences in soil properties (bulk density, texture, moisture, organic matter, pH, and microbial biomass) of mitigation and natural wetlands, (2) examine how differences in soil properties lead to differences in soil process (P sorption, denitrification). Results to date indicate that the soils of mitigation wetlands generally have higher bulk density and sand content, and lower moisture, organic matter, and microbial biomass than their natural counterparts. This is turn can lead to lower P sorption capacity and denitrification rates in mitigation wetlands. Thus, while mitigation wetlands may meet the ACoE’s hydrologic and vegetative success criteria in the early years of development, soil properties and processes in certain types of mitigation sites may not functionally replace those of the natural wetlands that were lost due to development.

About the speaker:

Greg Bruland is a Ph.D. candidate with the Duke University Wetland Center in Durham, NC. His current research involves the comparison of soil properties and processes of natural and mitigation wetlands in the southeastern coastal plain. His first publication is currently in press with the journal Wetlands Ecology and Management. This paper describes some of his initial graduate research investigating the effects of restoration on the hydrology, soils and water quality of a Carolina Bay complex in Cumberland Co., NC.

Greg Bruland

Duke University, Box 90328

Durham, NC 27708-0328

glb5@duke.edu

http://www.env.duke.edu/wetland/students.htm

Reference Reach and Gage Survey Data Analyses for Coastal North Carolina

Barbara A. Doll, PE and Angela D. Moreland

Restoration and stabilization of degraded streams is a priority focus for many federal, state and local government agencies and nonprofit groups. Many restoration practitioners strive to restore stability to disturbed streams by using a natural channel design approach. This approach transitions degraded channels to more stable forms by restoring and/or adjusting natural stream characteristics, including a properly sized bankfull channel, adequate floodplain width, meanders, riffles, and pools. Stability is achieved when the stream has developed a stable dimension, pattern, and profile such that, over time, channel features are maintained and the stream system neither aggrades nor degrades (Rosgen, 1996). Successful stream restoration requires an understanding of the causes of degradation; specific knowledge of the stream’s present state; and understanding of the stream's most stable dimension, pattern and profile based on its present valley type and flow regime. In addition, quantitative knowledge of stable streams is necessary to determine the stable dimension, pattern and profile that can be applied in a restoration design.

A reference reach is a stable river segment that represents a stable channel within a particular valley morphology (Rosgen, 1998). Reference reaches provide the numerical template that can be applied to unstable reaches. Reference stream-channel morphology relationships are valuable tools for stream-restoration professionals. Designers and reviewers should use references reaches to determine appropriate stream-channel dimension, pattern and profile for various stream types and watershed conditions. The reference stream is not necessarily pristine (completely unimpaired). It instead is a reach that characterizes a stable morphology within its setting.

Channel-morphology relationships on reference streams are valuable tools for engineers, hydrologists and biologists involved in stream restoration and protection. Dimensionless ratios are useful tools for comparing the data from multiple reference streams, which have a different bankfull dimensions and discharges. Dimensionless ratios are also essential design tools for scaling the reference reach dimension, pattern and profile data to the design stream, which likely has a different bankfull dimension and discharge. In addition, channel morphology relationships can be used to evaluate the relative stability of a stream channel.

The natural channel design approach also relies on the accurate identification of the bankfull channel dimension and discharge. Hydraulic geometry relationships that relate bankfull stream channel dimensions and discharge to watershed drainage area are therefore useful tools for stream restoration design. Dunne and Leopold (1978) first developed hydraulic geometry relationships for the bankfull stage, also called regional curves.

This presentation will include preliminary regional curve and morphological reference reach relationships for 7 reference reach and 7 USGS gaged streams in the Coastal Plain. Reference and gaged streams included in the presentation represent the major physiographic regions within the Coastal Plain: Upper, Middle, Lower and Sandhills regions.

Literature Cited:

Dunne, T. and L.B. Leopold, 1978. Water in Environmental Planning. W.H. Freeman Co. San Francisco, CA. 818 pp.

Rosgen, D.L., 1998. The reference reach - a blueprint for natural channel design. Draft Presented at ASCE Conference on River Restoration in Denver Colorado - March, 1998. ASCE. Reston, VA.

Rosgen, D.L., 1996. Applied River Morphology. Printed Media Companies, Minneapolis, Minnesota. 350 pp.

About the speaker:

Barbara Doll is water quality specialist for N.C. Sea Grant, which is a federal/state program that promotes the wise use of coastal resources. Based at NC State University, Barbara provides information to the public and local governments about water quality status, research and regulations. Much of Barbara’s current work is focused on repairing degraded stream systems and reducing the impacts of stormwater runoff and nonpoint source pollution. With grant funding from both state and federal agencies, she is currently working on several restoration projects. Projects include repair of a highly degraded urban stream located on the NC State University campus; restoration of a small tributary of Hewlett’s Creek on Pine Valley Golf Course in Wilmington; and restoration of a tributary of Yates Mill Pond in Raleigh.

Ms. Doll has bachelors and master's degrees in civil engineering from N.C. State University. Before joining Sea Grant in 1992, she specialized in water resources and surface water quality in consulting work and graduate school.

Barbara A. Doll

North Carolina Sea Grant

101 F 1911 Building, Box 8605

NC State University

Raleigh NC 27695-8605

919/515-5287

919/515-7095 fax

barbara_doll@ncsu.edu

The Emergency Watershed Protection Program and Its Implementation Following Hurricane Floyd

Michael J. Hinton, USDA Natural Resources Conservation Service, Raleigh, NC

The Emergency Watershed Protection (EWP) Program is administered by the USDA Natural Resources Conservation Service (NRCS) to assist local sponsors address hazards to life and property created by natural disasters that cause a sudden impairment of watershed functions. Hurricane Floyd brought unprecedented rainfall to most of North Carolina’s coastal plain region resulting in record flooding. All of the major river basins east of Raleigh experienced flows in excess of the 500-year event. Fifty-two lives were lost and damages exceeded $6.0 billion. Flooding killed over 3 million turkeys and chickens, and 40,000 swine. Wind and flood flows resulted in the placement of a large numbers of trees and other debris into stream and river channels. High flows also contributed to significant streambank erosion in many locations.

The EWP Program was used to provide technical and financial assistance for the disposal of over 2 million dead animals. Disposal methods included burial, composting and incineration.

Debris removal from streams and rivers was completed in 24 eastern North Carolina counties. Debris was removed from channels where it created an increased threat to life and property due to a greater risk of flooding. The EWP program was not used to address pre-existing problems such as poor drainage or beaver damage. Debris was removed from over 1,800 miles of streams and rivers using EWP Program technical and financial assistance.

Because of the potential adverse impacts associated with debris removal, NRCS worked closely with federal and state resource management agencies, sponsors, and contractors to ensure that work was completed without significant adverse impacts to water quality, aquatic habitat, or riparian areas. Guidelines for debris removal were developed in cooperation with state and federal agencies following Hurricane Fran (1996) and were used in Floyd debris removal projects. The guidelines were incorporated into NRCS contract documents. In most cases, section 404/401 permits were not required. Navigable waters were subject to Section 10 regulations, and permits were acquired prior to any work.

Additionally, NRCS provided state and federal review agencies a copy of quad maps showing the location of all proposed work. When there were potential impacts to endangered species, water quality, cultural resources, aquatic habitat, or other environmental concerns, NRCS worked with the appropriate resource agencies to modify the proposed work to avoid impacts. NRCS and Soil and Water Conservation District inspectors monitored the debris removal contracts to ensure that contract specifications were followed and that adverse impacts were avoided.

As a result of the cooperation of state and federal agencies, contract provisions, and inspection, debris removal contracts were completed in a manner that met program objectives regarding the protection of life and property without adverse impacts to the environment. Debris removal was limited to that which posed a threat to life and property. Significant woody debris was left in the streams and rivers when it was sufficiently anchored and positioned where it posed no threat. Inspection of completed work revealed a good distribution of both large and small woody debris.

While most of the EWP effort focused on debris removal, streambank stabilization and stream restoration was completed as well. Record storm flows combined with high velocities caused significant bank erosion in a number of locations. NRCS completed 9,800 feet of streambank stabilization and stream restoration. Principles of natural channel design were used to evaluate stream conditions and to determine the type of restoration appropriate for the site. Priority 1 or 2 restoration was implemented where possible. Priority 4 restoration (stabilization in place) was implemented where roads, utilities, or buildings limited access to the floodplain.

About the speaker:

Mike Hinton is the EWP Program Manager for the Natural Resources Conservation Service in North Carolina. He has been with NRCS for 22 years and has worked in South Carolina, Mississippi, and North Carolina.

Mr. Hinton received a B.S. in Zoology and a M.S. in Wildlife Biology from Clemson University.

Mike Hinton

USDA – NRCS

4405 Bland Road, Suite 205

Raleigh, NC 27613

mike.hinton@nc.usda.gov

Bankfull Regional Curves for the Coastal Plain Physiographic Province of North Carolina

William V. Sweet and Jens W. Geratz, EcoScience Corporation, Raleigh, NC

Bankfull regional curves relate stream-channel geometrics to watershed size for specific physiographic regions. This paper presents bankfull-curve information and bankfull recurrence intervals for North Carolina’s Coastal Plain physiographic province. Cross-sectional and longitudinal survey data from stream reaches with gage stations and un-gaged, stable reference reaches were used to compute bankfull-channel dimension and profile information. Power-function regression analysis generated watershed size-dependent relationships for bankfull discharge, cross-sectional area, width and mean depth. Recurrence intervals of bankfull events were estimated by Log-Pearson Type III distribution of peak-annual data to average 0.61 years, ranging from 0.21 to 1.09 years. Partial-duration series methods, which utilize average daily discharge values at gage sites, determined that recurrence intervals for bankfull events ranged from 0.11 to 0.31 year, with an average 0.18-year period. In any case, certain bottomland regions of the Coastal Plain province appear to have unique bankfull-hydraulic geometrics.

About the speaker:

Jens Geratz is a restoration ecologist with EcoScience Corporation located in Raleigh, N.C. His responsibilities include staff management, project oversight and review, and development of technical studies. Mr. Geratz’ specialties includes stream and wetland mitigation planning, geomorphological stream surveys, and plant ecology.

Mr. Geratz received a B.S. degree in Horticultural Science and a M.S. degree in Forestry (Ecological Restoration Program) from North Carolina State University. Since joining EcoScience in 1998, Mr. Geratz has designed and implemented multiple stream and wetland restoration projects located throughout the Piedmont and Coastal Plain of North Carolina.

Jens Geratz

EcoScience Corporation

1101 Haynes Street

Suite 101

Raleigh, NC 27604

geratz@ecosciencenc.com

The Development of Bankfull Hydraulic Geometry Relationships for Streams of the Georgia Coastal Plain

Steve Bevington, William A. Harman, John Hutton

Bankfull hydraulic geometry relationships, also known as regional curves, relate bankfull stream channel dimensions to watershed drainage area. Established regional curves are important to channel assessment and stream restoration efforts as they can confirm identification of bankfull stage and channel dimension in un-gaged watersheds and help estimate the appropriate bankfull dimension and discharge for natural channel designs. This paper describes results of bankfull hydraulic geometry relationships developed for streams of Georgia’s Coastal Plain. Ten USGS gage stations were identified that had a minimum of 10 years of continuous or peak discharge measurements, no major impoundments, no significant change in land use over the past 10 years, and less than 10% impervious cover over the watershed area. To supplement data collected in these gaged watersheds, eleven stable reference reaches in un-gaged watersheds meeting the same criteria were also included in the study for a total of 20 sites. Drainage areas of the selected sites ranged from 0.32 to 93.4 square miles. Sites from both the Upper and Lower Coastal Plain of Georgia were included. Cross-sectional and longitudinal surveys were conducted at each study reach to determine channel dimension, pattern, and profile information. Sediment samples were also collected to assess bed material. Log-Pearson Type III distributions were used to analyze annual peak discharge data for USGS gage station sites. Estimated return intervals for bankfull discharge at the selected sites ranged from 1.0 to 1.3 years. Power function relationships were developed using regression analyses for bankfull discharge, channel cross-sectional area, mean depth, and width as functions of watershed drainage area. Contrary to pre-study expectations, no significant differences were observed between regional curves estimated for the Upper and Lower Coastal Plain hydro-physiographic regions. These relationships based on Georgia streams will be compared to relations from other Southeastern State coastal plains, including North Carolina, in an effort to compliment and extend regional relationships. Results of this study will be discussed with particular attention given to issues relevant to coastal stream processes including multi-thread channels, non-fluvial channel formation in wetlands and the stability of sand bed streams.

About the speaker:

Mr. Bevington has 17 years experience in water quality and natural resource science. He has provided technical assistance for basinwide water quality planning efforts and the development of watershed management strategies. His background includes experience and formal training in stream and habitat restoration, riparian and wetland ecology and hydrology. Mr. Bevington has extensive experience with restoration project evaluation and selection, and management of GIS implementation. Mr. Bevington holds a Masters in Environmental Management from Duke University and a BS in Zoology from the University of Wisconsin, Madison.

Buck Engineering

8000 Regency Parkway

Suite 200

Cary, NC 27511

(919) 463-5488

An Assessment of the Effectiveness of Cross-Vane Structures Used on Shawneehaw Creek and Clark Creek in North Carolina

Amanda J. Todd, Stantec Consulting

The primary purpose of this research was to monitor and assess the effectiveness of cross-vane structures used at Shawneehaw Creek in Avery County, North Carolina and on Clark Creek in Watauga County, North Carolina. This thesis was designed to monitor these projects for six months after construction, to establish baseline data for future research on the two sites, and to provide a foundation for a monitoring protocol that could be used for other projects on cross-vane stability in the region. One important gap in the knowledge base about stream restoration structures this study addressed is the lack of published data of the success or failures of cross-vane structures used with Natural Channel Design.

The six cross-vanes at Shawneehaw Creek and four cross-vanes at Clark Creek were monitored for a six month period beginning June 2001. Data were collected on the stream pattern, profile, and dimension before construction in May and four times after construction at both sites. Two cross sections were established at each cross-vane immediately after construction. One cross-section for each cross-vane was established over the invert of the structure and one cross-section was established over the location of the scour hole immediately after construction. Longitudinal Surveys, Cross-Sectional Surveys, Cross-Vane Measurements, Pebble Counts, and Visual Assessments were completed at each site on multiple occasions. These data allowed for precise documentation of the short-term changes in stream channel conditions and provided valuable insights into why cross-vane structures might fail in these and similar streams in the region.

Four out of the ten Cross-Vane structures failed to meet the objectives of protecting the stream banks and streambed within the first six months. The primary reasons for the failures are: 1) the cross-vane angles were not designed according to the design specifications, 2) the cross-vane slopes were too steep or too flat, and 3) the type of streambed material. The study concludes by suggesting there is a need for continued efforts by scientists to study and refine the structures and techniques used for stream restoration within different geographic settings. While this thesis has provided a foundation for a monitoring protocol of cross-vane structures used in the Appalachian region, the protocol needs to be expanded and refined for long-term monitoring in this region and other geographic settings.

About the speaker:

Amanda Todd is an Environmental Scientist with Stantec Consulting in Raleigh, North Carolina. Her responsibilities include: writing mitigation and feasibility reports, surveying existing and reference reach stream sites, and construction oversight.

Ms. Todd holds a B.S. degree in Natural Resource Management from North Carolina State University. She worked for the NCSU Water Quality Group while she was an undergraduate student and continued to work for them while in graduate school. Ms. Todd joined Stantec Consulting in 2002 after completing her Master’s in Geography from Appalachian State University.

Amanda J. Todd

801 Jones Franklin Road, Suite 300

Raleigh, NC 27606

919-851-6866

atodd@stantec.com

www.stantec.com

A Comparison of Natural and Design Plunge Pool Morphology in Urban Stream Systems

C.J. Estes, RLA, Estes Design Services, Charlotte, NC

C.J. Allan, Dept. of Geography and Earth Sciences, UNC Charlotte, Charlotte, NC

In 1997 The City of Charlotte began investigating the implications of its current maintenance practices for natural channels at road culvert crossings. The investigations were initiated after it became apparent that certain implications from these practices could result in extreme instability of the receiving natural channels with the possibility of reinitiating a cycle of instability in an otherwise stable built out watershed.

Naturally formed plunge pools are a common morphologic feature in many urban stream systems where the transition between pipe and natural stream systems occur. Initially road culvert crossings will result in scour at natural channel transition points. In streams that have not been modified for a period of time and that have adapted to the urban watershed display geomorphic characteristics of stability. It is in these streams where plunge pools serve as significant stream energy dissipaters, increasing flow resistance and enhancing stream channel stability. Such features may also provide habitat diversity and serve as refugia for stream biota during low flow periods.

We present the morphologic characteristics of naturally formed plunge pools associated with culvert outlets in the metropolitan Charlotte area. Plunge pool dimensions surveyed include maximum depth, length and width, longitudinal and side slopes as well as bed material. Culvert outlet dimensions and hydraulic characteristics of the scouring jet for each study site are also reported. These data are compared to plunge pool dimensions predicted for both free fall and submerged culvert hydraulic conditions as determined from laboratory flume studies. Comparisons between collected field data and the laboratory produced methodologies suggest sharp contrast between individual design methodologies themselves and apparent inadequacies of common design standards.

The implementation costs for constructed plunge pools are compared to those for armored riprap aprons that are traditionally employed at culvert outlets.

The end result of this research is recommended design standards to achieve designed natural plunge pools.

About the speaker:

Christopher J. Estes is president of Estes Design Inc. an environmental design and consulting company that specializes in stream restoration services. These services include stream assessment, classification, design, construction administration, monitoring and wetlands assessment / design.

Mr. Estes received a B.A. in Landscape Architecture from the School of Environmental Design at the University of Georgia in 1988. Before starting Estes Design Inc. Mr. Estes worked for the City of Charlotte Engineering Department for eleven years. Mr. Estes has initiated and managed the Charlotte’s stream bioengineering program for 8 years with over 60 stream projects and 15,000 feet of urban stream stabilized using bioengineering techniques. During this time Mr. Estes has also been a designated City resource for stream and wetlands restoration design as well as permitting, training and research. Mr. Estes initiated and managed the City of Charlotte’s four collaborative natural channel research projects with UNCC.

C.J. Estes, RLA

Estes Design Inc., P.O. Box 79133 Charlotte, NC, 28271

mailto:Chris@EstesDesign.com

C.J. Allan

Dept. of Geography and Earth Sciences, UNC Charlotte, Charlotte, NC, 28223, cjallan@uncc.edu

Use of Rock for Natural Stream Restoration in Coastal Plain Settings

Vince Sortman, Biohabitats. Inc.

Natural stream restoration design utilizes principles of fluvial geomorphology to obtain channel cross section, profile, and plan-form dimensions that will allow the restored channel to function in a state of dynamic equilibrium – that is, the channel neither aggrades nor degrades and maintains its plan, profile, and section. Even in a state of dynamic equilibrium, a newly graded channel needs stabilization (preferably in the form of woody vegetation) to hinder bank erosion. In urban settings, where utilities or private property need to be protected from channel adjustment, stabilization may need to be in the form of native rock.

Stream channels in coastal plain regions are usually flowing in sandy substrate with no naturally occurring rock outcrops. The lack of naturally occurring rock presents a dilemma for stream restoration, especially in urban areas. Should rock be used to stabilize outside meander bends, step/pools, or grade control structures? These are typical uses for rock in type B and C channels in piedmont and mountain regions. But should rock be used in the same scenarios in the coastal plain? If the goal of the project is to restore a natural channel, and no rock is found in the degraded channel or in the reference reach, then it would make sense not to use rock in the restoration. But if the channel and its floodplain have been altered and affected by development and urbanization, is there anything wrong with using rock to create a natural-looking, stable channel.

A number of stream restoration projects have been chosen to demonstrate the use of rock for stream restoration in the coastal plain. All of the projects are on urban streams that have been altered and/or degraded by an urban hydrology. Some of these projects have been very successful in creating natural, stable channels. Others have been only partially successful.

About the speaker:

Mr. Sortman is a fluvial geomorphologist with Biohabitats, Inc. in Timonium, Maryland. He received his Bachelor of Science degree in Geological Sciences from the Pennsylvania State University and his Master of Science degree in Geology from the Colorado State University. At CSU he studied fluvial geomorphology under Dr. Stanley Schumm. At Biohabitats, Mr. Sortman is the lead stream restoration specialist, responsible for the design and construction supervision of all stream restoration projects. He has designed dozens of stream restorations throughout the eastern United States based on fluvial geomorphic principles and natural channel processes. He has also taught fluvial geomorphic principles and channel restoration techniques at numerous seminars throughout the country.

Incremental Tree Ring Growth as a Tool to Evaluate the Influence of Regulated River Flow on a Floodplain Swamp

Joe Berg, Biohabitats, Inc.

A detailed assessment of the effect of river regulation on bottomland forest resources in the Oconee River was undertaken to address permit requirements for the relicensing of a dam associated with an existing hydroelectric facility. The project area is in central Georgia and extends from the city of Milledgeville 60 river miles downstream to the town of Dublin. The floodplain near Milledgeville is relatively narrow and largely in agricultural cover. However, once the river traverses the fall zone and enters the Coastal Plain province, the floodplain dramatically widens, with widths of up to 6-miles, and an average width of 2 ½ miles. Tree growth ring data from large specimen trees representative of the species inhabiting wetter portions of the floodplain were collected using increment coring techniques (Fritts 1969, Phipps 1985). These data were evaluated for evidence of any relationship with patterns of river discharge and the onset of river regulation. While a number of species were evaluated, most data was collected for water tupelo (Nyssa aquatica) and laurel oak (Quercus laurifolia). The results of the tree ring study indicated that there was no statistically measurable reduction in tree growth between the 40-yr period prior to the construction and operation of the dam and the 40 year period of time following dam operation. Similarly, tree ring width data did not evidence a reduction in growth of water tupelo or laurel oak from the pre- to post-dam period, and although correlations with river discharge for wet and dry periods were significant, the correlation coefficients never explained a large proportion of the observed variability in ring width.

Conclusions

The results of these studies indicate that even though high frequency inundation events have decreased, and areas of the floodplain subject to frequent inundation have decreased, no adverse effects are evident or are predicted to result to the BLH wetland resource. One reason may relate to the relatively long duration of flooding present in the study area. The floodwater enters the floodplain more quickly than it exits, so that even when the river is above bankfull for hours to days, the floodplain may be inundated for days to weeks and sloughs and other depressions in the floodplain may be ponded for months. As a result, the effect of river regulation on duration of floodplain inundation is not expected to be important as long as the floodplain is inundated by the less frequent but larger annual flood events. In addition, many recognize the robust nature of the BLH forest community. Natural variations in precipitation, levee breeches, exceptionally wet or dry periods, etc. are commonplace in these systems, so the species present typically are able to tolerate a broad range of hydrologic regimes, as long as less robust species are periodically excluded by events beyond their range of tolerance. This floodplain remains one of the better examples of the typical BLH swamp in the southeast.

About the speaker:

Joe Berg is an ecosystems ecologist with Biohabitats, a consulting firm specializing in restoration of natural resources.

Mr. Berg has a M.S. in Marine, Estuarine and Environmental Sciences from the University of Maryland, and has been working in the resource assessment and restoration field for the past 20 years.

Joe Berg

Biohabitats, Inc.

15 West Aylesbury Road

Timonium, MD 21093

joe@biohabitat.com

http://www.biohabitats.com/

Stream Bank Revegetation: Options for the Coastal Plain

Ellen Colodney, Coastal Plain Conservation Nursery, Edenton, NC

Revegetation of disturbed stream banks is an integral part of stream restoration. Stream bank vegetation can greatly improve aquatic, terrestrial, and aerial wildlife habitat, absorb excess nutrients, soften the blows of heavy rainfall, provide aesthetic pleasure to us humans, and keep all that dirt we move from washing away.