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  • Introduction & Project Cooperators

    *Please note* this project has been completed and we are currently working to update this web page.

    In 2001, the New Jersey Legislature directed the Pinelands Commission to prepare an assessment of the key hydrologic and ecological information needed to determine how the current and future water-supply needs within the Pinelands area may be met while protecting the Kirkwood-Cohansey aquifer system and avoiding any adverse ecological impact on the Pinelands area. The enabling legislation, which appropriated $5,500,000 from the Water Supply Fund for the preparation of the assessment, also required that the assessment be implemented in cooperation with the New Jersey Department of Environmental Protection, Rutgers University, the United States Fish and Wildlife Service, and the United States Geological Survey.

    Scientists from the cooperating agencies and institutions prepared a work plan for the Kirkwood Cohansey Project  which was approved by the Pinelands Commission in October 2003. The work plan consists of several components that are to be completed by project cooperators. The anticipated completion date for the Kirkwood-Cohansey Project is June 2009. 

    The Kirkwood-Cohansey Project Cooperators

    Pinelands Commission
    Robert A. Zampella, Ph.D.
    John F. Bunnell
    Kim J. Laidig
    Nicholas A. Procopio, Ph.D.
    Allison M. Brown, Ph.D.
    Larry L. Liggett
    Russell Davis

    U. S. Geological Survey
    Robert Nicholson
    Anthony Navoy, Ph.D.
    Jonathan G. Kennen, Ph.D.
    Richard Walker

    U.S. Fish and Wildlife Service
    Carlo Popolizio
    Lisa Arroyo

    Rutgers University
    Joan G. Ehrenfeld, Ph.D.
    Richard G. Lathrop, Ph.D.
    Ming Xu, Ph.D.
    Eric Hamerlynk, Ph.D. 

    N. J. Department of Environmental Protection
    Kathleen Strakosch Walz
    Laura Nicholson

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  • Primary Research Questions

    The work plan addresses two major research questions:

    First, what are the probable hydrologic effects of groundwater diversions from the Kirkwood-Cohansey aquifer on stream flows and wetland water levels?

    Second, what are the probable ecological effects of induced stream-flow and groundwater-level changes on aquatic and wetland communities?

    The approach used to answer these two related research questions includes several coordinated steps. First, study areas were selected. A detailed study of these representative areas will provide the information needed to develop and implement groundwater-flow models that can be used to predict the probable hydrologic changes resulting from groundwater diversions. Next, ecological models that relate the distribution of biological communities and individual species to stream flow or the depth, duration, and frequency of saturation and flooding will be developed. Finally, the ecological models will be linked to the hydrologic models to evaluate the possible landscape-level ecological effects of different water-diversion scenarios.

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  • Study Areas

    The setting for the Kirkwood-Cohansey Project includes several Pinelands watersheds that represent a range of hydrologic, geological, land-cover, and ecological conditions. The McDonalds Branch, Pump Branch/Albertson Brook, and Morses Mill Stream basins are the sites for coordinated studies of hydrology and wetland ecology. Additional wetland studies are being conducted in the Skit Branch and East Branch Bass River drainage basins. The Batsto River system is the primary study area for stream-community investigations. This drainage includes a range of stream orders, water-quality conditions, and land-use characteristics. Intermittent-pond and anuran studies are being conducted within the proposed study areas and elsewhere.

    K-C study areas

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  • Hydrology

    The U. S. Geological Survey (USGS) is examining the hydrologic system that supports Pinelands aquatic and wetland communities. The investigations focus on aspects of the hydrologic system that control groundwater and surface-water flow, depth to water in wetlands, and interactions between groundwater, wetlands, and surface waters. A particular emphasis of this part of the project is the development of models to quantitatively evaluate the response of the aquifer system in the study areas to hydrologic stresses, including seasonal changes in recharge, drought, climatic change, and groundwater withdrawals. The goal is to develop hydrologic models that can be applied throughout the Pinelands area to determine how the Kirkwood-Cohansey aquifer system interacts with wetlands and aquatic systems and how these interactions are affected by water withdrawals. This goal will be achieved by completing several coordinated tasks.

    Cross section of Coastal Plain

    The USGS is constructing a hydrogeologic framework of the study areas that describes the major properties of the Kirkwood-Cohansey aquifer that influence ecologically important hydrologic regimes. The USGS completed bore-hole geophysical logs to define sediment composition and hydraulic properties and has used ground penetrating radar (GPR) to map subsurface geologic conditions. Slug tests were also performed to evaluate the permeability of the sediments. During a slug test the water level in a small diameter well is quickly raised or lowered. The rate at which the water level falls or rises is related to the sediment permeability.

    Sediment boring

    Ground-penetrating radar (GPR)

    To characterize groundwater levels in the study areas, the USGS has installed a network of monitoring wells ranging in depth from 5 ft to about 250 ft. Water levels are being recorded continuously at 25 of the 140 wells. The USGS is also monitoring stream flows in the study areas by operating seven continuous stream gages with satellite telemetry. Real-time stream data are available on-line at

    Well drilling

    Stream gage with satellite telemetry

    The USGS has also installed new staff gages throughout the study areas, including the Batsto River where fish and macroinvertebrate studies are being conducted. The staff gages are being used to estimate stream discharge and complete seepage runs. During a seepage run, staff gages positioned at upstream and downstream locations are measured and the difference between the two measurements is used to determine the volume of groundwater discharging to the stream reach between the two gages.

    Staff gage

    Evapotranspiration (ET) is a major component of the hydrologic budget. Using cutting-edge technology, the USGS is monitoring evapotranspiration in the field to develop a method for determining ET at the watershed scale. A 24-m instrumented tower is currently situated in the McDonalds Branch study basin where it is collecting meteorological data above the forest canopy.  Instrumentation on the tower is recording several variables, including vertical wind speed and vapor density, which are being used to estimate ET.

    USGS ET Tower

    The USGS will use the hydrogeologic information and appropriate mathematical models to evaluate the effect of water withdrawals on water-level and stream-flow regimes. The results of hydrologic modeling will be integrated with models used to evaluate the ecological response to changes in hydrologic regimes.

    Hydroecological model

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  • Species and Community Indicators

    Species and community level studies are focused on wetland and aquatic communities and associated species, emphasizing indicators that have been studied previously and that can be used to develop region-wide Pinelands ecosystem models. Thesee indicators include wetland-forest communities and individual indicator species that comprise these communities, swamp pink (Helonias bullata ), intermittent-pond vegetation, frogs found in intermittent ponds, and stream fish and macroinvertebrate communities. Ecological processes such as nitrogen cycling, photosynthesis, and evapotranspiration are also addressed.

    Wetland-forest Communities

    Hydrologic regime is the major factor underlying the upland-to-wetland vegetation gradients that characterize the Pinelands region.  The central question that will be addressed as part of this project component is how wetland-forest plant species and plant communities respond to changes in hydrology.  Pinelands Commission scientists are conducting field studies that relate the distribution of individual indicator species and forest types to variations in water level, soil moisture, texture and organic-matter content, and disturbance, among other factors.  Commission scientists established 201 study plots, representing nine different wetland forest community types, and instrumented each plot with a water-level observation well. The results of these studies will be used to develop models for predicting possible shifts in species distributions and community composition that may result from simulated changes in water-table levels.

    Sampling wetland vegetation 

    Swamp Pink (Helonias bullata)

    Swamp pink (Helonias bullata) is a federally listed endangered wetland plant whose limited geographic distribution currently extends from New Jersey to Virginia.  Swamp pink is generally associated with water-saturated muck soils of hardwood swamps and Atlantic white cedar swamps. 

    The U.S. Fish and Wildlife Service and the Pinelands Commission are conducting field studies of populations in the Cedar Creek and North Branch Rancocas Creek watersheds to describe the distribution and abundance of swamp pink plants along hydrologic gradients and determine what hydrologic regimes are associated with swamp pink colonies.  Each site has been equipped with several staff gages and wells.  These results will be used to develop regression models describing potential changes in swamp pink distribution in response to simulated changes in hydrologic regime.

    (Helonias bullata ) flower

    Intermittent-pond Vegetation

    Intermittent ponds that support open-water, emergent-herb, and shrub communities are found throughout the Pinelands.  Many support plant species that are rare in New Jersey.  Annual and seasonal variations in water depth control the distribution of plant species and vegetation zones found in intermittent ponds.  Pinelands Commission and NJ Department of Environmental Protection scientists are studying plant zonation, water-level patterns, and water-quality, among other factors, at fifteen ponds to address questions similar to those dealing with wetland-forest communities.  As with the other ecological studies, regression models will also be developed to simulate potential changes in pond vegetation associated with altered hydrology. 

    Burnt Pond

    Sampling pond vegetation

    Anuran-larval Development

    Intermittent ponds are important breeding habitat for many native Pinelands frog and toad species, including Pine Barrens treefrogs, northern spring peepers, and southern leopard frogs.  The successful recruitment of these species depends on the maintenance of adequate water levels for larval development.  Altered hydrology may have a more pronounced effect on late-breeding species such as the Pine Barrens treefrog because their transformation from larvae to adults occurs closer to the period when ponds usually dry. The central question to be addressed by the anuran research conducted by Pinelands Commission scientists is how larval development is related to intermittent-pond hydrology. 

    Pine Barrens treefrog tadpole with legs

    Pine Barrens treefrog metamorph

    Pine Barrens treefrog adult male.

    Stream Fish and Macroinvertebrates

    Fourteen native-fish species may be found in Pinelands streams, and several nonnative species are associated with waters characterized by elevated pH.  Although native fishes are adapted to the shallow and slow moving waters that typify the Pinelands, the conditions associated with small headwater streams may limit the distribution of some species and influence species richness.  Lower species richness in headwater streams may be related to the intermittent nature of these habitats or to low dissolved oxygen concentrations associated with low flows.


    Aquatic macroinvertebrates are a dominant component of the diet of most native Pinelands fish species.  Current, substrate, and oxygen are among the most important factors influencing the distribution and abundance of stream macroinvertebrates. These three factors are interrelated, with current partly determining both sediment type and dissolved oxygen levels.

    Sorting aquatic insects

    USGS ecologists, assisted by Pinelands Commission researchers, are conducting stream studies to address two related questions.  First, how do stream fish and macroinvertebrate assemblages respond to variations in streamflow regimes?  Second, how do site-specific habitat variables, such as temperature, dissolved oxygen, bank cover, stream vegetation, sediments, and channel morphology, interact with stream-discharge to affect fish and macroinvertebrate composition? The results of the field studies will be used to develop appropriate models relating community and species gradients to natural and induced changes in the streamflow regimes.


    Water-quality sampling

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  • Ecological-process Indicators


    Variations in nitrogen content and dynamics in forest soils are frequently associated with soil moisture. A laboratory and field study, conducted by Rutgers University scientists, will assess whether unsaturated conditions associated with lowered water-table levels promote increased nitrogen mineralization and nitrification in dry pine-lowland, wet pine-lowland, and cedar swamps soils, resulting in pulses of mineral nitrogen to wetland systems.

    Soil sampling 

    Physiological Indicators

    In plants, stress due to marginal-growth conditions associated with altered hydrologic regimes may be reflected by physiological responses long before death or obvious growth reductions become apparent. Because many of the indicator-plant species to be studied are woody shrubs, their response to alterations in water regime may be slow. It can be expected that wetland-adapted plants will experience drought stress if subjected to hydrologic conditions that are optimal for upland plants. Moreover, differences in tolerance to both dry soils and wet soils may eventually drive changes in community composition. Physiological measurements can serve as an indicator of the stresses that may eventually lead to changes in community composition.

    Transpiration and photosynthesis are two physiological processes that may be affected by water availability. In this study, the balance between the ability of the plant to take up water and the evaporative demand on water at the leaf surface will be measured. When evaporative demand is greater than the root system can supply, the plant is under water stress, which limits growth and survival. Carbon dioxide uptake, which is widely used as a measure of photosynthetic capacity and is a good indicator of the potential of the plant to survive and grow, will also be measured. A comparison of values across the hydrologic gradient may indicate at which point each species experiences stress due to either drought or water-table changes.

    Measuring the physiological response of vegetation

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  • Landscape Models

    The models developed as part of the species, community, and ecosystem-process field studies will be translated into GIS-based models that will be used to estimate the effects of hydrologic changes across the landscape of the study areas. The GIS-based species and community gradient models will be used to assess the landscape-scale distribution of community types and individual species and their response to changes in hydrologic regime. The ecosystem-process landscape models will be used to estimate water stress and photosynthesis under different hydrologic-regime scenarios. The goal is to develop models that can be applied throughout the Pinelands area.

    Upland-wetland gradient

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  • Build-out and Water-demand

    Knowledge of current and future water-supply demands is necessary to evaluate the long-term sustainability of the Pinelands ecosystem. This information will be obtained by completing a build-out and water-demand analysis. The central questions to be addressed concern the rate at which population and dwelling units will be expected to grow within the Pinelands, predicted development patterns at build-out, and current and future water-supply demands.

    Land use

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  • Data Management and Data-analysis Coordination

    A project-wide data management system will provide a centrally administered long-term repository for Kirkwood-Cohansey Project data that can be served via Internet access to study-team members and the public. Data-sharing needs among researchers, data-management objectives, data types, and linkages between data types will all be identified and incorporated in the database design. Data products will need to be made available for efficient access. Data-analysis methods used to develop models resulting from the different ecological studies must also be coordinated to ensure consistency among the studies and compatibility with the landscape-level models.

    Kirkwood-Cohansey Project Cooperators meeting

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  • Final Reports and Publications

    Bunnell, J. F. and J. L. Ciraolo. 2010. The potential impact of simulated groundwater withdrawals on the oviposition, larval development, and metamorphosis of pond-breeding frogs. Pinelands Commission, New Lisbon, New Jersey, USA. (click here)

    Ehrenfeld, J. G., and S. Yu.  2010.  Nitrogen dynamics study final report.  Part II. Dynamics of nitrogen under field conditions.  Rutgers University, New Brunswick, New Jersey, USA. (click here)

    Laidig, K. J. 2010. The potential impact of simulated water-level reductions on intermittent-pond vegetation. Pinelands Commission, New Lisbon, New Jersey, USA.  (click here)

    Laidig, K. J., R. A. Zampella, A. M. Brown, and N. A. Procopio. 2010. Development of vegetation models to predict the potential effect of groundwater withdrawals on forested wetlands. Pinelands Commission, New Lisbon, New Jersey, USA.  (click here)

    Laidig, K. J., R. A. Zampella, and C. Popolizio. 2010. Hydrologic regimes associated with Helonias bullata L. (swamp pink) and the potential impact of simulated water-level reductions. Pinelands Commission, New Lisbon, New Jersey, USA.  (click here)

    Lathrop, R. G., Y. Zhang, Z. Maio, and J. Bognar.  2010.  Landscape level modeling of the potential effect of groundwater-level declines on forested wetlands in the New Jersey Pinelands.  Rutgers University, New Brunswick, New Jersey, USA.  (click here)

    Procopio, N. A. 2010. The effect of streamflow reductions on aquatic habitat availability and fish and macroinvertebrate assemblages in coastal plain streams. Pinelands Commission, New Lisbon, New Jersey, USA.  (click here)

    Bunnell, J. F. and J. L. Ciraolo.  2010.  The potential impact of simulated ground-water withdrawals on the oviposition, larval development, and metamorphosis of pond-breeding frogs.  Wetlands Ecology and Management 18:495-509. (click here)

    Charles, E. G. and R. S. Nicholson. 2012. Simulation of groundwater flow and hydrologic effects of groundwater withdrawals from the Kirkwood-Cohansey aquifer system in the Pinelands of southern New Jersey. U.S. Geological Survey Scientific Investigations Report 2012-5122, 219 p. (click here)

    Ehrenfeld, J.G. and S. Yu. 2012. Patterns of nitrogen mineralization in wetlands of the New Jersey Pinelands along a shallow water table gradient. American Midland Naturalist 167:322-335. (click here)

    Kennen, J. G. and M. L. Riskin.  2010.  Evaluating effects of potential changes in streamflow regime on fish and aquatic-invertebrate assemblages in the New Jersey Pinelands: U.S. Geological Survey Scientific Investigations Report 2010-5079, 34 p. (click here)

    Laidig, K. J.  2012. Simulating the effect of groundwater withdrawals on intermittent-pond vegetation communities.  Ecohydrology 5:841-852. (click here)

    Laidig, K. J., R. A. Zampella, and C. Popolizio. 2009. Hydrologic regimes associated with Helonias bullata L. (swamp pink) and the potential impact of simulated water-level reductions. Journal of the Torrey Botanical Society 136:221-232. (click here)

    Laidig, K. J., R. A. Zampella, A. M. Brown, and N. A. Procopio.  2010.  Development of vegetation models to predict the potential effect of groundwater withdrawals on forested wetlands.  Wetlands 30:489-500. (click here)

    Procopio, N. A.  2012. The effect of streamflow reductions on aquatic habitat availability and fish and macroinvertebrate assemblages in coastal plain streams.  Ecohydrology 5:306-315.

    Sumner, D. M., R. S. Nicholson, and K. L. Clark. 2012. Measurement and simulation of evapotranspiration at a wetland site in the New Jersey Pinelands. U.S. Geological Survey Scientific Investigations Report 2012-5118, 30 p. (click here)

    Walker, R. L., P. A. Reilly, and K. M. Watson.  2008.  Hydrogeologic framework in three drainage basins in the New Jersey Pinelands, 2004-06:  U.S. Geological Survey Scientific Investigations Report 2008-5061, 147 p. (click here)

    Walker, Richard L.,  R. S. Nicholson, and D. A. Storck.  2011.  Hydrologic Assessment of Three Drainage Basins in the Pinelands of Southern New Jersey, 2004-06.  U.S. Geological Survey Scientific Investigations Report 2011-5056, 145 p.  (click here)

    Yu, S. and J. G. Ehrenfeld.  2009.  The effects of changes in soil moisture on nitrogen cycling in acid wetland types of the New Jersey Pinelands (USA).  Soil Biology and Biochemistry 41:2394-2405. (click here)

    Zhang, Y., Z. Miao, J. Bognar, and R. G. Lathrop Jr. 2011.  Landscape scale modeling of the potential effect of groundwater-level declines on forested wetlands in the New Jersey Pinelands.  Wetlands 31:1131-1142.

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