Primary purpose
To assess watershed/wetland integrity and potential impacts effecting the long term sustainability of wetland systems, by using a GIS and watershed-level landscape approach. Designed to enable the Pinelands Commission to complete a comparative assessment of all Pinelands watersheds and associated wetlands. When completed, the assessment can provide guidance for policy and regulatory decisions concerning site-specific wetland buffer distance.
Expertise needed
Professional(s) who have training/experience in New Jersey Pinelands wetlands and GIS development are required to implement the method. Once the wetlands are classified in a study area, no expertise is required of the users of the data.
Applicable habitat types
Wetlands in the New Jersey Pinelands (non-tidal freshwater).
Categories assessed
Two aspects of wetlands systems are addressed: watershed integrity and potential impacts.
Procedure
The user(s) delineates drainage areas (units) and calculates the following for each: final watershed integrity score (WIS) and final drainage unit’s potential impact score (PIS). The scores are calculated by following steps outlined in a table. For example, four landscape indexes/scores, including the land use score (LUS), are used to assess WIS. Calculating the LUS requires delineating 100 m wide concentric upland zones, weighting zones according to drainage areas and position relative to wetlands, rating the concentric zones by referring to a previously prepared rating schedule, and summing the weighted ratings of each concentric zone. The approach for calculating each landscape index/score differs. The NJ Watershed Method uses existing or newly developed digitized data. Analyses are done with a PC spread sheet program. Once the evaluation is completed for all drainage units, the WIS and PIS for each are displayed on maps.
Key Terminology
Ecological integrity: definition not provided.
Final drainage unit potential impact score (PIS): score indicating potential impact of an individual drainage unit that considers potential impacts from all upstream drainage units.
Final drainage unit watershed integrity score (WIS): score indicating watershed integrity of an individual drainage unit that considers upstream and downstream conditions.
Landscape indicators: actual data or measurements used to provide an approximation of landscape index/score (e.g., pH is an indicator used to calculate the surface water quality score).
Landscape indexes/scores: indexes that characterize ecological processes at the landscape scale. Landscape indexes used to assess watershed integrity include: land use score, surface water quality score, ground water withdrawal score, and biological diversity score. Landscape indexes used to assess potential impacts include: future land use pattern score, transitional soils score, and basin and wetland dimension score.
Potential impacts: definition not provided.
Primary drainage unit potential impact score (PISo): score indicating potential impact and reflects local conditions within an individual drainage unit.
Primary drainage unit watershed integrity score (WISo): score indicating watershed integrity and reflects local conditions within an individual drainage unit.
Output
Measures of ecological integrity and potential impacts of watersheds and associated wetland systems.
Contact person
Robert Zampella, Pinelands Commission, P.O. Box 7, New Lisbon, NJ 08064 phone: (609) 894-9311 ext. 6544; fax: none; e-mail: zampella@njpines.state.nj.us
Estimated time to assess 1 acre site
Total 320 hours per landscape unit (i.e., New Jersey Pinelands).
320 hours [Months of work]: Delineate drainage units (step 1), evaluate watershed integrity (step 2), and evaluate potential impacts (step 3).
Comparison of habitat types
Cannot directly compare individual wetland areas. Could enable direct comparison of watersheds within the New Jersey Pinelands, if an analysis of all Pinelands wetland systems is completed. The completed demonstration project can be used to compare watersheds within one portion of the Pinelands.
Use as guide to design
The NJ Watershed Method should not be used as a guide to design, but may be useful in guiding site selection. It is a watershed-level procedure that assesses ecological integrity and potential impacts within drainage areas. It does not address or provide information on site specific elements important to design. Some of the GIS data may be useful for selecting restoration/creation sites. For example, the potential impact score (PIS) could be used to identify preferred drainage areas if there is a desire to place a wetland in an area with a low impact potential. Also, the water quality score may be useful in identifying drainage areas with water quality that may jeopardize wetland restoration/creation. Alternatively, a low water quality score may be useful for identifying drainage areas that would benefit from restoration/creation.
Related procedures
None.
Extent of use/field testing
The NJ Watershed Method was a demonstration project and has not been used in the NJ Pinelands. Presently the author is conducting research on the relationship between wetland and aquatic attributes (e.g., fish communities, stream vegetation, amphibian communities, palustrine forests, water quality, and stream discharge) and land use disturbance. This work is directed toward developing a distance-weighted flow-path model (rather than the buffer approach used in the NJ Watershed Method) to estimate land use impacts on particular wetland sites (Pers. comm.: Robert Zampella, Pinelands Commission, July 13, 1998).
Proposed future revisions
None planned. The author recommends revisions before implementation (Pers. comm.: Robert Zampella, Pinelands Commission, July 13, 1998).
Key Reference
Zampella, R.A., R.G. Lathrop, J.A. Bognar, L.J. Craig, and K.J. Laidig. 1994. A Watershed-based Wetland Assessment Method for the New Jersey Pinelands. Pinelands Commission, New Lisbon, NJ. 77 pp.