Biological Assessment for Category One Upgrades

Category One waters are protected from any measurable changes in water quality because of their exceptional ecological significance, exceptional recreational significance, exceptional water supply significance, or exceptional fisheries resources.

To qualify as an exceptional aquatic community, waters must exhibit no impairment of the benthic macroinvertebrate community as measured by the Department's Standard Operating Procedures for Ambient Biological Monitoring Using Benthic Macroivertebrates, December 2007.

Benthic macroinvertebrates are primarily bottom-dwelling fauna easily viewed with the naked eye. These fauna are generally ubiquitous in freshwater and estuarine environments and play an integral role in the aquatic food web. Benthic macroinvertebrate assemblages are made up of species that constitute a broad range of trophic levels and pollution tolerances, thus providing strong information for interpreting cumulative effects. Insects (largely immature forms) are especially characteristic of freshwaters; other major groups include worms, mollusks (snails, clams) and crustaceans (scuds, shrimp, water fleas, etc.). Species comprising the in-stream community occupy various niches, based on functional adaptation or feeding mode (for example, predators, filter or detritus feeders, scavengers, etc.). Their presence and relative abundance is governed by environmental conditions (which may determine available food supply), and by pollution tolerance levels of the respective species. Benthic macroinvertebrate communities integrate the effects of short-term environmental variations and provide an ecological measure of fluctuating environmental conditions.

Since benthic macroinvertebrates have limited migration patterns, or a sessile mode of life, they are particularly well-suited for assessing site-specific ecosystem health. Sampling is relatively easy, requires few people and inexpensive gear, and has minimal detrimental effect on the resident biota.  This makes benthic macroinvertebrate assemblages good indicators of localized conditions. A benthic macroinvertebrate community that is not impaired is characterized by a diverse macroinvertebrate population, balanced taxa groups (i.e., no taxa are overly dominant), and a good representation of pollution-intolerant taxa.

Each benthic macroinvertebrate sample is collected using the methods described in the Department's Standard Operating Procedures for Ambient Biological Monitoring Using Benthic Macroivertebrates, December 2007. The Department uses these methods, as part of its assessment of aquatic life use attainment, to determine if the biological community is impaired. Prior to 2007, macroinvertebrate data were analyzed using a single index called the New Jersey Impairment Score or NJIS. In 2007, the Department changed from this single index method to assessment based on multimetric indices specific to each of three regions identified below:

1) high gradient streams above the Fall Line (a line separating the Piedmont from the Coastal Plain);

2) the Inner Coastal Plain streams; and

3) New Jersey Pinelands streams (waters contained within and just outside the Pineland Jurisdictional Area).

In each region, samples are analyzed to determine the number of individuals by genus and species. These data are then used to generate a multimetric assessment index that serves as a predictable measure of a biological community's response to environmental stress, including that created by pollution or habitat degradation.

In order to qualify as an exceptional aquatic community, for the purpose of Category One designation, the biological assessment results must indicate full attainment of the macroinvertebrate community.

The Department's Water Monitoring and Standards Program samples over 800 stations for benthic macroinvertebrates and in-stream habitat. Streams are sampled once every five years on a rotating basin schedule. A detailed description of the biological monitoring program and copies of resulting reports are available on the Department's Web site.

For waters where the Department has not yet sampled, data generated by other groups will be considered to support a Category One upgrade provided that the information has been or will be submitted pursuant to the Department's data solicitation notice for the development of the Integrated Water Quality Monitoring and Assessment Report (Integrated Report).  The Department will also consider data that meets the requirements specified for Tier D under the New Jersey Volunteer Monitoring Program.

For more information about Category One Waters, please contact the Bureau of Water Quality Standards and Assessment at (609) 777-1753.