Vol. 6 No. 1 Summer 1998
A Newsletter About New Jersey's Water Quality Programs

The DEP and the United States Geological Survey (USGS) have cooperatively operated the Ambient Stream Monitoring Network since the 1970s. The data from this network have been used to assess the quality of freshwater streams and sediments. Although the network was sufficient to assess general status and trends, changes were needed to provide data for water quality indicators and watershed management. The new network, which was designed by a DEP and USGS interagency committee, has been operating since the fall of 1997. By using several different types of monitoring stations within each of the state's 20 watershed management areas, the new Ambient Stream Monitoring Network is designed to answer several important questions about surface water quality as follows: What is natural ("pristine") water quality? How does land use affect water quality? What is the status of water quality statewide? What is the overall water quality in each watershed management area? What if a problem arises? What parameters are monitored? What are the benefits of the new network? Surface Water Quality Network Map

What is natural ("pristine") water quality? To characterize water quality in natural settings, without pollutant inputs from sewage treatment plants, septic systems or stormwater runoff, reference stations have been established in the four physiographic regions (Valley and Ridge, Highlands, Piedmont, Coastal Plain) of the state. The six reference stations are located in parks and undeveloped areas. Data from these stations will be used to evaluate degradation in developed areas and to provide additional data to support surface water quality standards.

How does land use affect water quality? To characterize the effects of land use on water quality, 40 land use indicator stations have been established statewide. These stations were selected to monitor the two dominant land uses within each of the state's 20 watershed management areas. Drainage area size and percent of urban, agricultural, and forest were evaluated to select these stations. The biological health of many land use indicator stations is monitored through the DEP's Benthic Macroinvertebrate Monitoring Network. These data will provide insight into the biological effects of chemical pollutants, and the effects of nonpoint sources from dominant land uses on chemical and biological water quality.

What is the status of water quality statewide? To provide a strong statistical basis for estimating statewide water quality indicators, 40 status stations have been established. Two stations, from the set of 771 Benthic Macroinvertebrate Network stations, were selected at random in each of the state's 20 watershed management areas. This random selection process will be repeated each year to increase spatial coverage. These stations will also provide data at an ever increasing number of locations, and can potentially identify problems that were not identified through fixed-station monitoring. Because these stations were randomly selected, nine statewide status stations are also being sampled for another purpose (i.e., land use indicator station).

What is the overall water quality in each watershed management area? One integrator station has been located at the downstream end of each watershed management area. These stations will be used to characterize the combined effects of pollutants from all land uses and point sources that are transported down the river. Data collected at integrator stations (at or above head of tide), and tidal stations will be used to assess pollutant transport to back bays.

What if a problem arises? There are watershed reconnaissance stations that can be sampled each year to address specific issues or questions that are not addressed through other stations. For example, the watershed reconnaissance stations could be used to investigate the causes of impairment at benthic macroinvertebrate stations, provide preliminary watershed assessments, investigate point source impacts, and support the planned air deposition monitoring network. These stations will be selected each year based on DEP program needs. The number of stations and sampling frequency will reflect the data needs; funding is available for about 40 sampling events per year.

Bacteria, which was previously monitored throughout the year, will now be monitored only during the summer to provide a better assessment of "swimmability."

What parameters are monitored? Chemical and bacterial parameters are monitored in the network, and several significant changes in parameters have been implemented. Bacteria, which was previously monitored throughout the year, will now be monitored only during the summer to provide a better assessment of "swimmability." Dissolved oxygen was monitored only during the day (not at the lowest part of the diurnal cycle). Diurnal data will be collected gradually by several dissolved oxygen meters that record data for 24 hours. Nutrients, suspended solids and metals will continue to be monitored. The network has been significantly expanded to monitor pesticides currently in use and volatile organic chemicals at six reference stations and 40 statewide status stations. Stations will typically be monitored seasonally, four times per year.

The network now includes 115 stations, up from 79 stations, and spatial coverage will be further improved as new statewide status stations are monitored each year. The added flexibility afforded by reconnaissance sampling will facilitate proactive data collection as issues arise. To ensure continuity, monitoring results and design effectiveness will be evaluated each year to effect gradual improvements, rather than major shifts. For the next several years, trends will be available only for the 41 stations carried over from the previous design. Status results will be available from all stations in early 1999.

For more information about the state's monitoring network, please contact Tom Vernam, Water Monitoring Management, at (609) 292-0427, or Karen Schaffer, Division of Science and Research, at (609) 292-9692.