Data collected at our 80+ monitoring sites in each of the 52 subwatersheds (HUC-14s) in the North and South Branch Raritan region (WMA8) is used by NJ Department of Environmental Protection (NJDEP) and US Environmental Protection Agency (EPA) to determine if water quality is meeting the standards required under the federal Clean Water Act.  Our data are also used to determine the antidegradation classification of streams in the Upper Raritan, many of which are category 1 (C-1) waters of extremely high quality and ecological significance.  In addition, our stream data allows our science staff and partners from academic institutions to analyze the causes of impairment. Check out our report on long-term trends in water quality in our streams and see our annual Watershed Report Card and learn more about the health of our streams now.

Each spring, we invite interested members, friends and the public-at-large to become involved in our stream monitoring program. Volunteers attend a training session that includes classroom lessons and an on-the-water demonstration with practice time. Volunteers learn how to conduct a visual assessment of a stream segment, how to properly take measurements of stream flow and other conditions, how to collect a stream sample, and how to complete the necessary paperwork. Volunteers typically work in teams, with three to four individuals per team. Each team selects the site(s) they wish to monitor, and we pair up volunteers according to the streams they are most interested in studying. Teams select the date and time for their monitoring session within the period between June 1st to 30th (this time frame represents typical summer stream flow). We provide all necessary equipment. Once at their site, volunteers follow the protocol they learned at the training session. The protocol is derived from the U.S. Environmental Protection Agency’s Rapid Bioasssessment Protocols for Use in Streams and Wadeable Rivers: Periphyton, Benthic Macroinvertebrates, and Fish Second Edition. Monitoring each site usually takes from one to one-and-a-half hours. Our quality assurance/quality control measures are rigorous — they include an annual review of practices, thorough training of volunteers and audits of data and procedures by the New Jersey Department of Environmental Protection.

Biological Assessments: To collect a biological sample, volunteers use a net to perform a “kick” in the stream, disturbing the benthic habitat in a particular riffle so that all cobble, sand and debris flow into the net. Volunteers sort through the collected debris to remove all benthic macroinvertebrates and preserve them in a jar of ethyl alcohol. The preserved specimens are sent to a certified laboratory to identify the benthic macroinvertebrates down to the genus level. We then calculate a High Gradient Macroinvertebrate Index (HGMI) score and rating (excellent, good, fair or poor) for each site. HGMI is derived from many metrics of macroinvertebrate population assemblage, including taxa richness, presence and proportion of sensitive species and functional feeding groups, and more. Click here for more information on how the impairment scores are calculated.

Visual Habitat Assessments: Volunteers assess and record a wide range of information such as stream characteristics, weather conditions, land use patterns, water uses and the suitability of the surrounding habitat for wildlife. Volunteers also measure air and water temperature and calculate stream flow. We use a Habitat Score Sheet developed by the EPA to determine this habitat suitability, which includes assessment parameters related to erosion, riparian vegetation presence and structure, streambed characteristics, and more.

Chemical Testing: RHA collects baseline data on all of our permanent stream monitoring sites in July of each year. We assess the concentration of nutrients and other ions (nitrogen, phosphorus, chloride, and conductivity), as well as other important water quality parameters (temperature, dissolved oxygen, pH). These measurements give us an important view of the quality of the water for aquatic life, and can also indicate the impact of local pollution.

Raritan Sentinel Climate Stations: In 2021, RHA deployed 5 Mayfly Enviro-DIY climate stations equipped with Conductivity, Depth and Temperature (CDT) sensors to measure and transmit data every 15 minutes to RHA’s Climate Dashboard. These continuous data allow us to assess the impacts of climate change, particularly major storm events and air temperature changes, on stream conditions, as well as how resilient these streams are to shifts in climate.

• RHA Long-term Trend Analysis
• Water Quality Report Card | Metadata
• Stream Monitoring Map
• Bacteria Monitoring Map
• Other RHA Maps and Reports

Data Use & Attribution: Our data are publicly accessible via our Stream Monitoring Map and upon request to support transparency, education, and informed decision making. While the data is publicly available, it remains the property of RHA. Use of our data is encouraged but must include clear attribution to Raritan Headwaters Association. Submission, redistribution, or deposition of our data into other agencies, organizations, or external repositories requires prior written approval from RHA. This helps ensure appropriate context, accuracy, and responsible stewardship of the data. If you are interested in using or publishing our data more broadly, please contact us. We are always happy to discuss potential collaborations.

For more information contact Benjamin Harris, RHA’s Watershed Scientist, at (908) 234-1852, ext. 315, or bharris@raritanheadwaters.org.

Pollutants enter the water environment from two main types of sources.

Point Sources of Pollution

A point source is a single, identifiable source of pollution, such as a pipe or a drain. Industrial wastes, municipal treated wastewater, and stormwater are commonly discharged to rivers in this way. High risk point source waste discharges are regulated by the New Jersey Department of Environmental Protection (NJDEP) and US Environmental Protection Agency through regulations and permits. To report pollution, call the NJDEP Pollution Hotline.

Nonpoint Sources of Pollution

Non-point sources of pollution are often termed ‘diffuse’ pollution and refer to those inputs and impacts which occur over a wide area and are not easily attributed to a single source. They are often associated with particular land uses, as opposed to individual point source discharges.  Nonpoint source pollution is the main source of most pollutants in our surface and groundwater and current stormwater regulations, green infrastructure and river friendly best management practices (BMPs) are being implemented on a large scale to control these sources.  River Friendly Resident, School, Business and Farm Programs are available to help guide practices to improve and protect water quality.  RHA’s Resource Hub also provides guidance on understanding stream water quality science as well as details on the part we play as individuals and communities in protecting and restoring our watershed.

Urban land use

In our urban areas rainfall run-off as stormwater is one of the major nonpoint sources of pollution impacting the water quality of our waterways. Stormwater from street surfaces and buildings (also known as “impervious surfaces” because water cannot infiltrate) is often contaminated with car oil, road salts, fertilizers and herbicides from lawns, bacteria from animal waste and soil, and sediment run-off from construction sites and eroding streams.  In urban industrial areas, stormwater may contain chemical contaminants.

In some outer-urban and urban fringe areas where sewer lines are not available, septic tanks and other onsite wastewater management systems are often in place. Seepage and surface runoff from septic tank effluents are also non-point sources of pollution to streams and groundwater. These septage effluents typically contain heavy concentrations of fertilizing nutrients, which can lead to freshwater eutrophication and subsequently harmful algae blooms (HABs).

Raritan Headwaters offers a seminar series, Watershed Tools for Local Leaders, to impart expertise to municipal officials and local environmental champions on various topics related to controlling nonpoint pollution and other measures to protect water quality and quantity.  Visit the page to find resources from past seminars on a variety of topics as well as see the schedule of upcoming workshops.

Agricultural land use

In farming areas nonpoint sources of pollution include pesticides, fertilizers, animal manure and soil washed into streams in rainfall runoff. Where stock are given access to stream banks they may foul the water and accelerate erosion.

Forestry land use

Forestry operations may contribute to non-point source pollution of streams by increasing soil erosion and sediment run-off.

Addressing Nonpoint Sources of Pollution

Non-point source pollution is often more difficult to control than point source pollution. In urban areas minimizing stormwater runoff and adequate street cleaning are some important measures, while in farming and forestry areas, soil conservation practices and the controlled application of pesticides and fertilizers are necessary if pollution of waterways is to be avoided.  To learn more about what you can do to control nonpoint source pollution visit our River Friendly page.