Raritan Watershed

Description of Watershed

The Raritan River Basin is located in north-central New Jersey, approximately midway between New York City and Philadelphia. The Raritan Basin is the largest river basin located entirely within the State of New Jersey. The Basin covers approximately 1,100 square miles (699,542 acres) and includes parts of seven counties (Hunterdon, Mercer, Middlesex, Monmouth, Morris, Somerset and Union counties) and all or part of 100 municipalities.

Major potable water systems within the Basin include Spruce Run Reservoir, Round Valley Reservoir and the Delaware and Raritan Canal. The Raritan Basin provides water to approximately 1.2 million people in central New Jersey, including drinking water, irrigation water for farms, nurseries and golf courses, and processing water for industries. In addition, the Basin is also used for many recreational activities including boating, fishing and hiking and provides habitat for many aquatic and terrestrial organisms.

Major waterways in the Basin include the North Branch and South Branch of the Raritan River (known collectively as the Upper Raritan River), the Lower Raritan River, South River, Green Brook, Lawrence Brook and the Millstone River, along with all their many feeder streams. The Delaware & Raritan Canal, which brings water from the Delaware River to the eastern part of the Basin, augments Raritan water supplies.

Today, land uses along the main stem of the Raritan River consist primarily of urban and suburban developments with a number of industrial and commercial centers. Land uses along the South Branch of the Raritan River are mostly agricultural, but suburban and commercial developments are increasing at a rapid rate. Land use along the North Branch of the Raritan River is primarily rural and consists of large woodland tracts and agricultural lands. Commercial and residential areas are scattered along the North Branch of the Raritan River, and development is increasing along major roads. Land uses along the Millstone River consist primarily of suburban developments and a number of scattered agricultural areas. Land uses in the northern portion of the Basin consist primarily of residential development, with large areas devoted to public water supply and outdoor recreation.

Over the past few decades many of the dairy located in the western portions of the Basin have been lost and the land rapidly developed, although many farms have converted to non-livestock uses and are still in operation. Corporate parks, specializing in research and development, have become common, especially in the areas surrounding Princeton and New Brunswick. Residential developments have replaced old fields and pastures in ever expanding suburbs. Parks, forests and small areas on steep rocky ridges contain the remnants of remaining open space.

Land Use Data and Maps

Based on 1995 Census of Agriculture

Common Resource Areas

CRA 148.NJ1 Northern Piedmont

The Northern Piedmont is characterized by uplands of rounded hills, low ridges, relative high relief, and narrow valleys underlain by metamorphic rock and Triassic lowlands characterized by wide undulating ridges, broad nearly level valleys, limited local relief, and a mosaic of farms and houses. Upland soils were derived from residuum and are mostly Alfisols containing a moderate to high level of subsoil base saturation. Fall Zone occurs near the eastern edge and is characterized by areas of high stream gradient, exposed bedrock, islands, falls, and a mixture of metamorphic and sedimentary rock. Deep Ultisols and Inceptisols are common and have developed from residuum. Triassic lowland soils are derived from quartzite are commonly stony and are often forested. Chrome soils from serpentinite occur locally and are low in calcium and high in magnesium, chromium, and nickel.

CRA 149.NJ1 Northern Coastal Plain

A Rolling Coastal Plain that is a hilly upland with narrow stream divides, incised streams, and well-drained loamy soils. Soils are naturally low in nutrients and require liming and fertilizing to be productive for agricultural crops. Ultisols are common and have a mesic temperature regime.

Grass/Pasture/Hay Lands

• Complications related to overgrazing and/or winter grazing include poor pasture condition, soil compaction, and water quality issues.
• Control of noxious and invasive plants is an ever increasing problem.
• The number of small, part-time farms is increasing. They are less likely to adapt conservation due to lack of awareness and economics of scale.

Row & Perennial Crops (grain/vegetables/nurseries)

• Residue, nutrient and pest management are needed to control erosion and protect water quality.
• Conservation buffers are needed to protect existing high water quality and trout habitat.

Forest

• The NJ Highlands Act encourages preservation of forested lands in the northwest portion of the watershed.
• As a result, there will be increasing focus on water quality and forest productivity issues in this area.

Selected Resource Concern for Tier II contracts: Since the predominant water quality concern in the watershed is based on excess phosphorus in the surface water bodies, we have selected Excessive Nutrients and Organics in Surface Water as the additional resource concern for the Raritan Watershed.

Studies and Assessment Data

Completed Studies:

• Setting of the Raritan River Basin July 2000
• Landscape of the Raritan River Basin August 2002
• Surface Water Quality and Pollutant Loadings August 2002
• Surface Water and Riparian Areas of the Raritan River Basin September 2002

Completed Water Quality Assessments:

North & South Branch (Upper) Raritan surface water quality impairments:

• 36 sampling locations cited.
• Parameters ‘not attaining’: Phosphorus cited at 31% of locations; fecal coliform cited at 53%.         

Fecal coliform and total phosphorus are the major water quality concerns. Sources cited as likely contributors of fecal coliform are: leaking septic systems, faulty connections to storm or sanitary sewers, and wildlife, such as geese. Sources cited as likely contributors of phosphorus are permitted point source discharges and non point sources. In general, non-point source pollutants sediment and nutrients from agriculture are a “suspected but unconfirmed” problem in the watershed.

Agricultural pesticide use was on the increase in the South Branch in the period 1994-1997.

Lower Raritan surface water quality impairments:

• 48 sampling locations cited.
• Parameters ‘not attaining’: Phosphorus cited at 19% of locations; fecal coliform cited at 25%.

Agricultural pesticide use trend decreased in the period 1994-1997. Agriculture is not cited as a source of any other pollutants, which instead are attributed to permitted point source and urban-suburban nonpoint sources.

Millstone River surface water quality impairments:

• 46 sampling locations cited.
• Parameters ‘not attaining’: Phosphorus cited at 22% of locations; fecal coliform cited at 26%.

Agricultural pesticide use trend decreased in the period 1994-1997. Permitted wastewater facilities are cited as a potentially significant point source. Non-point sources of pollution are cited as mostly coming from suburban development. Agriculture is cited as a probable predominant source in specific regions of the watershed.
It is interesting to note that in the majority of cases in all three WMAs, phosphorus and fecal coliform were not attaining at the same sampling locations.

Also, total concentration and number of pesticide compounds increased with increasing percent agricultural land use.

Riparian Areas:

From the ‘Surface Water and Riparian Areas of the Raritan Basin’ report-

“Riparian area results for the Upper Raritan show that 32% of the historical riparian land cover has been converted to agricultural (16%) and urban (16%) land uses by 1995. The Lower Raritan has had approximately 31% of its historical riparian area converted to agricultural (4%) and urban (27%) land uses by 1995, while the Millstone has had 28% of its historical riparian areas converted to agricultural (12%) and urban (16%) land uses.

“The greatest conversions have occurred in Tewksbury Township in the Upper Raritan, along Chambers Brook in Somerville and Bridgewater Township, along Green Brook and Bound Brook, along tributaries to the mainstem of the Raritan River near New Brunswick and Franklin Township (Somerset County), in the highly urbanized Woodbridge/Edison Township area, along the headwaters of Deep Run in Marlboro and along the headwaters of the Matchaponix Brook in the vicinity of Manalapan Township and Marlboro Township in the Lower Raritan. In the Millstone, extensive conversions have occurred in Hillsborough Township, Cranbury and Plainsboro Townships. Other significant conversions in the Millstone have occurred along the D&R Canal and the Millstone River in Princeton Township, in the vicinity of the Route 1 corridor, and in the vicinity of Hopewell Township.

“Despite federal, state and local regulations that have been established to protect surface waters and riparian areas, continued degradation of habitats and conversion of these natural features to other land cover types is evident throughout the Raritan Basin. Projects such as stream bank restorations, wetland creation and enhancement, and flood mitigation help restore degraded habitats, but efforts to prevent further destruction or loss of these habitats need to be established. More stringent regulations such as the proposed wetlands regulations and the water quality and watershed management rule and proper planning may guide future growth patterns, but more needs to be done to maintain and improve the quality and quantity of these ecosystems.”

Funded Studies:

• A Regional Stormwater Management Plan For the Pleasant Run and Watershed (Readington Township)
• A Proposal to Prepare a Regional Stormwater Management Plan for the Sourland Mountain Watershed (East Amwell Township)
• A Regional Stormwater Management Plan for the Devils, Shallow, Cedar, and Cranbury Brooks Watershed, Raritan River Basin (Middlesex County Planning Department)
• Stormwater Management Plan for the Cedar Grove (Al's) Brook Watershed (Township of Franklin and NJ Water Supply Authority)
• Mulhockaway Creek Watershed Study (New Jersey Water Supply Authority)

Census and Social Data

Number of Farms According to Farm Size

Number of Farms:  3567 Number of Operators:  4008 Full-Time:  911 Part-Time:  3097 Based on 1995 Census of Agriculture County Data

Estimated Willingness and Ability to Participate in Conservation: Moderate to High

Generally, agricultural land users in the watershed are well educated and have a positive stewardship attitude. They continue to farm under less than ideal conditions – a high level of regulatory oversight by the state and sensitivity to conflicts with non-farm neighbors. They normally understand the benefits of conservation and are actively engaged in agricultural organizations that use a proactive approach to both educate urbanites and promote conservation practices on farms of all sizes.

There are a growing number of part-time and/or new farmers whose primary occupation is not agriculture. Although normally willing conservation advocates once informed, the main concern is a lack of awareness by this group of the availability of technical resources and programs.

Evaluation of Social Capital: Moderate to High

There is strong “home-rule” leadership at the municipal level across New Jersey, with most municipal officials experienced in working within and between local communities to solve problems. Many farmers serve on municipal planning, zoning, and other local and county committees. Additionally, farmers in the Raritan Basin have organized a multi-county agricultural committee to review and respond to actual and perceived resource concerns, state and local legislative initiatives, and resolve farmer/non-farmer conflicts.

The type of agriculture in the watershed is changing from the traditional large grain or combination grain and livestock farms of the 1950’s. Most new or continuing operations are moving toward small acreage high value crops, such as nursery, equine, and vegetables.

The average farm size for the watershed is 72 acres. More than 75% of the farms are at or below this acreage, which means there are few very large traditional farms left that are still viable. Much of this change is due to economics and development. As land is converted to non-agricultural uses, farmers find it more difficult to sustain the land base necessary for more traditional type operations. And the high land values in New Jersey make it difficult for farmers to purchase more land to offset loss of rented land to these other uses.

Progress Data

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Last Modified: March 07, 2007