A million persons in eastern New Jersey get their drinking water from the Delaware River via the Delaware and Raritan Canal. That water is polluted with fertilizer, fecal coliform and sediment that drains into the Canal with surface runoff after rainstorms and snowmelt. Dredging the Canal and purifying the water costs over $1 million annually. 60% of the surface runoff entering the Canal comes from the Lockatong and Wickecheoke Watersheds. For the past three years, the New Jersey Water Supply Authority (NJWSA) has been studying these watersheds and drafting a Protection and Restoration Plan. The results of that study will be presented on Thursday, March 5 at 6:00 PM at Prallsville Mill, on Rt. 29 in Stockton. The public is invited to attend and ask questions.
The NJWSA’s Lockatong and Wickecheoke Watersheds Protection and Restoration Plan recommends implementation projects for remediation of nutrient, bacterial and solids loadings, and stream flow regimes. In layman’s terms, the problems identified by NJWSA are violations of state surface water quality standards for: phosphorous (an ingredient of fertilizer); fecal coliform bacteria (which NJWSA believes comes from failed septic systems rather than livestock, deer or geese feces); high levels of sediment, and high levels of runoff entering the stream and collapsing the streambanks. Collapsing streambanks have been identified as by far the largest contributor of sediment in stream water. Therefore, the NJWSA is looking for ways to reduce runoff, with the logical expectation that this will reduce the damage to streambanks and thus the amount of sediment.
The NJWSA estimates that about 16,000 tons of sediment flows out of the two watersheds each year into the D&R Canal. A dredger operates throughout the year at Prallsville Mill in Stockton removing the soil, gravel and stone that washes downstream from Delaware, Kingwood, Franklin and Raritan Townships. The intuitive link between runoff in the watersheds and sediment in the water is strengthened by the piles of sediment accumulating in Canal locks after heavy rains.
40% of the land in the Lockatong and Wickecheoke watersheds is devoted to agriculture, 30% is forest, 18% is wetlands, and 12% is urban land use, which includes residential, commercial and industrial property, and roads. Urban land use contributes disproportionately to runoff. The NJWSA estimates that the road system and associated roadside drainage pipes and ditches contribute 4,000 tons of sediment annually (including 400 tons of de-icer). But even more significantly, roads and ditches are very effective collectors of runoff, and they deliver it directly into streams, or into eroded ditches connected to streams. NJWSA found many examples of high volumes of runoff from ag fields entering roadside ditches. Also, homeowners are in the habit of asking the County and Township road departments to reduce flooding on their property, and the road departments do their best to oblige, with the result that downspouts, driveways, and ditches on private property are routed into roadside ditches. One goal of the NJWSA implementation projects is to reduce improper connections, and to increase on-site recharge.
The NJWSA notes that 30% of the watersheds is forested, but that deer browsing and deer trails degrade the effectiveness of forest to recharge stormwater. Browsing prevents forests from regenerating. Trails become channels for runoff.
NJWSA’s Implementation Projects have recommendations tailored to every type of land use in the watersheds. They hope to elicit the cooperation of County and Township road departments, homeowners, and farmers. The NJWSA Program Committee will include the US Geological Service, Natural Resources Conservation Service, NJWSA, NJ Department of Environmental Protection, municipal representatives and professionals, New Jersey Conservation Foundation, Hunterdon County Soil Conservation District, and the Hunterdon County Engineering Department.
The proposed protection and restoration projects are listed in order of priority: 1 Rehabilitation of Conservation Lands; 2 Roadside Drainage – Retrofit Training; 3 Runoff Management Techniques Applicable to Both Public and Private Lands – Wetland and Rain Garden Controls; 4 Targeted Agricultural Assistance Program; 5 Updating Best Management Practices manuals for local conditions – with training for municipal officials; 6 Hydrogeologic Study – tracking groundwater recharge areas, available water supply, flow direction and seasonality, and water quality impact; 7 Streambank Stabilization; 8 River Friendly Farm Certification.
Background – Land Use
The NJWSA has been studying the watersheds for the past three years, taking water samples, measuring flows, examining land use, looking at fields, lawns and roads, reviewing historic rainfall patterns, sampling soils, studying farming practices, and watching road crews. The recommended implementation projects are all made with a consideration of existing land use practices and the effects these have had on watershed stability. NJWSA notes that the increased runoff that is destabilizing the stream banks has several causes: compacted soils, increased impervious cover and greater intensity storms. While NJWSA does not make the link in this report, greater intensity storms are one of the predicted consequences of global warming that are already being observed, and that are expected to worsen.
In considering Rehabilitation of Conservation Lands, NJWSA notes that decades of agricultural production involving extensive tillage and other field operations (mowing, tethering, baling) have caused soils to become compacted and lose their prior ability to retain and infiltrate rainwater. Evidence in the stream corridor indicates that even when water draining off ag fields is relatively clear, it has increased over the decades in volume and erosivity.
As a first step toward a remedy, NJWSA proposes taking 150 acres of conservation land not in active agriculture, breaking up the hardpan with a chisel plow, creating small crescent- shaped terraces to slow runoff, and planting warm-season grasses and woody vegetation. The anticipated benefits are a 25% – 40% decrease in runoff and increase in groundwater recharge. Sediment and flow reductions throughout the watershed will increase proportionately as this remedy is applied to more land.
Roadside Drainage Design / Retrtofit Training
The familiar problems associated with roadside ditches – increased volume of runoff delivered directly to streams – are to be addressed by training road departments in Better Management Practices. NJWSA recommends making annual training mandatory to ensure effective on-going emphasis for the design, construction and maintenance of roadside drainage ditches.
One possible loophole that could undermine the effectiveness of this program is that, under State law, the County road department is “self-certifying and self regulating”. Inclusion of the Department of Public Works Recertification Program at the Hunterdon County Engineering Office may enable a “business as usual” approach.
Targeted Agricultural Assistance Program
NJWSA recognizes that agriculture will continue to be a significant land use in the watersheds, and that it contributes to rural character. However, agriculture can contribute to the problems of sediment, bacteria and volume of runoff in the streams. “Erosion from agricultural operations results from non-conservation plowing, lack of riparian buffers, animals with direct access to streams, and over-grazing. Increased water temperatures result from poor riparian buffers exposing streams to sunlight.
Through its Integrated Crop Management service, Hunterdon County Soil Conservation District (HCSCD) has uncovered several prevalent trends in the county. HCSCD reports that “Many continually farmed tracts are over-limed with pH levels above optimum while others required lime, indicating that lime is applied without evaluation of its necessity for crop production. Optimizing pH levels maximizes nutrient availability and crop growth, while reducing the amount of nutrients in runoff. Phosphorous is usually found at or above optimal levels, but farmers still apply fertilizer that contains it. Potassium is seldom found at optimum levels, and is either very low or excessive. Manure is often applied without a soil test and without knowledge of the soil’s and/or crop’s ability to incorporate the nutrients. Use of herbicides and pesticides is typically based on the presence of a pest or weed rather than the economic and biological damage thresholds”.
The proposed solution is a voluntary program, at no cost to the landowner, aiming at nutrient management and integrated crop management. HCSCD would serve as the coordinator. The anticipated benefits are reduction of costs to farmers due to overuse of fertilizers, and reduction of nutrient and bacteria pollution. The HCSCD program has already resulted in reduction of lime, fertilizer and pesticide applications.
Although the Targeted Agricultural Assistance Program hopes to manage erosion, the above – mentioned advice on nutrients does not seem adequate to that goal. Easements to expand stream buffers, incentives to delay first mowing or to leave more ground cover through fall and winter, aid for deer – fencing to protect riparian plantings, are all methods that have been successfully implemented and could be a voluntary, and funded, part of a restoration plan for these watersheds.
Runoff Management Techniques Applicable to Public and Private Lands
The pilot project for this part of the restoration plan is in Kingwood Township Park on Union Road. The soil in the athletic field is severely compacted, and runoff is a problem. The adjacent stream is full of sediment. The proposed remedy is to retrofit the park with bioretention wetlands, rain garden stormwater control, and streambank revegetation. These projects will be done “in a manner that will be intended to encourage homeowners to copy them on their own lawns on a different scale”.
NJWSA notes under “Major Implementation Issues” that there will be a need for public outreach and education, via signage and brochures for people using the athletic field. “There may be occasional opposition to the increased maintenance at the site. Uneven microtopography will mean that field mowing and maintenance may become more labor intensive. Some may object to the more natural appearance and wetter conditions compared to the existing close-mowed turfgrass”.
This effort could have broad applicability. In Delaware Township there is a similar condition at the Delaware Township School. The drainage catch basin there was damaged by heavy rains in 2006. As the Kingwood Park project moves forward, the Delaware Township School Board may be able to learn something about remedying its stormwater runoff problems. DTS is not in the Lockatong and Wickecheoke Watersheds, so it is not a part of NJWSA’s Watershed Protection and Restoration Plan.
Streambank Stabilization Measures
A section of Lower Creek Road collapsed after Hurricane Floyd in 1999. Two other sections collapsed in the summer of 2006 after heavy rains. The collapsed sections were rebuilt at a cost of over $250,000. This is a good illustration of the common interest Delaware Township and the NJWSA have in protecting the watersheds. The money spent rebuilding washed out creek bank didn’t do anything to address the cause of the washout, which is historically high levels of runoff entering the streams.
Streambank stabilization measures, while important, are given a relatively low priority, after rehabilitation of conservation lands; roadside drainage – retrofit training; runoff management techniques applicable to both public and private lands – wetland and rain garden controls; and the targeted agricultural assistance program. This may be because, of the two problems facing NJWSA, sediment reduction and runoff reduction, the more fundamental is runoff, and bank stabilization is just a response to that problem. As the saying goes, an ounce of prevention is worth a pound of cure.
Nevertheless, NJWSA estimates that reduction of erosion along 300 feet of stream bank could result in the prevention of 90 tons of sediment each year. If the streambank stabilization could be targeted at sections where roads are in imminent danger of collapse, benefits to the Township would increase. This type of cooperative project could enhance the perception of a commonality of interests between NJWSA and the municipality.
River Friendly Farm Program may be Expanded
The River Friendly Farm program advises landowners and managers on ways to reduce runoff and prevent erosion on their lands adjacent to streams, while maintaining or enhancing the profitabliity of their farming operations. To date one farm in Delaware Township has applied for and received certification in this program. Currently the River Friendly Farm program operates only in the Raritan Basin – this includes the Third Neshanic watershed but not the Lockatong and Wickecheoke. The NJWSA report mentions the possibility of expanding the River Friendly Parm program to the Lock – Wick.
NJWSA performed a buildout analysis for the municipalities in the watersheds, estimating how many new housing units might someday be built under existing zoning conditions. Estimates indicate that farmland contributes more sediment per acre than housing does, but this is not to say that anybody wants to see all the farms developed for housing. Far from it: if they were, the percentages of impervious cover would increase dramatically, and if those new impervious surfaces are not managed properly to capture stormwater runoff flows, high flows will increase streambank erosion, thereby increasing sediment loads to the Canal. Current zoning in Delaware Township would allow a 220% increase in number of housing units in the watersheds, and a 480% increase in commercial acreage. Some 4,445 acres of ag land and forest would be converted to urban use in the two watersheds, under current zoning. In addition to voluntary targeted ag assistance and other programs, the NJWSA recommends continued participation in land preservation.
Whichever of these protection and restoration projects is implemented first, this important report marks the beginning of a long-term cooperative effort between NJWSA and local government agencies which stands to benefit all stakeholders in the watersheds.