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Implementation of Riparian Forest Buffer Systems for the Rancocas Watershed

M.C. Vodak & A.C. Pasquini

Rutgers University, USA.


The Forestry Extension Program of Rutgers University Cooperative Extension is leading a well-partnered effort to improve the water quality of the Rancocas Watershed through the control of nonpoint source pollution. The project is funded through a Section 319 “Nonpoint Source Pollution Control and Management Implementation Grant” administrated by the New Jersey Department of Environmental Protection. Two riparian forest buffers modeled on the United States Forest Service’s Three-Zone Buffer System have been established on two different sites within the watershed. The differences between the two sites chosen provide the unique opportunity to demonstrate the flexibility and range of design options for riparian forest buffers. Both sites incorporated local community and volunteer efforts and were important components of the buffer implementation. Both sites have also offered and continue to offer educational opportunities for municipal officials, farmers, other landowners, and the general public.


The Rancocas Watershed consists of 360 square miles (933 square kilometers) and includes parts of Burlington, Camden, Mercer, Monmouth, and Ocean counties in south-central New Jersey, in the northeastern United States (See Figures 1 and 2 in the Appendix.). The 1990 population of the Rancocas Creek Watershed was 690,000 and is projected to grow to 729,000 by the year 2040. The water demand of 101 million gallons (382 million liters) per day in 1990 is expected to increase to 135 million gallons (511 million liters) per day by 2040. Increases in population size, development, and water demand within the Rancocas Watershed require immediate water quality improvements that can be obtained through the implementation of riparian forest buffer systems.

The Rancocas Watershed has been cited as a priority watershed by the “Draft 1998 Identification and Setting of Priorities for Section 303(d) Water Quality Limited Waters in New Jersey” (NJDEP, 1998). Pollutants have resulted in water quality violations for pH, fecal coliform, lead, mercury, and total phosphorus, leaving the Rancocas moderately to severely impaired. Use impairments include primary contact for recreation, aquatic life support, and fish consumption. The New Jersey Department of Environmental Protection has had in place for some time a system for identifying and monitoring point source pollution discharges in the watershed, and, given the land use development patterns in the watershed, recognized the need to reduce nonpoint source runoff to enhance and maintain water quality within the watershed.

Riparian forest buffers offer one alternative for reducing nonpoint source pollution. Though only in recent years recognized as a pollution control technique, there has been a surge of interest in riparian forest buffers for controlling pollution. Recent research indicates that in many landscapes, forest buffers can be highly effective in trapping, filtering, and converting sediments, various nutrients, such as phosphorus and nitrogen, and other chemicals. Forest buffers also help to maintain the hydrologic and ecological integrity of stream channels and shorelines, and protect fish and other wildlife by supplying food, cover, and temperature control.

Targeting nonpoint source pollution control in the Rancocas Watershed, Rutgers University Cooperative Extension formed a partnership with the United States Natural Resources Conservation Service, North Jersey Resource Conservation and Development Council, Burlington Soil Conservation District, Rancocas Conservancy, Delaware Valley Regional Planning Commission, New Jersey Forest Service, and the United States Forest Service. The four goals established by the partnership were to: 1) inventory cover types of the Rancocas Watershed riparian zone to assure proper species and site selection; 2) control nonpoint source pollution resulting in future environmental and economic benefits; 3) raise awareness, advance knowledge, promote the preservation and adoption of riparian forest buffer systems in the Rancocas Watershed; and 4) ensure continued implementation and success by creating a system to share knowledge, ideas, and results regarding riparian forest buffer system management. To achieve these project goals, two buffers were designed and planted to demonstrate the riparian forest buffer model and an implementation process.

This paper discusses the selection and planting of two riparian forest buffers as a demonstration and educational tool targeted for school children, municipal officials, farmers, other landowners, professional resource managers, and the general public.

Procedure and Implementation

Riparian forest buffer systems are a proven best management practice for the control of nonpoint source pollution. An extensive list of supporting documentation that details the functions and extols the benefits of riparian buffers can be found in an annotated bibliography by Correll (1996). Similarly, research has shown that buffers can effectively reduce nitrates and phosphorus passing through from adjacent areas (Schultz et al, 1995; Ducnuigeen et al, 1997), as well as provide important ecological benefits (Lowrance et al, 1995). The Three-Zone Riparian Forest Buffer System promoted by the United States Forest Service (Welch, 1991) for controlling nonpoint source pollution and improving water quality was selected as a guide for implementing this riparian buffer project. This model calls for three zones that are individual in function but interact with adjacent zones to provide an effective buffer system (See Figure 3 in the Appendix.).

Zone 1 is an area of permanent woody vegetation immediately adjacent to the stream. Its purpose is to control erosion by stabilizing the stream bank. Favorable habitats for fish and other aquatic organisms are created through the production of leaf litter, woody debris, and lower stream temperatures due to shade and retention of dissolved oxygen. Zone 2 is a sustainable, managed forest adjacent to and upslope from Zone 1. Its purpose includes filtration, deposition, plant uptake, denitrification, and other natural processes that remove sediments and nutrients from surface runoff and subsurface flows. Selective harvesting should occur to remove sequestered nutrients (stored in woody biomass) while providing a potential source for economic gain for the landowner (Lowrance and Sheridan, 1985). Zone 3 is an herbaceous strip adjacent to and upslope form Zone 2. Its purpose is to convert runoff from concentrated flows to a uniform sheet flow. This facilitates the removal of coarse, suspended sediments and sediment borne pollutants. Grass filter strip studies have shown sediment trapping efficiencies to exceed 50% only when concentrated channeled flow is converted to shallow uniform sheet flow (Ducnuigeen et al, 1997). Using the Three-Zone Model, buffer width, as well as each zone width, can vary based on soil type, slope, and ownership.

A four-phase implementation plan was designed to achieve the project goals. In Phase 1, both naturally occurring forest buffers, as well as potential sites for restoring forest buffers, were inventoried and evaluated. Where natural buffers were present, buffer width, species composition, soil type, drainage characteristics, flood plain, and land use practice were noted. Potential restoration sites were georeferenced and mapped for possible forest buffer implementation. Recent aerial photography and available geographical information system (GIS) data for the watershed were the primary tools for this phase. Project partners, natural resource professionals, planning and municipal officials in the region, and others familiar and experienced with the watershed were also valuable resources for locating potential buffer restoration sites for the project. Two sites were selected for the project: Iron Works Park along the North Branch of the Rancocas Creek in the municipality of Mt. Holly, and the Coles Roberts Farm, a privately-owned farm in Southampton Township along a small tributary of Little Creek, a major tributary of the Southwest Branch of the Rancocas Creek.

In Phase 2, two three-zone, multi-species riparian forest buffer systems on the two sites selected in Phase 1 were planted and established. The Mt. Holly site, (approximately 2.0 acres (0.81 hectares)), was planted in Spring, 1999. The Roberts Farm site (approximately 1.5 acres (0.61 hectares)) was planted Spring, 2000. The design stage for each site included obtaining appropriate authorization from the respective owners for use of the site, inventory of native riparian plant species immediately up- and down-stream of the site, soil testing, and species selection for the design.

The Mt. Holly site. Located in a municipal park on the south side of the stream, the first 5 to 10 feet (1.5 to 3.0 meters) of the 15-foot-wide (4.5-meter) Zone 1 had existing trees, and no site preparation was required for additional plantings. Site preparation in Zones 2 and 3 (approximately 60 and 25 feet (18 and 7.5 meters) wide, respectively) was accomplished with a backpack sprayer application of ghyphosate followed by rototilling with a small farm tractor. Herbaceous and grass seed mixes, and 600 mostly container-grown trees and shrubs representing 50 different species were obtained from native plant nurseries in the southern New Jersey/southeastern Pennsylvania area. The seed mixes were combined with cat litter for more even distribution and were hand-planted by Rutgers and Mt. Holly personnel.

Two volunteer dates were arranged with the community for planting the trees and shrubs. Small wire flags were color-coded by species and placed in Zones 1 and 2 prior to the planting dates, indicating where each tree or shrub was to be planted. Flag placement (tree location) mimicked nature as closely as possible. A tractor and auger were used to dig holes next to each flag for planting the container-grown material. Volunteers from the community planted and mulched each tree and shrub. Volunteers included local high school students, cub scouts, members of local environmental groups, and neighboring residents. Rutgers personnel planted additional native grass plugs and wildflower seeds in Zones 2 and 3.

The buffer planting was completed with the creation of a wetland area in a poorly drained corner of the site. A backhoe removed all soil down to the clay layer, and topsoil donated by a local Mt. Holly firm was used to in-fill the wetland. After shaping, a depression was left in the center, and Rutgers personnel planted native shrubs and plugs of grasses, sedges and rushes in and around the water-filled wetland.

The Roberts Farm site. A typical agricultural site located in a pasture, the west side of the stream had little existing woody vegetation in Zone 1 (the first 15 feet (4.5 meters) from the stream) and none in Zone 2 (the next 45 feet (13.5 meters)). The east side was in an early stage of ecological succession from pasture to woodland. Site preparation in Zone 1 consisted only of removing some undesirable vegetation before planting. Zone 2 on the west side was site prepared by rototilling with a small farm tractor, while Zone 2 on the east side was not site-prepared. The existing pasture became Zone 3. Twenty different species of trees and shrubs were planted in Zones 1 and 2, totaling 750 seedlings and 200 container-grown plants. Trees and shrubs were planted in rows on the west site of the stream, and inter-planted into the existing successional vegetation on the east side. The larger, container-grown plants were interspersed with the seedlings. Selected species included several with future income potential for such things as timber, fence posts, floral materials, fruit, and nuts.

To eliminate damage from cattle and deer, a solar-powered electric fence was installed around most of the planted buffer. One hundred-and-twenty-five, 4-foot-high (1.2 meters) tree shelters or tubes were also installed on selected trees both within and outside of the animal fence for demonstration.

Almost all of the labor for installing the buffer was provided by local high school students and volunteers.

Phase 3 provided information and education on riparian forest buffers to targeted audiences primarily in the Rancocas Watershed. Community outreach has included interpretive signs, field day programs, informational meetings, distribution of articles to the media, and publication of fact sheets. Phase 3 activities were intended to increase target audience awareness, advance knowledge and understanding, promote community ownership of the Rancocas Watershed Riparian Forest Buffer System Project, and, in the long-term, to facilitate preservation, adoption, and implementation of riparian forest buffers by watershed landowners.

Phase 4 of the project’s implementation plan is to coordinate with other agencies and organizations to promote riparian forest buffer systems in New Jersey and ensure the long term success of riparian forest buffer system management throughout the state. A web page will be developed and maintained to facilitate the exchange of information on riparian buffers within the state. Thus, a network will be created where information and educational resources may be shared for the improved management of multi-species riparian forest buffer systems.

Results and Discussion

Riparian forest buffer restoration is a management alternative or opportunity for many forest landowners, homeowners and municipalities. By successfully establishing two riparian forest buffers, the project is meeting its stated objectives for demonstrating riparian forest buffer implementation. Over 100 community volunteers participated in the implementation of the buffers. The owners of both sites, the town of Mt. Holly and a private farmer, were also instrumental in project implementation and are important for the maintenance and long-term success.

Using a mix of traditional programming methods including seminars, day-long programs, and field meetings, over 12 events targeting municipal officials, farmers and landowners, natural resource management professionals, and high school students have reached over 300 key individuals and 180 students living and working within the Rancocas Watershed. Several hundred more individuals viewed a table-top display and poster developed and exhibited during Mt. Holly’s day-long ‘Race Day and Environmental Fair’ held in July, 1999. Attractive and informative but succinct signs were designed and erected on both buffer sites. Though difficult to document, literally thousands of people, from both within and outside of the watershed, annually pass the strategically placed signs. The educational value and importance of properly and prominently displayed signs for successful demonstrations cannot be overlooked.

The local newspaper media was also instrumental in reaching the general public. Four different newspapers with local and regional distributions provided coverage with articles about riparian forest buffers and the project’s objectives, including an on-site “photo opportunity” for the New Jersey Department of Environmental Protection’s Commissioner. Two informational fact sheets on riparian forest buffers, and the Mt. Holly buffer, specifically, will be available Fall, 2001, for use with a variety of audiences, including the general public.

In addition, the differences between the two sites chosen for buffer implementation provide the unique opportunity to demonstrate the flexibility and range of design options for riparian forest buffers. Both are native, multi-species, three-zone riparian forest buffers. Because of the demonstrational and educational objectives of the project, the selection criteria were practically the same, especially for visibility and accessibility. In addition to the basic and primary function of controlling nonpoint source pollution, both are intended to demonstrate the feasibility of riparian forest buffers and their multiple benefits. The Mt. Holly site, however, is in a heavily-trafficked urban park, while the Roberts Farm site is a typical agricultural site on a working farm. This required and permitted wide latitude and differences in buffer design between the two sites.

The heavy use and visibility of the Mt. Holly site offered design opportunities for aesthetics and greenway/wildlife corridor benefits that actually may equal or out-weigh the usual, primary functional benefits of a forested buffer for nonpoint source pollution control. Immediately upstream from the site the stream is forested, and some distance downstream is a wooded park followed by another forested area. Thus, the newly established riparian forest buffer is the first step in connecting these areas and providing a forested greenway for wildlife useage and travel, as well as enhancing water quality. Incorporating 50 species of native trees and shrubs into the buffer; using primarily container-grown stock; planting to mimic how these species might naturally occur in a riparian forest; including wildflower seeding in Zones 2 and 3; and incorporating a small, functioning wetland in one corner, are not necessarily requirements or features that every landowner or municipality will or should include in forest buffer restoration. However, these features enhance appearance while remaining functional, demonstrate ‘what can be done’ with buffer design, and should encourage landowners and municipal officials to more readily adopt this best management practice. The buffer design also included informative signs at both ends of the buffer as well as a footpath through Zone 2 to accommodate fishermen and encourage pedestrian usage.

A ‘typical’ agricultural site was purposely selected for the second site. The design is simpler than that of the Mt. Holly site, and reflects the primary function of a riparian forest buffer, which may be more attractive as an alternative for farmers and landowners considering buffer restoration on their own properties. The Roberts Farm site design incorporated only 20 native tree and shrub species into Zones 1 and 2, and relies on the native grass and herbaceous species already present to populate Zones 2 and 3. Seventy-five percent of the trees and shrubs were planted as bare-root seedlings and the remainder as larger, 3- to 5-foot-tall (0.9 to 1.5 meters) contain-grown stock. Planting was accomplished primarily in rows both by machine and by hand. Fifty percent of the tree and shrub species were also selected based on potential for future management and commercial products such as timber, fence posts, floral materials, nuts, fruit, and wood for ‘smoking’ when cooking. As for many areas in New Jersey, fencing was required to protect the new planting not only from the farm’s cattle, but from depredation by white-tailed deer. The buffer design effectively provides water quality and environmental benefits, wildlife habitat, and is aesthetically pleasing, while being easier to implement, requires lower ‘up-front’ investment, and has potential for future economic return from various forest products.


The goals of this project, “Implementation of Riparian Forest Buffer Systems for the Rancocas Watershed”, included the implementation of two native, multi-species, three-zone riparian forest buffers in the Rancocas Watershed to demonstrate the use and benefits of buffers; provide educational opportunities to advance awareness and understanding for school-aged youth and the general public; and to promote adoption of this best management practice by farmers, landowners, and municipal officials. One unique aspect of the project is the opportunity to demonstrate the flexibility and range of design options for riparian forest buffers using the Three-Zone Model. The heavily-trafficked, urban Mt. Holly site provides the opportunity to showcase function while incorporating recreation and aesthetic features. The typical agricultural site incorporates function and future management options while optimizing initial investment. Both utilize native species, both will offer educational opportunities well into the future, and local community involvement and volunteer efforts were essential for the success of both. Together, they demonstrate the range and flexibility for designing riparian forest buffers and offer a model for sites both within New Jersey and elsewhere.


1. Correll, D. L. 1996. Vegetated stream riparian zones: their effects on stream nutrients, sediments, and toxic substances, an annotated bibliography. Smithsonian Environmental Research Center, Edgewater, MD.

2. Ducnuigen, J., K. Willard, and R. C. Steiner. 1997. Relative nutrient requirements of plants, suitable for riparian vegetated buffer strips. Interstate Commission on the Potomac River Basin Report Number 97-4.

3. Lowrance, R., L. S. Altier, J. D. Newbold, R. R. Schnable, P. M. Groffman, J. M. Denver, D. L. Correll, J. W. Gillam, J. L. Robinson, R. B. Brinsfield, K. W. Staver, W. Lucas, and A. H. Todd. 1995. Water quality functions of riparian forest buffer systems in the Chesapeake Bay Watershed. Chesapeake Bay Program Technology Transfer Report EPA 903-R-95-004.

4. Lowrance, R., R. Leonard, and J. Sheridan. 1985. Managing riparian ecosystems to control nonpoint source pollution. Journal of Soil and Water Conservation 40:87-91.

5. New Jersey Department of Environmental Protection (NJDEP) Office of Environmental Planning. 1998. Draft 1998 identification and setting of priorities for section 303(d) water quality limited waters in New Jersey. Trenton, NJ.

6. Schultz, R. C., J. P. Colletti, T. M. Isenhart, W. W. Simpkins, C. W. Mize, and M. L. Thompson. 1995. Design and placement of a multi-species riparian buffer strip system. Agroforestry Systems 29:201-226.

7. Welsch, D. J. 1991. Riparian forest buffers: functions and design for protection and enhancement of water resources. USDA Forest Service, Northeastern Area State and Private Forestry, Forest Resources Management, Radnor, PA.

Figure 1: Map of the United States

Figure 2: Map of New Jersey and Project Area

Figure 3: The Streamside Forest Buffer: The Three-Zone Model (Welsch, 1991)

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