Riparian Buffers: Implementation and Effectiveness in VT

Created for NR 102: Water as a Natural Resource at UVM in the Rubenstein School of Environment and Natural Resources as a final research project. This class aims to educate students on human impact to freshwater ecosystems.

• Streams, rivers, lakes, wetlands, and floodplain ecosystems (VT ANR 2005)
• Extends the length of the water body, the shore, from the top of the water table to the top of the surrounding vegetation canopy, and includes all of the land directly impacted by the surface water ( VT ANR, 2005)
• Characterized by high biodiversity, varying natural conditions, and high disturbance rates.
• Extremely important habitat for a wide range of invertebrate, mammal, and plant communities

• Trees and shrubs along banks provide shade, which reduces water temperatures, filter runoff from nearby areas, which improves water quality, and provides bank stabilization to protect against erosion ( VT ANR 2005)
• Provide habitat, migration routes, and habitat connections for a diverse collection of species
• Provide scenic, recreational, and aesthetic values (NPS 2022)
  • This is especially important as many watersheds provide economic value, and keeping them in good condition for recreation and aesthetic value increases the economic output of these areas.
  • This also has important social impacts. Everyone has an inherent right to clean, accessible water, and protection and restoration of riparian buffers are one way to ensure the watershed can provide this for the community.
• According to the Lake Champlain Sea Grant, additional functions are to, "help intercept nutrients, sediment, and pesticides from nearby areas before they enter our waterways", to, "decrease the frequency and severity of flood events" and to, "store carbon as [plants] grow".

• According to the VT Agency of Natural Resources, a buffer is an area that is, "unmowed, undisturbed, and naturally vegetated" and "buffers the waterbody and riparian ecosystem from the impacts of adjacent land uses" (VT ANR, 2005)
• By restoration of riparian areas, we can recreate this natural buffer in hopes of bringing back the functions and services riparian areas provide.

• The Vermont Department of Environmental Conservation lists the benefits as follows:

• Protect human land use and infrastructure against damages of flooding.
  • Use of, "vegetated buffers and recognition of the relationship of flood plains and channel planform to stream stability to avoid conflicts with human investments" is a way to provide protection and mitigation of hazards and destruction caused by flooding and consequent erosion ( VT DEC).
  • Ideally, infrastructure and development so close to riparian areas would be avoided, but in more cases than not, this happens quite frequently. Riparian buffers are a method used to mitigate impacts caused by this development.
  • Below is a map of Vermont's Subwatershed boundaries and their percent impervious surface. Maps like these can be used to identify which sub watersheds might be most at risk and could benefit most from the installation and restoration of riparian areas.

Vermont Subwatershed Percent Impervious Surface

• Increase surrounding land productivity for agricultural uses.
  • For example, lakeshores can be made more stable by planting, "natural mixed vegetation (trees, shrubs, and ground cover) that can resist the forces of spring ice push and wave action" (VT DEC).
  • These plants and their roots provide the stability stream beds rely on to be resistant to erosion and maintain proper function and protection from further widening and erosion. This allows more lateral land to be used for agricultural production, as many areas surrounding riparian areas tend to be the most productive.
  • Proper stream bed function is dependent on the effective distribution and dispersion of water following a storm because of intact flood plains and the presence of riffles, pools, and runs within the stream itself (VT DEC).

• The most common problem regarding water quality in Vermont is pollution. Vegetated buffers around water sources not only slow runoff, but also provide filtration of this water.
  • The vegetation filters out, "sediments, nutrients, pathogens, and toxins originating from upland sources" (VT DEC).
  • The vegetation then breaks down these pollutants and incorporates them into the soil and/or plants before reaching the water.
  • Vegetated buffers prevent these pollutants from making their way into the water and further reducing water quality.
  • By protecting water quality, this reduces costs time of having to treat drinking water more in order to filter these pollutants and reduces the chances of negative health implications to humans and wildlife (VT DEC).
• Streams shaded by tree and shrub vegetation along the bank provide cooler temperatures and hold more oxygen, which allows the stream to have a higher, "capacity to assimilate organic wastes from sewage plant discharges and nonpoint sources of pollution" (VT DEC).
  • This is especially important because many of Vermont's municipal wastewater treatment plants discharge wastewater into local surface water.

• Take a look around you! A lot of the time, surrounding tree or shrub species can provide a good indicator of what will be successful and most natural in that area.
• Take time to identify the natural community in your restoration area. This will indicate important factors such as the soil type, condition, and flood regime. It is essential to select species that will be successful given the ecological profile. You should focus on planting native species, rather than introduced or naturalized species.
  • After you've gathered this information, it's time to get planting!
• Click the link below to view The Vermont Department of Environmental Conservation recommendations:

• The New York State Department of Environmental Conservation recommends the three zone technique for riparian buffers
  • Zone 1: This is the area closest to the stream, and this should be at least 15 feet wide. This is where native, water tolerant trees and shrubs should be planted to provide leaf litter and bank stabilization.
  • Zone 2: This zone should be between 20-60 ft wide and contain smaller, shade tolerant shrubs and trees. This is where water gets filtered, so faster growing plants should be planted here.
  • Zone 3: This is the area farthest away from the wetland. This could be a field or pasture edge. Plants suited for this area are grasses, wildflowers, and other herbaceous plants. This zone should extend from 15-60 feet.

• NYS DEC recommends a total of at least 100 feet of all three zones. The wider the buffer is, the more protection the stream or wetland gets from pollutants and the more habitat is provided for local wildlife. Additionally, it is recommended to increase the diversity within each zone. The more diverse the vegetation is, the more resilient the ecosystem can be (NYSDEC).

A study done by The Lake Champlain Basin Agricultural Watersheds National Monitoring Program (NMP) from 1994-2000 monitored, "stream discharge recording, flow-proportional sampling for nutrients and suspended solids, intensive grab sampling for indicator bacteria, and tracking of land use and agricultural management in the watersheds" (Meals 2004) in watersheds within the Missisquoi River Basin. In 1997, the selected watersheds underwent treatment consisting of riparian restoring and fencing, using alternative water supplies, streambank bioengineering (riparian fencing, alternative water supplies, protected stream crossings, and streambank bioengineering).

Here are the results:

• 20-50% reductions in suspended solids concentrations
• 40-60% reductions in bacteria counts

Another study published in 2010 studied the effectiveness of treed habitats (whether this is riparian buffers, hedgerows, or woodlots) in the Lamoille watershed, one of Vermont's most agriculturally focused areas. The study states that, " the quality of the water in the lake has declined partly as a result of agricultural activities in the watershed, including nutrient runoff (especially phosphorus) to rivers that drain into the lake" and that stakeholders were concerned about this agricultural runoff polluting Lake Champlain (Lovell et al. 2010).

Results showed that a lot of farm study sites were located in close proximity to hydrological sites within the watershed and that, " agriculture comprised 28%, 34%, and 50% of the land cover within 1000, 500, and 100 m buffer zones of the rivers" (Lovell et al. 2010). This shows the need for these treed areas - in this case riparian buffers- in the state of Vermont, particularly in agriculturally robust areas.

To the right is a figure published from this study depicting the farm study sites and their proximity to hydrologic features within the Lamoille watershed.

A study on water quality improvements on a watershed in Connecticut and published in the Journal of Environmental Quality, revealed that when compared to a control area showed decreases in, " overland flow concentrations of TKN by 70%, NO ₃ -N by 83%, TP by 73%, and total suspended solids (TSS) by 92% as compared with the control" (where Kjeldahl nitrogen is (TKN) and total phosphorus is (TP) and Nitrate N is (NO ₃ -N)) (Clausen et al. 2000). Additionally, the study revealed that restoration of the riparian area decreased nitrate concentration in the ground water by 35% when compared to the control (Clausen et al. 2000).

While not in New England, another study on a Coastal Plain in Georgia on a restored forested riparian wetland next to a heavily fertilized pasture shows similar results. The study states that, "The forest buffer significantly reduced incoming dissolved nitrate-N, dissolved ammonium, total ammonium, and total orthophosphate masses in surface runoff by 97, 74, 68, and 78 respectively within the 10.0 m riparian buffer" (Vellidis et al. 2003).

When this study compared Nitrate, total N, Dissolved Reactive Phosphorus (DRP), and total P from the edge of the restored riparian area to the streamflow output the results showed, "edge of field concentrations significantly higher than the streamflow outputs" showing that as water moves through a buffer, filtration occurs and water quality is higher once doing this (Vellidis et al. 2003).

Though this research is well outside of the New England area, these results can still be applied to New England as well, as much of the land use is agricultural as well.

Clausen, J.C., Guillard, K., Sigmund, C.M. and Dors, K.M. (2000), Water Quality Changes from Riparian Buffer Restoration in Connecticut. Journal of Environmental Quality, 29: 1751-1761.  https://doi.org/10.2134/jeq2000.00472425002900060004x 

Kirn , R. (2016). Planting Guidance for the Revegetation of Riparian Areas in Vermont. Vermont Department of Environmental Conservation.

Lovell, S.T., Mendez, V.E., Erickson, D.L. et al. Extent, pattern, and multifunctionality of treed habitats on farms in Vermont, USA. Agroforest Syst 80, 153–171 (2010). https://doi.org/10.1007/s10457-010-9328-5

Meals, D.W. (2004). Water Quality Improvements Following Riparian Restoration in Two Vermont Agricultural Watersheds. In: Manley, T.O., Manley, P.L., Mihuc, T.B. (eds) Lake Champlain: Partnerships and Research in the New Millennium. Springer, Boston, MA. https://doi.org/10.1007/978-1-4757-4080-6_6

Natural Resources Conservation Service vermont NRCS - USDA. (2009). Retrieved December 7, 2022, from https://efotg.sc.egov.usda.gov/api/CPSFile/22122/391_VT_PS_Riparian_Forest_Buffer_2009

Riparian Buffers and Corridors. Vermont Agency of Natural Resources . (2005). Retrieved December 7, 2022, from https://anr.vermont.gov/sites/anr/files/co/planning/documents/guidance/Riparian%20Buffers%20and%20Corridors%20-%20Technical%20Papers.pdf

Riparian buffers. Riparian Buffers - NYS Dept. of Environmental Conservation. (n.d.). Retrieved December 7, 2022, from https://www.dec.ny.gov/chemical/106345.html

U.S. Department of the Interior. (n.d.). Riparian zones-it's all about the water (U.S. National Park Service). National Parks Service. Retrieved December 7, 2022, from https://www.nps.gov/articles/000/nrca_glca_2021_riparian.htm

Values of riparian buffers - Vermont. Vermont Department of Environmental Conservation. (n.d.). Retrieved December 7, 2022, from https://dec.vermont.gov/sites/dec/files/wsm/rivers/docs/rv_riparianvalues.pdf

Vellidis, G., Lowrance, R., Gay, P. and Hubbard, R.K. (2003), Nutrient Transport in a Restored Riparian Wetland. J. Environ. Qual., 32: 711-726.  https://doi.org/10.2134/jeq2003.7110 

Why riparian forest buffers? Why riparian forest buffers? | Lake Champlain Sea Grant. (n.d.). Retrieved December 7, 2022, from https://www.uvm.edu/seagrant/watershed-forestry-partnership/why-riparian-forest-buffers

• all image credit given in the (i) icon on top left