Lake Champlain, the nation's sixth largest freshwater lake, is undergoing cultural eutrophication due to excessive phosphorus loads from its 20,800 km2 drainage basin, found in portions of Vermont, New York, and Quebec. 71% of the average annual phosphorus (P) load of 647 metric tonnes comes from nonpoint sources, and two-thirds of this is estimated to come from agricultural land in the basin. The current management strategy for Lake Champlain calls for reductions of P loading from both point and nonpoint sources. Much of this reduction will need to come from agricultural land.

Efforts to reduce agricultural nonpoint source pollution in Vermont over the past several decades have focused on improving animal waste management in the state's predominantly dairy agriculture. Construction of manure storage structures, barnyard runoff management, and adoption of waste utilization plans to avoid winter spreading of manure have been widely encouraged under a variety of federal and state cost-share and technical assistance programs. However, dairy cows traditionally spend half of the year away from the barn on pasture, and livestock grazing impacts on water quality have not been addressed in previous nonpoint source reduction efforts. Free access to streams and streambanks by livestock is commonplace in Vermont. Direct deposition of waste into streams, destruction of riparian vegetation, and trampling of streambanks and streambeds are all problems associated with livestock grazing. Such activities may represent important sources of sediment, nutrients, and bacteria to surface waters in Vermont. It is essential to test simple, practical, and cost-effective methods to address these issues and to provide quantitative evaluations of their effectiveness at improving water quality.

Our goal is to evaluate the effectiveness of grazing management, livestock exclusion, and streambank protection as tools for control of agricultural nonpoint source pollutants in the Lake Champlain Basin.

Principal Objectives:

• Implement practical, low-technology practices to protect streams, streambanks, and riparian zones from livestock grazing;
• Document changes in concentrations and loads of nonpoint pollutants - total Phosphorus (TP), total Kjeldahl Nitrogen (TKN), total suspended solids (TSS), bacteria - in response to treatment;
• Evaluate response of stream biota to land treatment;
• Track agricultural management activities;
• Assess operation, maintenance, and cost issues associated with treatments.

We employ a three-way paired watershed design to account for hydrologic variation over the six-year project lifetime, including:

• Two treatment watersheds, each with different levels of treatment;
• One control watershed, with no treatment;
• Three years of calibration monitoring (1994 - 1997);
• One season of treatment implementation (summer, 1997);
• Three more years of post-treatment monitoring (1997 - 2000).

A) The study watersheds are located in the Missisquoi River basin, which contributes the greatest proportional share of phosphorus among all tributary rivers in the Lake Champlain Basin.

B) Year-round monitoring stations are located at watershed outlets. A schematic of a monitoring stations' design is also available.

• Continuous streamflow monitoring

• Automated, flow-proportional water sampling for:
  • Total Phosphorus (TP)
  • Total Kjeldahl Nitrogen (TKN)
  • Total Suspended Solids (TSS)

• Twice weekly grab samples for:
  • E. coli
  • Fecal coliform
  • Fecal streptococci
  • Temperature
  • Conductivity
  • Dissolved Oxygen
• Annual macroinvertebrate sampling by kick net and fish sampling by electroshocking near watershed outlets and local reference site

• Three recording precipitation gages

C) Land use and agricultural management monitoring is accomplished by reviewing landowner records and conducting interviews.

D) Treatments are designed and installed by cooperating agencies, landowners, project staff, citizens' groups, and volunteers.

Practices used:

Riparian zone fencing;

• Temporary
• Permanent
• Variable width

Water systems;

• Pipeline and tank
• Pasture pumps
• Water gap

Stream crossings;

• Bridge
• Culverts
• Armored grade crossings

Streambank bioengineering;

• Brushrolls
• Tree revetments
• Willow plantings.

Summary: Monitoring was completed in November, 2000. Final results from three years of post-treatment monitoring confirm that significant reductions in TP, TKN and TSS concentrations and loads and in bacteria counts occurred in response to livestock exclusion and riparian restoration Significant improvements in macroinvertebrate communities were documented in treatment streams, but fish communities did not change over the life of the project. Riparian zone protection/restoration is a cost-effective tool for reducing nonpoint source pollutant concentrations and loads from livestock grazing lands in the Lake Champlain Basin.

Click here (pdf, 1.1 MB) to view the Final Report: May 1994 - November 2000: Lake Champlain Basin Agricultural Watersheds 319 NMP Project.

For additional information on the Lake Champlain Basin Agricultural Watersheds Section 319 National Monitoring Project, contact Vermont nonpoint source coordinator Rick Hopkins.

Updated: August 2001