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Missisquoi Bay Basin Study
Identification of Critical Source Areas of Phosphorus Pollution
Missisquoi Bay has one of the highest phosphorus concentrations of any part of Lake Champlain. Phosphorus contributes significantly to blooms of cyanobacteria (blue-green algae) during the summer months. As local residents and many visitors know, these blooms are often so dense that recreational use is not possible for many weeks at a time in some parts of the Lake.
In a 2005 report, the International Joint Commission (IJC) identified the water quality status in Missisquoi Bay as an urgent matter of binational concern and recommended that the governments of Canada and the United States take the necessary steps, individually and jointly, to assist in reducing phosphorus levels. The 2005 study reported that phosphorus loads (the amount of phosphorus introduced into the bay from external sources) and ambient levels greatly exceed the target levels established by the provincial and state governments.
The Governments of Canada and the United States, in a formal request (known as a Reference) dated August 1, 2008, asked the IJC to coordinate initiatives in both countries to reduce phosphorus loading to Missisquoi Bay on Lake Champlain. The IJC established the International Missisquoi Bay Study Board to help carry out this responsibility. As one of the first actions under the Reference, the IJC conducted hearings with the Study Board on each side of the international border in the Missisquoi Basin on December 15 and 16, 2008. Members of the public shared their perspectives, concerns and knowledge of local circumstances pertinent to this work. The IJC also convened public outreach sessions to provide an overview of progress on October 12 and 13, 2010, in Swanton, VT and St. Armand, QC.
The Reference recognized advances made by the Province of Québec in identifying critical sources of phosphorus within its areas of jurisdiction, and specifically asked the IJC to coordinate a number of corresponding tasks on the U.S.-side of the border in partnership with the Lake Champlain Basin Program. These tasks included:
- identifying critical source areas in the watershed that contribute disproportionately to phosphorus levels in the Missisquoi Bay;
- acquiring and compiling necessary data and imagery; and
- monitoring water quality in small tributaries in the Missisquoi watershed over a two-year period.
The outcomes of this work were compiled and analyzed with other data to provide an integrated picture of the watershed on both sides of the border. Two appropriations from the U.S. Congress totaling $800,000 supported this work. The IJC’s final report on the work carried out under the Reference was completed in December 2011 and is available on the IJC’s Missisquoi Bay Critical Source Area Study web page.
More information is available online at the site of the International Missisquoi Bay Study Board, including the letters of reference from the governments of Canada and the United States to the IJC, the directive from the IJC to its Study Board, and transcripts from the public hearings.
As part of the request from the IJC, the LCBP convened four public workshops and meetings to help guide the critical source area identification project. The objectives of the workshops included:
- exploring optimal spatial scale and extent, modeling methods, and parameters for the definition, identification and delineation of critical source areas
- discussing available existing data and gaps in data that would need to be filled
- structuring and designing the short-term monitoring program and discussing long term monitoring needs
- discussing optimal means to compile and analyze information to provide a transboundary understanding of pollutant loads
- examining the role of spring runoff and flooding on nutrient loads
- evaluating the recent information compiled by the USDA-NRCS Missisquoi Areawide Plan
The LCBP held the following workshops (please see workshop summaries for more details):
- Tributary Monitoring in the Missisquoi Bay Basin – December 15, 2008 <summary>
- Defining Critical Source Areas and Management Needs – January 22, 2009 <summary>
- Approaches to Identifying Critical Source Areas in the Missisquoi Bay Basin – March 12-13, 2009 <summary>
- Data Availability and Data Needs – April 28, 2009 <summary>
The LCBP also convened a workshop to discuss transboundary hydrographic data harmonization for the Lake Champlain Basin. Workshop goals were to:
- Identify, evaluate and verify the condition of hydrographic data in the Missisquoi Bay
watershed in the context of the greater Champlain Drainage system.
- Garner a better understanding of the hydrographic geospatial datasets used by
natural resource agencies in the Champlain Basin.
- Identify appropriate base data to use for potential harmonization.
- Identify future applications utilizing harmonized data.
- Plan a Data Harmonization Workshop for the Champlain Basin.
For more information:
- Lake Champlain Basin Hydrographic Data Assessment Workshop Summary – 16/17 March 2010 <English | Français>
- Hydrographic Workshop Agenda: Executive Summary <English | Français>
Identifying Critical Source Areas of Phosphorus Pollution through Modeling
The LCBP released an RFP in January 2010 with funds secured through the IJC ) for technical services to identify predominant types of critical source areas of phosphorus loads in the Vermont sector of the Missisquoi basin, as well as their physical locations. The goal of this work was to provide resource agencies with a better understanding of the types and locations of areas they should target for better land stewardship in order to significantly reduce the phosphorus loads to Lake Champlain’s Missisquoi Bay. Development of this RFP was informed by a workgroup of local stakeholders as well as a technical peer review of proposed project objectives and outcomes. For a summary of the review:
LCBP Reports and Executive Summaries
The LCBP was tasked with defining parameters, methodologies, data requirements and quality assurance measures needed for the identification and delineation of critical source areas; analyzing data gaps; acquiring available data; and establishing a peer review process for the modeling approach. For more information on these tasks:
- Task 1 Summary – 27 October 2009: Executive Summary English | Français>
- LCBP Final Modeling Report – 05 January 2012:<English | Français>
The LCBP was also tasked to monitor water quality in small tributaries in the basin over a two-year period. A Quality Assurance Project Plan was developed to support this monitoring effort. For more information on the Short-term Monitoring Program:
- Quality Assurance Project Plan: Executive Summary <English | Français>
- First Interim Report – 22 December 2009: Executive Summary <English | Français>
- Second Interim Report – 23 November 2010: Executive Summary <English | Français>
- Final Report – August 2011: Executive Summary < English | Français>
Stone Environmental, Inc. (Stone) was selected as the project contractor for the phosphorus critical source area identification modeling, and began work in early June 2010 after workplan approval and development of a quality assurance plan for the project. The Soil and Water Assessment Tool – Variable Source Area Model (SWAT-VSA) [http://swat.tamu.edu/] was adapted for this project. For more information on this work:
- Workplan – 13 May 2010: Executive Summary <English | Français>
- Quality Assurance Project Plan
- First Interim Report – 30 November 2010: Executive Summary <English | Français>
- Second Interim Report – 22 March 2011: Executive Summary <English | Français>
- Stone Environmental Final Report for the LCBP (50MB) – 15 December 2011;
Executive Summary (4MB)
- LCBP Final Report for the International Joint Commission – December 2011
Relevant Geospatial Datasets and Local Research Projects
The Missisquoi Areawide Plan [1/08]
Bank Stability and Toe Erosion Modeling (BSTEM) of the Missisquoi Watershed [objectives: 8/09]