Lake Champlain Phosphorus TMDL: A Commitment to Clean Water

Excess phosphorus from a variety of sources has impaired the water quality of Lake Champlain. In 2002, Vermont prepared a plan to reduce phosphorus loadings by developing a Total Maximum Daily Load (TMDL). A TMDL places a cap on the maximum amount of phosphorus that is allowed to enter the Lake and still meet Vermont's water quality standards. EPA disapproved the Vermont 2002 Lake Champlain Phosphorus TMDL in 2011.

On June 17, 2016, EPA established new phosphorus TMDLs for the twelve Vermont segments of Lake Champlain. The TMDLs were developed in collaboration with the Vermont Agency of Natural Resources, Department of Environmental Conservation and the Vermont Agency of Agriculture, Food and Markets.

The phosphorus TMDLs for the Vermont Segments of Lake Champlain and supporting documents can be accessed at the links below. The supporting documents include appendices, a response to comments received on the proposed TMDLs, and a summary of changes from the proposed to final TMDLs.

Since TMDL issuance, EPA has been tracking the State of Vermont's progress toward TMDL implementation goals. EPA report cards and related correspondence between EPA and the State are provided below.

TMDL Implementation Progress Reports, EPA Report Cards, and Related Correspondence between EPA and the State of Vermont

The 2016 Lake Champlain Phosphorus TMDL document includes an Accountability Framework with milestones for the State of Vermont to meet by certain dates. The items below include Vermont reports on meeting these milestones, EPA report cards evaluating this progress, and related correspondence between EPA and the State of Vermont.

• EPA April 6, 2023 Lake Champlain TMDL Implementation Interim Report Card for Basin 3: Otter Creek, Little Otter Creek, and Lewis Creek; and Final Report Card for Basins 2 and 4: South Lake Champlain (pdf) (138 KB)
• EPA April 22, 2022 Lake Champlain TMDL Implementation Interim Report Card for Winooski and Final Report Cards for Missisquoi and Lamoille Tactical Basin Plans (pdf) (136 KB)
• EPA September 3, 2020 Final Report Card on the State of Vermont's TMDL Phase 1 Implementation Progress (pdf) (275 KB)
• EPA June 25, 2020, Letter to VT Department of Environmental Conservation on Lake Champlain TMDL Phase 1 Milestones (pdf) (241 KB)
• EPA April 14, 2020 Interim Report Card on Lamoille and Missisquoi Tactical Basin Plan Implementation (pdf) (94 KB)
• VT Agency of Natural Resources January 15 Letter to EPA Transmitting the 2019 Clean Water Initiative Performance Report (pdf) (138 KB)
• State of Vermont 2019 Clean Water Initiative Performance Report (pdf) (8.8 MB)
• EPA July 11, 2019 Letter to VT Agency of Natural Resources on Establishment of Long-Term Funding Mechanism (pdf) (204 KB)
• EPA April 22, 2019 Letter to VT Agency of Natural Resources on State TMDL Reporting Process, Timing and Content (pdf) (315 KB)
• VT Agency of Natural Resources April 1, 2019 Letter to EPA on TMDL Reporting Process, Timing and Content (pdf) (502 KB)
• EPA April 2018 Report Card on State of Vermont's TMDL Implementation Progress (pdf) (2.2 MB)
• State of Vermont March 2018 TMDL Implementation Progress Report to EPA (pdf) (4.5 MB)
• EPA February 2017 Interim Report Card on State of Vermont's TMDL implementation Progress (pdf) (592 KB)

Total Maximum Daily Load Document and Appendices

• Establishment Letter (pdf) (242 KB)
  Transmits the TMDLs to the Vermont Agency of Natural Resources
• Phosphorus TMDLS for Vermont Segments of Lake Champlain (pdf) (2.1 MB)
  Provides allocations of phosphorus loads to Lake Champlain to meet water quality criteria
  Note: Due to a document production problem, any downloads of this document prior to June 20, 2016 contained some typographical and numerical errors on p. 38.
• Appendix A (pdf) (1.5 MB)
  Describes basis for allocation for future growth
• Appendix B (pdf) (384 KB)
  Describes how implementation measures were simulated to determine that allocations can be achieved
• Response to Comments (pdf) (2.4 MB)
  Presents public comments and EPA's responses, organized by subject
• Changes from Proposed to Final TMDLs (pdf) (90 KB)
  Presents summary of important changes made to the TMDLs since the August 15, 2015 proposal
• Memorandum of Understanding (pdf) (325 KB)
• Assessment and Total Maximum Daily Load Tracking and Implementation System (ATTAINS) Data Sheet (pdf) (48 KB)

August 2015 Proposed Total Maximum Daily Load Document and Appendices

• Proposed Phosphorus TMDLS for Vermont Segments of Lake Champlain (August 2015) (pdf) (2.1 MB)
  Provides allocations of phosphorus loads to Lake Champlain to meet water quality criteria
• Proposed Appendix A (August 2015) (pdf) (815 KB)
  Describes basis for allocation for future growth
• Proposed Appendix B (August 2015) (pdf) (375 KB)
  Describes how implementation measures were simulated to determine that allocations can be achieved

Vermont Lake Champlain Phosphorus TMDL Phase 1 Implementation Plan (Draft, August 2015)

• Vermont Lake Champlain Phosphorus TMDL Phase 1 Implementation Plan (pdf) (2.2 MB)
  Describes implementation measures Vermont will take to achieve the allocations in the TMDLs.
  • Appendices (pdf) (9.1 MB)

Public Meetings, Press Releases and Presentations

• August 2015 Public Meeting Presentation (pdf) (973 KB)

2002-2011 TMDL documents

• 2002 Lake Champlain Phosphorus TMDL Approval Documents (pdf) (108 KB)
• 2002 Lake Champlain Phosphorus TMDL (pdf) (1 MB)
• 2011 TMDL Disapproval Letter and Determination (pdf) (1.2 MB)

Technical Reports

• In-lake Modeling Recommendation Report (pdf) (983 KB)
  This report describes the recommended modeling approach for the in-lake modeling component of the Lake Champlain TMDL project. The report was prepared by Tetra Tech, with input from the Lake Champlain modeling workgroup. (TetraTech, 2012b)
• Lake Champlain BATHTUB Model Calibration Report (pdf) (1.5 MB)
  The BATHTUB model was used to generate updated loading capacities for each lake segment that would result in the achievement of water quality standards. This model establishes the relationship between phosphorus inputs to the lake and the effects these loads have on phosphorus concentrations in each lake segment. This report describes how the Lake Champlain BATHTUB model was updated and calibrated using long-term lake and tributary monitoring data. (TetraTech, 2015a)
  • BATHTUB Model Calibration Report Appendices (pdf) (12.5 MB)
• Lake Champlain TMDL Modeling Quality Assurance Project Plan (pdf) (1.9 MB)
• BATHTUB Model Quality Assurance Review (pdf) (241 KB)
  This technical memorandum describes the results of an internal (Tetra Tech) quality assurance review of the Lake Champlain BATHTUB modeling following model calibration. (TetraTech, 2014a)
• Watershed Modeling Recommendation Report (pdf) (903 KB)
  This report describes the recommended modeling approach for watershed modeling component of the Lake Champlain TMDL project. The report was prepared by Tetra Tech, with input from the Lake Champlain watershed analysis workgroup. (TetraTech, 2012a)
• SWAT Model Configuration, Calibration and Validation (pdf) (4.3 MB)
  The Soil and Water Assessment Tool (SWAT) model was used to develop phosphorus loading estimates for sources in the Lake Champlain Basin. This document describes the model setup and parameterization, and presents calibration results. The model accounts for loads from Vermont, New York and Quebec, but includes more detail on the Vermont portion of the watershed given that EPA is responsible for developing Vermont phosphorus load and wasteload allocations. The detailed calibration results are included in appendices C - K, organized by watershed or groups of watersheds. (TetraTech, 2015b)
  • SWAT Calibration Report Appendices (pdf) (24 MB)
• SWAT Model Quality Assurance (pdf) (392 KB)
  This technical memorandum describes the results of an internal (Tetra Tech) quality assurance review of the SWAT modeling following model calibration. (TetraTech, 2014b)
• Lake Champlain BMP Scenario Tool Report (pdf) (1.7 MB)
  Using the Lake Champlain Basin SWAT watershed model results and BMP efficiency rates, Tetra Tech developed a spreadsheet-based tool that allows one to evaluate the amount of phosphorus reduction expected from different combinations of BMPs in Vermont Lake Champlain tributary watersheds. This report describes the design, function, and data requirements for the scenario tool. (TetraTech, 2015c)
• Projected Changes in Phosphorus Loads due to Climate Change (pdf) (1.4 MB)
  This report describes how the Lake Champlain SWAT model was used to project changes in flow, sediment and phosphorus inputs to Lake Champlain associated with climate change. (TetraTech, 2015d)
• Missisquoi Bay Phosphorus Model Addendum (pdf) (450 KB)
  This technical memorandum provides results of an extended load reduction simulation. (LimnoTech, 2015) The memorandum serves as an addendum to the main Missisquoi Bay Phosphorus Mass Balance Model report prepared for the Lake Champlain Basin Program by LimnoTech in 2012 (pdf) (2 MB) (LimnoTech, 2012)
• Technical Review of Lake Champlain TMDL Modeling Tools (pdf) (615 KB)
  This memo provides an external review of the models used in developing the TMDL. (WaterVision, 2015)
• Wastewater Treatment Facilities Feasibility (WWTF) Study (pdf) (4.9 MB)
  EPA contracted with Tetra Tech to assess what type of upgrades would be needed and what the main costs would be if WWTFs were to further reduce phosphorus inputs to Lake Champlain. Some information on the New York facilities is also included in this study for completeness purposes.