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Impaired Waters and TMDLs

Lake Champlain Phosphorus TMDL: A Commitment to Clean Water

Scenic view of Lake Champlain with a lighthouse in the foregroundExcess 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.

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Total Maximum Daily Load Document and Appendices

August 2015 Proposed Total Maximum Daily Load Document and Appendices

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

Public Meetings, Press Releases and Presentations

2002-2011 TMDL documents

Technical Reports

  • In-lake Modeling Recommendation Report
    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
    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)
  • Lake Champlain TMDL Modeling Quality Assurance Project Plan
  • BATHTUB Model Quality Assurance Review
    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
    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
    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 Model Quality Assurance
    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
    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
    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
    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) (89 pp, 2 MB) Exit (LimnoTech, 2012)
  • Technical Review of Lake Champlain TMDL Modeling Tools
    This memo provides an external review of the models used in developing the TMDL. (WaterVision, 2015)
  • Wastewater Treatment Facilities Feasibility (WWTF) Study
    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.