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Region 1: EPA New England

Lake Champlain Phosphorous TMDL: A Commitment to Clean Water

Lake Champlain

Excess phosphorous from a variety of sources has impaired the water quality of Lake Champlain. In 2002, Vermont prepared a plan to reduce phosphorous loadings by developing a Total Maximum Daily Load (TMDL). A TMDL places a cap on the maximum amount of phosphorous that is allowed to enter the Lake and still meet Vermont's water quality standards. EPA disapproved the Vermont 2002 Lake Champlain Phosphorus TMDL on January 24, 2011 (see Disapproval Letter (PDF) (20 pp, 524 K)), and EPA is now obligated to prepare a new TMDL. EPA is collaborating with VTDEC and other Vermont agencies on this endeavor.

A series of six public meetings are being held in December, 2013 to share information on the amount of phosphorus reduction needed to restore the water quality of Lake Champlain, and obtain public input on a range of policy options (PDF) (30 pp, 393 K) being considered to achieve this reduction. A schedule for the preparation and final issuance of the TMDL is below. While the draft TMDL itself is not scheduled for completion until the spring of 2014, links to a number of supporting documents, such as reports describing the modeling work being used in the TMDL process, are provided here. Most of these documents were prepared by Tetra Tech, under contract with EPA.

You will need Adobe Reader to view some of the files on this page. See EPA's PDF page to learn more about PDF, and for a link to the free Acrobat Reader.

Public Meetings, Press Releases and Presentations

VT Department of Environmental Conservation: Vermont Lake Champlain Phosphorus TMDL Phase I Implementation Plan (May 29, 2014)

EPA Comments on draft Phase I Plan: Lake Champlain Total Maximum Daily Load (VT DEC March 31, 2014)

EPA Comments on draft "State of Vermont Proposal for a Clean Lake Champlain"

TMDL Schedule

2002 TMDL Documents

Technical Reports

  • In-lake Modeling Recommendation Report (PDF) (38 pp, 983 K)
    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.
  • In-lake BATHTUB Modeling Report (PDF) (21 pp, 609 K)
    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 phosphorous 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.
  • Watershed Modeling Recommendation Report (PDF) (18 pp, 900 K)
    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.
  • SWAT Model Configuration, Calibration and Validation (PDF) (42 pp, 5.2 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.
  • Draft BMP Scenario Tool Report (PDF) (60 pp, 2.3 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. This is a draft report – we are continuing to refine the scenario tool.
  • Description of the "Expanded BMP Scenario" (PDF) (2 pp, 98 K)
    This is a short summary of the BMPs included in one example scenario that EPA has input into the scenario tool for Vermont tributary watersheds in the Lake Champlain basin.
  • Projected Changes in Phosphorus Loads due to Climate Change (PDF) (48 pp, 2 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.
  • Wastewater Treatment Facilities Feasibility (WWTF) Study (PDF) (198 pp, 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. Note that EPA has not yet made any decisions regarding what level of phosphorus reduction may be required in the TMDL for the Vermont WWTFs. Some information on the New York facilities is also included in this study for completeness purposes.

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