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Modeling Workgroup

Scope and Purpose

The Chesapeake Bay Program integrated models include simulations of the airshed, watershed, estuary, living resources, and climate change. These integrated models assess effects of current and proposed watershed management on changes in nutrient and sediment loads delivered to the Bay, and the effect those changing loads have on water quality and living resources. The CBP Models assist CBP decision-makers in estimating the collective actions needed to achieve State and Federal water quality standards necessary to restore the Bay.


  • Develop cutting-edge and technically defensible modeling tools as directed by CBP decision-makers.
  • Develop airshed, watershed, estuary, living resource, and climate change scenarios as directed by CBP decision makers.
  • Estimate the aggregate effect of management practices from each source sector due to changes in land use, atmospheric deposition, fertilizer application, animal populations, manures, and management actions.
  • Track and quantify nutrient and sediment loads as implementation progresses in the Watershed Implementation Plans (WIPs) towards the 2025 goal to have all management measures in place to achieve the Chesapeake living resource based water quality standards.
  • Develop scenarios to assess management actions needed to fully achieve Bay water quality standards that are cost effective, equitable through a dialog with CBP decision-makers.

Overall CBP Model Framework

The CBP model framework is designed to address questions of how Chesapeake Bay water quality will respond to changes in watershed and airshed management actions.  In the first step of model scenario development, scenario management actions are interpreted by several models, including the Land Use Change Model, the Airshed Model, and Scenario Builder to produce input to the Watershed Model, as shown in the figure below.  The CBP Land Use Change Model, predicts changes in land use, sewerage, and septic systems given changes in land use policy. The Airshed Model, a national application of Community Multiscale Air Quality Model (CMAQ), predicts changes in deposition of inorganic nitrogen due to changes in emissions. The Scenario Builder software combines the output of these models with other data sources, such as the US Census of Agriculture, to generate inputs to the Watershed Model.  The Phase 5.3 Watershed Model predicts the loads of nitrogen, phosphorus, and sediment that result from the given inputs.The estuarine Water Quality and Sediment Transport Model (WQSTM) (also known as the Chesapeake Bay Model) predicts changes in Bay water quality due to the changes in input loads provided by the Watershed Model. As a final step, a water quality standard analysis system examines model estimates of DO, chlorophyll, and water clarity to assess in time and space the attainment of the Bay living resource-based water quality standards.


Additional information can be found at:

  • Lee Currey (Co-Chair), Maryland Department of the Environment
  • Dave Montali (Co-Chair), West Virginia Department of Environmental Protection
  • Lewis Linker (Coordinator), U.S. Environmental Protection Agency
  • Kyle Hinson (Staff), Chesapeake Research Consortium

  • Mark Bennett, U.S. Geological Survey (USGS)
  • Steve Bieber, Metropolitan Washington Council of Governments
  • Bill Brown, University of Delaware Cooperative Extension
  • Arthur Butt, Virginia Department of Environmental Quality
  • Monir Chowdhury, District of Columbia Department of Energy & Environment (DOEE)
  • Robin Dennis, U.S. Environmental Protection Agency, National Oceanic and Atmospheric Administration (NOAA)
  • Steve Gladding, New York State Department of Environmental Conservation
  • Bill Keeling, Virginia Department of Environmental Quality
  • Ross Mandel, Interstate Commission on the Potomac River Basin (ICPRB)
  • George Onyullo, District of Columbia Department of Energy & Environment (DOEE)
  • Gary Shenk, U.S. Environmental Protection Agency
  • Helen Stewart, Maryland Department of Natural Resources
  • Peter Tango, U.S. Geological Survey (USGS)
  • Ted Tesler, Pennsylvania Department of Environmental Protection
  • Harry Wang, Virginia Institute of Marine Science (VIMS)

Past Meetings & Events

  • November 3, 2015 to November 4, 2015 - November 2015 Modeling WG Quarterly Meeting
  • July 21, 2015 to July 22, 2015 - July 2015 Modeling WG Quarterly Meeting
  • April 22, 2015 to April 23, 2015 - April 2015 Modeling Quarterly Review
  • February 19, 2015 - Shallow Water Modeling Call
  • January 28, 2015 to January 29, 2015 - January 2015 Modeling Quarterly Review (Part 2)
  • January 14, 2015 to January 15, 2015 - January 2015 Modeling Quarterly Review (Part 1)
  • April 9, 2013 to April 10, 2013 - April 2013 Modeling Quarterly Review
  • January 8, 2013 to January 9, 2013 - January 2013 Modeling Quarterly Review
  • October 2, 2012 to October 3, 2012 - October Modeling Quarterly Review
  • January 11, 2012 - Modeling Team Quarterly Review

  • FINAL Water Quality Model Calibration Run January, 2002

    Peer Reviews

    CMAQ Review Process: During the past three years, CMAS, in collaboration with EPA scientists, has organized two CMAQ review panel meetings etc. The first CMAQ review meeting was held during December 2003. The second meeting was held during May 2005. The review process usually starts by inviting a number of key scientists to participate in the process. The scientists are selected based on their expertise in accordance with the focus of the review session. After reviewing numerous reports and articles and completing their meeting in Research Triangle Park, North Carolina, the review panel prepares a comprehensive report on their findings and recommendations. EPA then responds to the comments of the reviewers. Final review reports are posted below.

    Congestion Mitigation and Air Quality (CMAQ) Model - Third Review (February, 2007)

    Peer Review Guidance

    The CBP models follow the peer review guidance developed by EPA’s Science Advisory Board (SAB) for regulatory models: http://www.epa.gov/spc/pdfs/modelpr.pdf  and the peer review guidance developed by the Ecological Society of America and endorsed by the American College of Preventive Medicine, American Fisheries Society, American Institute of Biological Sciences, American Public Health Association, American Society of Agronomy, American Society of Limnology and Oceanography, Association of Teachers of Preventive Medicine, Crop Science Society of America, Ecological Society of America, Estuarine Research Federation, Institute of Food Technologists, Soil Science Society of America, Society for Conservation Biology

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