Upcoming Meetings

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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.

Core Values

The Modeling Workgroup has a responsibility to the Chesapeake Bay Program Partnership to provide state-of-the-art decision-support modeling tools that are built through community and participatory principles. The responsible planning and management of resources to provide the best available decision-support modeling tools requires the Modeling Workgroup members and participants to adhere to the core values of:

  • Integration - Integration of most recent science and knowledge in air, watershed, and coastal waters to support ecosystem modeling for restoration decision making.
  • Innovation - Embracing creativity and encouraging improvement in the development and support of transparent and robust modeling tools.
  • Independence – Making modeling decisions on the basis of best available evidence and using the most appropriate methods to produce, run, and interpret models, independent of policy considerations.
  • Inclusiveness - Commitment to an open and transparent process and the engagement of relevant partners, that results in strengthening the Partnership’s decision making tools.

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:

Projects and Resources

Midpoint Assessment

New web page summarizes the priorities and identifies lead researchers for each effort. The descriptions are brief with links to more detailed workplans.

Phase 7 Model Development

The Chesapeake Bay Program is updating its modeling and analysis tools used in the Chesapeake Bay TMDL. For more information, please visit the Phase 7 Model Development Webpage.

Tributary Summaries

The Chesapeake Bay Program and its partners produce tributary basin summary reports for the Bay’s 12 major tributaries using tidal monitoring data from more than 130 monitoring stations throughout the mainstem and tidal portions of the Bay. These reports use water quality sample data to summarize 1) How tidal water quality (TN, TP, DO, Chlorophyll a, Secchi Depth) has changed over time, 2) How and which factors may influence water quality change over time, and 3) Recent research connecting observed changes in aquatic conditions to its drivers.

These documents can be found on the CAST webpage here.

Phase 6 Watershed Model Documentation

The model documentation is available as a single downloadable document (78 MB) or as separate model sections (see Below). The suggested citation is: Chesapeake Bay Program Office, 2020. Phase 6 Dynamic Watershed Model and CAST-17 Documentation. https://cast.chesapeakebay.net....

1. Overview

2. Average Loads
Appendix 2A: Agricultural Loading Rates

3. Terrestrial Inputs
Appendices ABCDG: Terrestrial Inputs
Appendix 3E: Swine Characterization Study Final Report
Appendix 3F: Turkey Litter Nutrients
Appendix 3H: Atmospheric Deposition

4. Sensitivity
Appendix 4A: Sensitivity analysis of the HSPF AgChem Model
Appendix 4B: Sensitivity analysis for all land uses

5. DRAFT Land Use
DRAFT Land Use Appendix

6. Best Management Practices
Appendix 6A: BMP Expert Panel Protocol
Appendix 6B: Order of Load Source Change Credit

7. Land to Water

8. Direct Loads

9. Stream to River
Appendix 9A: Alternate Stream to River Methods
Appendix 9B: Excluded Reservoir Catchments

10. River to Bay and Temporal Simulation
Appendix 10A: Ftables and Stations
Appendix 10B: Calibration Stations
Appendix 10C: Nutrients and Sediment Calibration Targets
Appendix 10D: HSPF River Water Quality Parameters
Appendix 10E: Estuarine Model Linkage

11. Physical Setting
Appendix 11A: List of Segments

12. Applications

13. Reviews

14. References

15. Errata

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Workgroups and Action Teams


Dave Montali (Chair), Tetra Tech
601 57th St SE
Charleston, West Virginia 25304

Email:  dave.montali@tetratech.com
Phone:  (304) 414-0054 x104
Mark Bennett (Chair), U.S. Geological Survey (USGS)
1730 East Parham Road
Richmond, Virginia 23228

Email:  mrbennet@usgs.gov
Phone:  (804) 261-2643
Lewis Linker (Coordinator), Modeling Coordinator, U.S. Environmental Protection Agency
1750 Forest Drive Suite 130
Annapolis, Maryland 21401

Email:  linker.lewis@epa.gov
Phone:  (410) 267-5741
Alex Gunnerson (Staffer), GIS Analyst, U.S. Geological Survey (USGS)
1750 Forest Drive Suite 130
Annapolis, Maryland 21401

Email:  agunnerson@chesapeakebay.net
Bill Keeling, Virginia Department of Environmental Quality
P O Box 1105
Richmond, Virginia 23218

Email:  william.keeling@deq.virginia.gov
Phone:  (804) 698-4342
Gary Shenk, Hydrologist, U.S. Geological Survey (USGS)
1750 Forest Drive Suite 130
Annapolis, Maryland 21401

Email:  gshenk@chesapeakebay.net
Phone:  (410) 507-2681
Peter Tango, Monitoring Coordinator, U.S. Geological Survey (USGS)
1750 Forest Drive Suite 130
Annapolis, Maryland 21401

Email:  ptango@chesapeakebay.net
Phone:  (410) 267-9875
George Onyullo, District of Columbia Department of Energy & Environment (DOEE)
1200 First St. NE
5th Floor
Washington, District of Columbia 20002

Email:  george.onyullo@dc.gov
Jesse Bash, U.S. Environmental Protection Agency
Durham, North Carolina 27709

Email:  bash.jesse@epamail.epa.gov
Karl Berger, Metropolitan Washington Council of Governments
777 North Capitol Street, NE
Suite 300
Washington, District of Columbia 20002

Email:  kberger@mwcog.org
Cassie Davis, New York State Department of Environmental Conservation
625 Broadway, 4th Floor
Albany, New York 12233-3507

Email:  Cassandra.davis@dec.ny.gov
Phone:  (518) 402-8283
Mukhtar Ibrahim, Metropolitan Washington Council of Governments
777 North Capitol St NE #300
Washington, District of Columbia 20002

Email:  mibrahim@mwcog.org
Bill Ball, Chesapeake Research Consortium
242 Garland Hall
Baltimore, Maryland 21218

Email:  ballw@chesapeake.org
Carl Cerco, U.S. Army Corps of Engineers (USACE)
3909 Halls Ferry Road
Vicksburg, Mississippi 39180

Email:  carlcerco@outlook.com
Dinorah Dalmasy, Maryland Department of the Environment
1800 Washington Boulevard
Baltimore, Maryland 21230

Email:  dinorah.dalmasy@maryland.gov
Phone:  (410) 537-3699
Raleigh Hood, University of Maryland Center for Environmental Science
P.O. Box 775
Cambridge, Maryland 21613

Email:  rhood@hpl.umces.edu
Phone:  (410) 221-8434
Carl Friedrichs, Virginia Institute of Marine Science (VIMS)
Rt. 1208 Greate Rd.
Gloucester Point, Virginia 23062-1346

Email:  cfried@vims.edu
Hassan Mirsajadi, Delaware Department of Natural Resources and Environmental Control
89 Kings Hwy
Dover, Delaware 19901

Email:  Hassan.Mirsajadi@state.de.us
Bill Brown, Commonwealth of Pennsylvania
400 Market Stree
Harrisburg, Pennsylvania 17105

Email:  willbrown@pa.gov
Lauren Townley, New York State Department of Environmental Conservation
625 Broadway
Albany, New York 12233

Email:  lauren.townley@dec.ny.gov
Phone:  (518) 402-8283
Scott Heidel, Pennsylvania Department of Environmental Protection
400 Market Street
Harrisburg, Pennsylvania 17101

Email:  scheidel@pa.gov
Phone:  (717) 772-5647