Upcoming Meetings

Scope and Purpose


The AMT will provide agricultural modeling assistance to support the (AgWG) through the development of the Phase 7 (WSM) inputs.


Support will be accomplished by providing the capacity for in-depth analyses of agricultural items of interest brought forward by the partnership. From these in-depth analyses, technical decisions will be made regarding the processing of input data in the Phase 7 WSM. The functions of the group will be to:

  • Review data preprocessing methods and agricultural inputs to ensure that Phase 7 WSM utilizes the best available information to reflect agricultural conditions in the watershed and how they change through time.
  • Review current [Phase 6] WSM assumptions related to the applications of nutrients on agricultural lands and determine if changes are appropriate for Phase 7. Several examples of relevant topics include: manure and fertilizer nutrient inputs; legume fixation; crop application goals; cover-factors for RUSLE*; climate change considerations; and soil phosphorus data.
  • Consideration of land use/load source category changes.
  • Coordinate with USDA agencies to identify supporting model structures, analysis methods and agricultural databases.
  • Make decisions on what the most appropriate agricultural input data are for the Phase 7 WSM.

Projects and Resources

Agricultural Modeling Subcommittee Phase 6

The following information refers to the Agricultural Modeling Subcommittee, the precursor to the current Agricultural Modeling Team. Please review the following as reference material describing this group to familiarize yourself with the foundational information that has led us to where we are today.

Phase 6 Scope and Purpose

The Agricultural Modeling Subcommittee provides enhanced agricultural modeling assistance to support the Agriculture Workgroup and the workgroup's Expert Review Panels on technical decisions regarding the development of the Phase 6 modeling tools for the TMDL Mid-Point Assessment in 2017. Functions include:

  • Provide agricultural modeling support to the Agriculture Workgroup's Expert Review Panels, coordinate cross-modeling support between the Chesapeake Bay Program Office and USDA agencies, and assist with the development and review of panel recommendations.
  • Review current agricultural data inputs to Scenario Builder and the Watershed Model. Consider recommendations for new or improved data sources resulting from the Agriculture Workgroup’s 2013 Modeling Workshop. Make recommendations for data sources to be used post-2017.
  • Review current Scenario Builder and Watershed Model assumptions related to the fate and transport of nutrients on agricultural lands. Some specific assumptions that will be studied include: the placement of excess manure on agricultural lands; timing and applications of nutrients; percent of land available for manure application; etc. Make recommendations to the Agriculture Workgroup for new algorithms or process assumptions related to the fate and transport of nutrients on agricultural lands to be used post-2017.
  • Coordinate with USDA agencies to identify opportunities to collaborate or integrate with USDA modeling tools and databases for providing sources of agricultural data, alternative modeling structures and analysis methods.

AgWG/AMS Review of Phase 6 Model

This project page is the repository for the Phase 6 model, its documentation, as well as files and links to Tableau pages, specifically as it related to the Agriculture Workgroup (AgWG) and Agricultural Modeling Subcommittee (AMS). Please email Lindsey Gordon (gordon.lindsey@epa.gov) with any questions you may have.

The .pdf 'Draft Final Phase 6 Model Review: Comments Received for AMS' will be routinely updated and reposted as additional comments are received.


All documentation files will be uploaded to this FTP site to assist in partnership review of Phase 6: https://archive.chesapeakebay.net/?prefix=Modeling/Phase6/Draft_Phase_6/Documentation/

Documentation of decisions made by the AgWG and AMS pertaining to the Phase 6 modeling tools is available below and will be updated with any additional decisions.


A summary PDF of calibration results has been generated and is available for download (large file): https://archive.chesapeakebay.net/Modeling/Phase6/Draft_Phase_6/Watershed_Model/WSM_Outputs/Calibration_Figures/00_Calibration_Figures_All_Phase6Draft.pdf

Other detailed calibration results for each calibrated parameter and river segment can be found in a separate FTP folder: https://archive.chesapeakebay.net/?prefix=Modeling/Phase6/Draft_Phase_6/Watershed_Model/WSM_Outputs/Calibration_Figures/

Further detailed calibrated output for the watesrhed can be found in csv files located at this FTP site: https://archive.chesapeakebay.net/?prefix=Modeling/Phase6/Draft_Phase_6/Watershed_Model/WSM_Outputs/Summary_Loads/

Land use files can be found at this ftp site: https://archive.chesapeakebay.net/?prefix=Modeling/Phase6/Draft_Phase_6/Land_Use/

Watershed Model Inputs

Links to the sites for Watershed Model Inputs can be found at these web pages:

FAQ regarding Modeling Tools: https://mpa.chesapeakebay.net/Phase6FAQ.html

Graphical Interface for Phase 6 Model Inputs: https://mpa.chesapeakebay.net/Phase6DataVisualization.html

CAST Homepage: http://cast.chesapeakebay.net/

Phase 6 Soil Phosphorus Figures: https://archive.chesapeakebay.net/Modeling/soil-p-history/fig/

Model Review Process

The process by which the partnership can most effectively submit comments and provide feedback to the development of the Phase 6 model will be outlined in a continuously updated document found below. The schedule of upcoming webinars is also provided below and in the attached document. Please contact Lewis Linker (llinker@chesapeakebay.net) or Kyle Hinson (khinson@chesapeakebay.net) with any questions.

Phase 6 Sediment Simulation Webinar: April 19, 2017, 1 PM - 3 PM (link)

Phase 6 Integrated Models and Decision Framework Overview Webinar: May 9, 2017, 1 PM - 3 PM (link)

Phase 6 Poultry Inputs Webinar: May 24, 2017, 1-3 PM (link)

Phase 6 Inputs Webinar: May 25, 2017, 1 PM - 3 PM (link)

Phase 6 Loads Webinar: June 1, 2017, 1 PM - 3 PM (link)

Phase 6 Physical Transport Webinar: June 20, 2017, 1 PM - 3 PM (link)

Phase 6 Scenario Builder Review

Scenario Builder is a data management tool that provides estimates of land use acres, nutrient inputs, cropland attributes, and best management practice (BMP) implementation data to the Chesapeake Bay Program Partnership's Phase 6 Watershed Model. The documentation and initial application rates to crops that are provided in the link below will help inform a full partnership review of the tool's documentation, during which the Agricultural Modeling Subcommittee (AMS) hopes to receive comments that could result in improvements to the tool in the spring and summer of 2016.

June 23, 2016:
The Agriculture Workgroup requested two nutrient spread application procedures be tested in advance of its July 20-21 face-to-face meeting. Nutrient applications from inorganic fertilizer, manure and biosolids from both versions are now available for download at https://archive.chesapeakebay.net/?prefix=Modeling/Phase6/Ph6Calibration_Beta2/20160401/inputs/ScenarioBuilder/. The two procedures are briefly described below.

  • The first procedure, known as Beta 3a, relies upon an estimate of fertilizer sales across the watershed, and distributes those sales to counties based upon dollars spent by a county, as reported by the Census of Agriculture, and inorganic crop nutrient need after manure and biosolids applications are made. Using this method, the total pounds of inorganic fertilizer applied across the watershed are equal (never above or below) the total pounds of fertilizer sales estimated across the watershed.
  • The second procedure, known as Beta 3b, applies inorganic fertilizer to fulfill crop nutrient need after manure and biosolids applications are made. Using this method, the total pounds of inorganic fertilizer applied across the watershed may exceed or be lower than the estimated fertilizer sales across the watershed. This procedure is similar in method to the current Phase 5.3.2 inorganic fertilizer application procedure.
  • States are encouraged to review the results of each procedure prior to the July 20 meeting. A detailed analysis of the two methods, including areas of disagreement between the two methods, will be provided at the meeting.

July 13, 2016:

The purpose of the webinar was to review the inputs to the Beta 3 version of Scenario Builder, review the two methods to representing nutrient spread that were used in Beta 3a and 3b, provide a summary of the results, and to answer any questions that AgWG members and interested parties had when interpreting these results.

Materials from the webinar are available through the following link: https://www.chesapeakebay.net/channel_files/24182/webinar_presentation.pdf

August 23, 2016:

At its July meeting, the Agriculture Workgroup approved the use of AAPFCO fertilizer sales data to inform applications of inorganic fertilizer by county during the calibration period (1984-2013) of the Phase 6 Watershed Model. The Workgroup approved distributing total pounds of inorganic fertilizer sold across the watershed to counties based solely upon inorganic crop application goals left over after applications of biosolids and manure. The files attached below ('Beta 3a1-XXX.xlsx') provide applications and legume fixation by land use and crop following these new recommendations.

Improvements for the April calibration include:
• Inorganic fertilizer was distributed to crops only after all BMPs were simulated that would impact the amount of manure available to crops and the amount of agricultural acres with remaining nutrient application needs.
• Manure mineralization rates, which impact the amount of manure nutrients available to crops, were updated to reflect typical nutrient management mineralization rates by decade.
• Manure recoverability, or the amount of manure generated in a barnyard that can be made available to crops, before and after the implementation of Animal Waste Management Systems was updated to reflect estimates provided in http://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs143_012131.pdf
• Acres of barnyards or feeding facilities were updated to reflect the Bay Program’s best estimates per animal type.
• Nutrient application goals for the minor crops, emmer, spelt and triticale, were based upon state-recommended applications on a per acre basis as very little yield data was available to vary the application goals by annual yield.

December 12, 2016:

The Beta 4 Input Data, including nutrients applied by land use and by crop type, are now available to download from the FTP site using the following link:


Please use the link below to access a draft version of Scenario Builder documentation and initial application rates to land uses crops for the January, 2016 initial calibration run.

Download the zip file titled: "Ph6CalibrationFiles_20151109.zip"
To access the Scenario Builder draft documentation, download the file: 'SBV6Documentation_01212016.pdf'

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Zach Easton (Chair), Virginia Tech
222 Burruss Hall
Blacksburg, Virginia 24061

Email:  zeaston@vt.edu
Thomas Butler (Coordinator), Life Scientist, U.S. Environmental Protection Agency - Region 3
1750 Forest Drive Suite 130
Annapolis, Maryland 21401

Email:  butler.thomas01@epa.gov
Phone:  (410) 267-5797
Jackie Pickford (Staffer), GIS Analyst, U.S. Geological Survey (USGS)
1750 Forest Drive Suite 130
Annapolis, Maryland 21401

Email:  pickford.jacqueline@epa.gov
Gary Shenk, Hydrologist, U.S. Geological Survey (USGS)
1750 Forest Drive Suite 130
Annapolis, Maryland 21401

Email:  gshenk@chesapeakebay.net
Phone:  (410) 507-2681
Mark Dubin, Senior Agricultural Advisor, University of Maryland Cooperative Extension
1750 Forest Drive Suite 130
Annapolis, Maryland 21401

Email:  mdubin@chesapeakebay.net
Phone:  (410) 267-9833
Olivia Devereux, Environmental Scientist, Devereux Environmental Consulting
9219 Mintwood Street
Silver Spring, Maryland 20901

Email:  olivia@devereuxconsulting.com
Phone:  (301) 325-7449
Ruth Cassilly, Non-point Source Policy Analyst, University of Maryland Cooperative Extension
1750 Forest Drive Suite 130
Annapolis, Alabama 21401

Email:  rcassilly@chesapeakebay.net
Phone:  (410) 267-5707
Jessica Rigelman, Environmental Data Analyst
1750 Forest Drive Suite 130
Annapolis, Maryland 21401

Email:  jrigelman@j7llc.com
Phone:  410-991-0719
Chris Brosch, Delaware Department of Agriculture
2320 S. Dupont Highway
Dover, Delaware 19901

Email:  chris.brosch@state.de.us
Phone:  (302) 698-4555
Alisha Mulkey, Maryland Department of Agriculture
50 Harry S. Truman Pkwy.
Annapolis, Maryland 21401

Email:  alisha.mulkey@maryland.gov
Phone:  (410) 841-5866
Cassandra Davis, New York State Department of Environmental Conservation
625 Broadway
Albany, New York 12233

Email:  cassandra.davis@dec.ny.gov
Scott Heidel, Pennsylvania Department of Environmental Protection
400 Market Street
Harrisburg, Pennsylvania 17101

Email:  scheidel@pa.gov
Phone:  (717) 772-5647
Dave Montali, Tetra Tech
601 57th St SE
Charleston, West Virginia 25304

Email:  dave.montali@tetratech.com
Phone:  (304) 414-0054 x104
Jeff Sweeney, Integrated Analysis Coordinator, U.S. Environmental Protection Agency
1750 Forest Drive Suite 130
Annapolis, Maryland 21401

Email:  sweeney.jeff@epa.gov
Phone:  (410) 267-9844
Ken Staver, University of Maryland
Wye Research and Education Center
P.O. Box 169
Queenstown, Maryland 21658

Email:  kstaver@umd.edu
Phone:  (410) 827-8056 x111
Tamie Veith, USDA Agricultural Research Service

Email:  tamie.veith@usda.gov
Candiss Williams, USDA Natural Resources Conservation Service (NRCS)

Email:  candiss.williams@usda.gov
Alex Soroka, U.S. Geological Survey (USGS)

Email:  asoroka@usgs.gov
Tim Larson, Virginia Department of Conservation and Recreation

Email:  tim.larson@dcr.virginia.gov