Chesapeake Bay Scenario Builder (Scenario Builder)

Objective The Chesapeake Bay Scenario Builder (Scenario Builder), a decision support tool, facilitates the creation of input decks for the Chesapeake Bay Watershed Model management scenarios.

Developer The Bay Scenario Builder tool was developed by USEPA, the Chesapeake Bay Program Office and a private consultant.

Contact information Chris Brosch,, 410-267-5707, Chesapeake Bay Program Office, 410 Severn Ave. , Suite 112, Annapolis, MD 21403

Inputs The Bay Scenario Builder tool utilizes input data from diverse sources, including BMP types, quantities and locations from Bay jurisdictions, cropland and pasture land data from USDA-NASS Agricultural Census, livestock population and location data from USDA-NASS Agricultural Census and Bay jurisdictions, biosolids applications from Bay jurisdictions, and septic systems.

Outputs The Bay Scenario Builder tool generates information that is used with other watershed characteristic data to simulate nutrient and sediment loads related to animal production areas, application of manures and fertilizers to cropland and turf grass, septic inputs, plant growth/uptake, best management practice (BMP) implementation, atmospheric deposition of nutrients, and discharges from wastewater facilities.

User The Bay Scenario Builder tool is used by USEPA and the Chesapeake Bay Program Office for the development and implementation tracking of the Chesapeake Bay TMDL, and to assist the Bay jurisdictions in developing the supporting Watershed Implementation Plans (WIPs).

Scales of Relevance The Bay Scenario Builder tool can process data at a variety of scales, including land-river segment, river segment, land segment, county, state and basin, tributary strategy basin or state.

Other The Bay Scenario Builder and Watershed Model tools are currently being augmented to several compatible tools through the Maryland Assessment and Scenario Tool (MAST) and the Chesapeake Assessment and Scenario Tool (CAST). These tools will provide direct access to state agency staff and local planning organizations for use in developing and analyzing management scenarios.

Sponsors/funders USEPA and the Chesapeake Bay Program Office.