Welcome to the Virginia Assessment Scenario Tool

VAST has merged with CAST. Your data and login credentials are active in CASTTool.org. All the functionality that you are accustomed to remains the same. Click here to access CAST.

The Virginia Assessment and Scenario Tool (VAST) allows users to rapidly develop scenarios with varying best management practices.

Output includes nitrogen, phosphorus, and sediment loads from all sectors and sources, acres of each BMP, and costs for the scenario for any area in the Chesapeake Bay Watershed. These loads are consistent with the Chesapeake Bay Program’s Watershed Model. VAST also provides inputs to the Chesapeake Bay Program computer models.

Users can compare among scenarios to select the practices that reduce the most pollution, are most cost-effective, and target these practices to the highest impact areas. Scenarios can be used for TMDL Watershed Implementation Plans, Milestones, or for local planning purposes.

FAQs about the transition to Phase 6