NEWSLETTER

Chesapeake Assessment Scenario Tool

CAST Newsletter: July 2025

Tips and information to facilitate environmental restoration efforts in the Chesapeake Bay watershed

Did You Know?

Did you know the BMP Targeting Maps now include 2024 Progress data? These updated maps use CAST delivery factors and nutrient/sediment loads to highlight land-river segments where BMPs can have the greatest impact. Darker areas on the maps show where high loads and high delivery factors overlap—ideal for targeting efforts. Explore the updated maps to see where restoration actions matter most.

CAST Webinars and Training

Upcoming Webinars

We are taking a summer break and will resume CAST webinars in September.

In-person trainings are available upon request.

Available Training Videos

May's CAST webinar focused on urban BMPs and rising temperatures. As communities across the Chesapeake Bay watershed face rising air and water temperatures, urban areas are especially vulnerable to the combined impacts of heat, flooding, and pollution. This webinar explores how urban BMPs--such as tree planting, rain gardens, and infiltration practices--can support both climate resilience and water quality goals. We highlight findings from the Scientific and Technical Advisory Committee's (STAC) Rising Temperatures workshop report, including how temperature affects watershed health and which BMPs offer key co-benefits for cooling and stormwater management. We also demonstrate how to identify these climate-smart practices in CAST and estimate their nutrient and sediment reduction potential, helping planners integrate climate and water quality solutions more effectively.

This, and other past training videos on topics ranging from buffers to targeting nutrient reductions, are available in the Learning section of CAST under 'Free Training Videos'. Amongst the variety of training content available, there are also short videos on topics like 'Where do I start,' under CAST 101 - Getting Started.

Chesapeake Bay Watershed Success Story

Virginia awards $67M to fight flooding across the state: The Virginia Department of Conservation and Recreation awarded $67 million in grants from the state’s Community Flood Preparedness Fund on July 1. Read more about this success story on the Bay Journal website.

Does your organization have a Chesapeake Bay Watershed success story you'd like to share? If you have a story you would like to see in the next CAST Newsletter, submit an article using the 'Contact Us' feature from any page of the CAST website.

Chesapeake Bay Program Deadlines

Progress toward the Bay TMDL

The Chesapeake Bay Deadlines refer to the major jurisdictions' annual reporting of new BMPs implemented, and existing BMPs verified as functioning in the watershed. BMP implementation information is used to create annual progress scenarios using CAST and to make assessments and report out the estimated impacts of restoration efforts.

  • October 1, 2025: Federal facility BMP reports due to the jurisdictions.
  • No later than December 1, 2025: Final BMP submissions for previous July 1 - June 30 data period due from jurisdictions for the 2025 Progress Phase 6 model assessment - both wastewater data and non-wastewater BMPs. Wastewater data includes the categories CSO, bio-solids, spray irrigation, large onsite septic systems, and rapid infiltration.
  • December 2025: Progress reports and resubmission reminders are available each Friday. Calls with state technical leads are scheduled to resolve issues.
  • January 2026: Progress reports and resubmission reminders continue. Calls with state technical leads continue.
  • February 6, 2026: Final opportunity for states to update BMP data.
  • February 9, 2026: Final progress run information available to jurisdictions - needed for outside reporting of progress on commitments to keep results relevant.
  • May 8, 2026: 2025 Progress finalized and released on CAST. Progress may be delayed due to unresolved issues surrounding the verification assessments.

Updates to CAST

New features:

The manure transport BMP logic now allows manure to be transported into areas where there are no animals and no crops. Previously, that manure was not counted in the area.

Security updates were made.

This update affects the loads in the 2024 Progress scenario in Charlottesville and Alexandria, Virginia.

A full list of changes is available on CAST's Upgrade History. The new CAST version is Phase 6 - 7.14.3.

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