Developing Dissolved Oxygen Criteria to Protect Propagation of Atlantic Sturgeon in Tidal Fresh Delaware River – Jim Hagy, EPA Office of Water
For decades, dissolved oxygen (DO) levels in the tidal-fresh Delaware River have been too low to support propagation of migratory fish, including the endangered Atlantic Sturgeon. In 2022, EPA determined that propagation of oxygen-sensitive migratory fish was an attainable use. Following an intensive period of method development and related policy development, EPA proposed new protective DO criteria in late 2023. EPA finalized the criteria in September 2025. This presentation will describe the physiologically-based cohort model and other aspects of the technical approach that EPA developed to support the rule.
2) Optimizing Nutrient Reductions Across the Long Island Sound Basin – Naomi Detenbeck, EPA Office of Applied Science and Environmental Solutions
This presentation provides an overview of the updates to EPA’s River Basin Export Reduction Optimization Support Tool (RBEROST); a description of linkages to source loads from the USGS dynamic SPARROW model for North Shore watersheds and a groundwater-based model for loads for South Shore watersheds; and preliminary results. RBEROST is designed to enable stakeholders to identify cost-effective solutions to meet watershed nutrient loading targets, considering potential upgrades to septic systems or wastewater treatment plants, implementation of stormwater best management practices or agricultural conservation practices, and restoration of riparian zones. EPA previously released two static versions of RBEROST and is preparing to release an expanded, dynamic version.
Presenters
Jim Hagy, EPA Office of Water
Dr. Hagy is a coastal environmental scientist in EPA’s Office of Water who has conducted scientific research and supported water quality management and policy development related to nutrients, eutrophication, and hypoxia in U.S. coastal waters. His research has addressed science and policy throughout the United States, with particular focus on Chesapeake Bay, the Gulf Coast, and recently Long Island Sound and the tidal-fresh Delaware River. Dr. Hagy’s recent work provided the technical basis for revised dissolved oxygen criteria for the tidal fresh Delaware River, which EPA promulgated in September 2025.
Naomi Detenbeck, EPA Office of Applied Science and Environmental Solutions
Dr. Detenbeck is an ecologist at EPA’s OASES Coastal Science Solutions Division in Narragansett, RI. Her current research is focused on the development and application of decision-support tools for watershed management (WMOST, RBEROST), refinement of spatial statistical temperature models for evaluating restoration options, and development of EPA’s Estuary Data Mapper. Her past research has included work on biogeochemistry, wetlands, landscape ecology, nutrient criteria development, and watershed classification. She holds an M.S. and Ph.D. in Ecology from the University of Minnesota.
Moderators:
- Brenda Rashleigh, EPA Office of Applied Science and Environmental Solutions
- Brenna Friday, EPA Office of Water
