Case Studies

This library is a compilation of the case studies that are highlighted at the bottom of relevant pages throughout this N-STEPS Online tool. The case studies provide examples of decisions that states made during specific stages of the numeric nutrient criteria development process.

Click on each card below to open a case study summary. For more detail, refer to the original sources, which are cited and accessible in the resource library. Results can be filtered using the Search feature, and also by clicking water body, parameter, and analysis approach icons.

For progress on the adoption of numeric nutrient criteria for all states and territories, please visit EPA’s Nutrient Policy and Data page.



Search Case Study Results (e.g., Water body name, state)
Analysis Approach
Nutrient Parameter
Water Body Type

San Francisco Bay Endpoints

Assessment Framework for SF Bay

Nutrient Effects in CA Streams

Red River of the North

Recommended Criteria for WV Lakes

Virginia Freshwater Nutrient Criteria

Proposed Criteria for Tampa Bay

Tidal James River Chl-a Criteria

St. Louis Bay, MS

SAV Targets in MD and VA Coastal Bays

Nitrogen Thresholds, MA Embayments

Eutrophication in Waquoit Bay, MA

Seagrass Recovery in Tampa Bay

Low DO in Skidaway River

Low DO in Hood Canal, WA

Texas Brown Tide

Chl-a in San Francisco Bay

Nutrient Trends in MD Coastal Bays

Nutrients Threaten Coral Reefs

Monitoring Agricultural BMPs

Casco Bay Water Quality Index

Nutrient TMDL for Klamath River, OR

Chesapeake Bay Criteria

NNC Development for Desert Streams

Bow River, Alberta

Nutrients During Low-flow Conditions

Nutrient TMDL in the Rockies

TN Ecoregional Nutrient Criteria

Florida Everglades Phosphorus

Lake Champlain TP Criteria

This website is in beta. Information on this website is not final and is subject to change