Chesapeake Bay 2014-2023 Trends and Change in Flow-Normalized Loads Per Acre

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These maps display the 10-year trends and change in flow-normalized per-acre loads for nutrients and sediment across the Chesapeake Bay Watershed from 2014 to 2023. 

Loads are defined as the mass of nutrient or sediment passing a monitored location per unit time. Flow-normalized loads are used to determine trends in water quality over time. A per-acre load, also known as a yield, is load divided by the area of the watershed upstream of the monitored location.

What is a flow-normalized load?

Loads are related to streamflow, so years with more precipitation and therefore higher streamflow tend to have higher loads. To understand how water quality is changing due to human actions and not due to variability in weather, loads need to be flow-normalized to factor out the influence of streamflow. 

Learn more about Chesapeake Bay Water-Quality Loads and Trends and the USGS Nontidal Network.