Nutrient and Sediment Trends

Trend Map (PDF)*
Trend Statistics (PDF)*
Trend Statistics (Excel file)

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SRBC estimates trends in nutrients and sediment as part of the Chesapeake Bay Program's annual trend update. Water-quality data from the Susquehanna Nutrient Assessment Program monitoring stations were used to calculate trends in: (1) monthly mean flow (FLOW); and (2) flow-adjusted concentration (FAC) for nitrogen, phosphorus and suspended sediment.

Trends in:

• FLOW indicates the natural changes in hydrology, which affects the observed concentrations and the estimated loads of nutrients and sediment.
• FAC indicates that changes have occurred in the processes that deliver constituents to the stream. After the effects of flow are removed, this is the concentration that relates to the nutrient reduction management actions taking place in the watershed.

There are two patterns that emerge when looking at trends: those water quality trends that relate to nutrient reduction from management actions and those that relate to the interactions of water quality, habitat and biological responses. For sites in the Susquehanna River Watershed, FACs generally indicate that there is a downward (improving) trend in total nitrogen, total phosphorus and suspended sediment as a result of best management practices or actions.