Indicator: Modeled Nutrient and Sediment Loads to the Chesapeake Bay (1985-2024)

<p><strong>Access the Indicator Materials:</strong><br />- <a target="_blank" href="https://d18lev1ok5leia.cloudfront.net/chesapeakeprogress/Analysis-and-Methods_2024_Modeled-Load-Reduction-Indicator_FINAL.docx">Analysis &amp; Methods</a><br />- <a target="_blank" href="https://d18lev1ok5leia.cloudfront.net/chesapeakeprogress/chart-assets/modeled-nitrogen-loads-to-the-chesapeake-bay-2/Data_2024_MLRI_FINAL.xlsx">Data File</a></p><p>Progress for this indicator is estimated using up-to-date wastewater discharge data and Best Management Practice (BMP) implementation data reported annually to EPA’s Chesapeake Bay Program Office by Bay watershed jurisdictions. The Chesapeake Bay Program Office assesses current nutrient and sediment load conditions using Phase 6 of the Watershed Model, also known as the Chesapeake Assessment Scenario Tool (CAST). This model estimates pollutant loads from major sources, including wastewater, agricultural runoff, urban and suburban runoff, septic systems, and atmospheric deposition, based on average weather conditions. The data are used for planning, tracking, research, long-term monitoring, and estimating progress toward the partnership’s adjusted Interim Targets under changing environmental conditions, as well as the jurisdictions’ Phase III Watershed Implementation Plans (WIPs). The Phase III WIPs and the adjusted Interim Targets are designed to achieve Bay water quality standards</p><p><strong>Note: This Indicator supported progress tracking toward the 2025 Watershed Implementation Plans (WIPs) Outcome in the original Chesapeake Bay Watershed Agreement, adopted in 2014. The Watershed Agreement and Reducing Excess Sediment, Nitrogen &amp; Sediment Outcome were revised in 2025.</strong></p>