Indicator: Water Quality Standards Attainment (1985-2023)

<p><strong>Access the Indicator Materials:</strong><br />- <a target="_blank" href="https://d18lev1ok5leia.cloudfront.net/chesapeakeprogress/chart-assets/AM-2023-Water-Quality-Standards-Attainment-2025-05-01.pdf">Analysis &amp; Methods</a><br />- <a target="_blank" href="https://d18lev1ok5leia.cloudfront.net/chesapeakeprogress/chart-assets/Data-2023-Water-Quality-Standards-Attainment-2025-05-01.xlsx">Data File</a></p><p>Water quality standards attainment in the Chesapeake Bay is estimated by combining three key measures from monitored tidal-water data: dissolved oxygen, water clarity/submerged aquatic vegetation, and chlorophyll a. Because the indicator uses a subset of the data needed for a full regulatory assessment, it is best understood as an estimate of true attainment rather than a complete accounting. The indicator relies on directly measured variables such as salinity, water temperature, dissolved oxygen, Secchi depth, diffuse attenuation coefficient, turbidity, chlorophyll a, and SAV acreage, which are used in assessment methods that include criteria evaluation, spatial mapping, and area-weighted summaries across the Bay’s 92 segments .</p><p><strong>Note: This Indicator supported progress tracking toward the Water Quality Standards Attainment and Monitoring Outcome in the original Chesapeake Bay Watershed Agreement, adopted in 2014. The Watershed Agreement and Water Quality, Standards Attainment &amp; Monitoring Outcome were revised in 2025.</strong></p>