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Bay Health IndexThe Bay Health Index combines the Water Quality Index and the Biotic Index into a single overarching score. This score therefore evenly combines all six indicators (chlorophyll a, dissolved oxygen, water clarity, aquatic grasses, Benthic IBI, and Phytoplankton IBI) into an overall assessment of Chesapeake Bay health.
Chesapeake Bay - Indicator Details:
Index Map
High Resolution Raster Version (PNG)This map shows the 2010 Bay Health Index scores for each of the 15 reporting regions. These scores are used to provide report card grades (A to F) for each of the regions. Most regions of the Bay fell into one of two health grades; poor or moderate. The exceptions were the Patapsco and Back Rivers and the Lower Western Shore (MD) regions, which both had very poor grades. Bay Health Index scores increased in two regions in 2010 compared to 2009, decreased in nine, and remained steady in three. For more information about the overall health of Chesapeake Bay in 2010, please go to the overview page.
This map shows the Bay Health Index scores for each the 15 reporting regions. The Bay Health Index for each reporting region is the average of the Water Quality Index and the Biotic Index scores.
Ranking
Comparison of Bay Health Index scores for 2010 (
) compared to (
)
| Score (%) | |
| 0 20 40 60 80 100 |
| Upper Bay | |
| Lower Bay | |
| James River | |
| Upper Western Shore | |
| Rappahannock River | |
| Overall Bay | |
| Mid Bay | |
| Lower Eastern Shore (Tangier) | |
| Potomac River | |
| Choptank River | |
| York River | |
| Upper Eastern Shore | |
| Patuxent River | |
| Elizabeth River | |
| Patapsco and Back Rivers | |
| Lower Western Shore (MD) |
This figure ranks each region from best to worst for the Bay Health Index scores for 2010. These scores are used to provide report card grades (A to F) for each of the regions. The highest ranked region in 2010 was the Upper Bay and the second highest ranked was the Lower Bay. The Upper Western Shore, which had been the highest ranked for the previous three years, was ranked fourth highest this year.
The lowest ranked region this year was the Lower Western Shore (MD), largely due to a low chlorophyll a and water clarity scores this year. Bay Health Index scores increased in two regions in 2010 compared to 2009, decreased in 11, and remained steady in two. For more information about the overall health of Chesapeake Bay in 2010 go to the overview page.
Excel SpreadsheetTrends Graph
This graph is dynamic, you can: a) show and hide items by clicking them in the legend, b) select year range (click and drag), and c) 
export as an image.
Excel Spreadsheet