The 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 habitat health.
Chesapeake Bay - Indicator Details:
Index Map
This map shows the 2006 Bay Health Index scores for each the 15 regions. Most regions of the Bay fall into one of two health grades; poor or moderate, with the exception being the Patapsco and Back Rivers region, which had a very poor score. Moderate scores were recorded for the James River, Upper Bay, Lower Bay, and Lower Eastern Shore (Tangier) regions. The number of poor and moderate scoring regions in 2006 was similar to that recorded in 2003, an above average flow year, indicating that the overall health in 2006 may have been affected by the extreme weather conditions (dry spring and wet summer).
This map shows the 2006 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 2006 (
| Score (%) | |
| 0 20 40 60 80 100 |
| Upper Bay | |
| James River | |
| Lower Eastern Shore (Tangier) | |
| Lower Bay | |
| Overall Bay | |
| Upper Western Shore | |
| Potomac River | |
| Elizabeth River | |
| Upper Eastern Shore | |
| Mid Bay | |
| Rappahannock River | |
| York River | |
| Patuxent River | |
| Lower Western Shore (MD) | |
| Choptank River | |
| Patapsco and Back Rivers |
This figure ranks each region from best to worst for the Bay Health Index. The Upper Bay had the highest score because of the high Water Quality Index and Biotic Index scores. The Lower Eastern Shore (Tangier) had the second highest score, but was 10% behind the Upper Bay. Most regions received either a moderate or poor score, with the Patapsco and Back Rivers the only region to score very poorly.
Trends Graph
This graph is dynamic, you can check and uncheck regions (
checkboxes in legend), select year range (
click and drag), and export as an image (right click).