Browse History: Bay Health Index (2008)

Bay Health Index

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

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Editable Vector Version (SVG)

High Resolution Raster Version (JPG)

Station Data Download (Excel)

This map shows the 2008 Bay Health Index scores for each of the 15 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 Upper Western Shore, which had a moderate-good score and the Lower Western Shore which had a very poor grade. Bay Health Index scores increased in 8 regions in 2008 compared to 2007 and decreased in 5. For more information about the overall health of Chesapeake Bay in 2008 go to the overview page.

Creating this map
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 2008 (

) compared to (

)

	Score (%)
	0 20 40 60 80 100

Upper Western Shore
Upper Bay
James River
Potomac River
Lower Bay
Overall Bay
Lower Eastern Shore (Tangier)
Rappahannock River
Mid Bay
Choptank River
Upper Eastern Shore
York River
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 2008. These scores are used to provide report card grades (A to F) for each of the regions. The highest ranked region in 2008 was the Upper Western Shore (this region was also the highest ranked region in 2007) and second highest ranked was the Upper Bay.

One of the reasons these two areas rank so highly is abundant aquatic grasses coverage. 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 8 regions in 2008 compared to 2007 and decreased in 5. For more information about the overall health of Chesapeake Bay in 2008 go to the overview page.

Excel Spreadsheet

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).

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Editable Vector Version (SVG)

Excel Spreadsheet

The EcoCheck report card has three main sections: Overview, Region Summaries, and Indicators/Indices.

Click the next (>>) button above to get a guided tour of some of the key features of the report card card website.

This map shows the Health Index grades for all the reporting regions, but mousing over each region also provides a text summary and clicking will direct the user to the region summary page with more details about the health of that region.

The region rankings table provides an easy way to visualize the Water Quality Index (WQI), Biotic Index (BI), and overall Bay Health Index (BHI) for all regions. Once again, mousing over provides extra information - try it yourself and see what is displayed. Region names, and indicator icons also serve as navigation links.

The comparison graph allow users to compare the current report card to previous year's scores. Mousing over provides actual percentages and bars provide a direct link to the region's summary page.

Now you're at the region summary page for the Overall Bay. This page details the scores for all the individual indicators, as well as a dynamically generated conceptual diagram (please scroll down the page to view). Even this diagram has more information onmouseover, and has direct links to the detailed indicator pages. There is also a vector (SVG) version of the diagram available for download so you can edit this in your favorite illustration software.

The trends graph shows all the indicators and indices for the selected region since 1986. You can dynamically turn on and off each of the indicators to show only the data you are most interested in. Mousing over the graph shows percentage scores and you can zoom in for finer detail in certain time periods. There is also a fully editable vector (SVG) version of the graph available for download, along with an Excel spreadsheet of the data.

This is the threshold map for Chlorophyll a. This map is zoomable and panable and also available in fully editable vector (SVG) and JPG versions.

The trends graph on the indicator pages shows the indicator and indices data for each region since 1986. By default, only the Overall Bay region is displayed, but you can turn on as many of the other regions as you wish.

The watershed stream health page has several tabs, but the key one is the interactive Google maps version of the data.

Please wait while the map loads and then test out the ratings toggle options and the "zoom to area" functionality (click on the magnifying glass and then click and drag to select the are to zoom to).