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Browse History: Overview (2011)

Chesapeake Bay - Overview:



Synopsis


Report Card Cover
Bay Health Index
Benthic Index of Biotic Integrity Icon
38%
D+
Poor ecosystem health. The overall health of the Bay declined for the second year in a row, from 42% in 2010 to 38% in 2011. Five of the six indicators—dissolved oxygen, chlorophyll a, water clarity, aquatic grasses, and benthic community—declined in score, while phytoplankton community scores increased this year.

Poor 2011 Chesapeake Bay health

Chesapeake Bay health in 2011 (D+; 38%) was the second lowest since assessments began in 1986. This poor report card score was due to the lowest measured water clarity score, second lowest chlorophyll a score, and a large drop in the aquatic grass score. Both mainstem and tributary regions had lower scores than in 2010. For the first time, the Elizabeth River received a grade, an F.


A sequence of events contributed to 2011 health

timeline showing bay health events
Tropical Storm Lee effects: Flood waters from the Susquehanna River watershed during Tropical Storm Lee brought up to 4 centimeters (~1½ inches) of sediments to the Upper Bay.1 The Susquehanna River flow was strong enough to scour tons of sediments from behind the Conowingo Dam on the Lower Susquehanna River. This new layer of muddy sediments may affect next year's aquatic grass and benthic community scores.
1Preliminary findings by Dr. Cindy Palinkas, UMCES

Restoration efforts: There have been major accomplishments regarding Chesapeake Bay restoration in 2011, including record cover crops on Maryland farm fields, sewage treatment upgrades that are ahead of schedule (e.g., Blue Plains facility in Washington D.C.), and recovering blue crab populations. Yet the poor scores in Chesapeake Bay health reflect the lag times for restoration efforts to be apparent in Bay health. These report card results also underscore the need for more aggressive and widespread restoration efforts.

Improve water clarity—Live Bay friendly
Water clarity was at an all-time low (5%) in 2011 in Chesapeake Bay. We can improve water clarity, which helps aquatic grasses grow, promotes the right balance of phytoplankton (algae) in the water column, and influences benthic communities (clams and worms living in the sediment) in the following ways:


 Rain barrel



Stop sediment and nutrients from running off
your property into storm drains. Divert rainwater
into rain barrels, rain gardens, and natural areas.
Reduce fertilizer use and re-use materials by
composting.




Rain garden



Support local initiatives that convert hard
surfaces like parking lots into green space like
rain gardens. Report turbid water running off
from public sites, such as construction areas,
to your local government.




Alternative transportation



Use public and alternative transportation
where possible to decrease the particulates
from exhaust that enter waterways. Support
state and federal initiatives for low-impact and
environmentally friendly development. 




Health Index Map

This map shows the Bay Health Index for all reporting regions. You can also access individual reporting region summary pages by clicking on them, or mousing over for quick summaries.

Estuary Selection MapOverall BayLower BayUpper BayYork RiverElizabeth RiverJames RiverRappahannock RiverLower Eastern Shore (Tangier)Mid BayPotomac RiverPatuxent RiverChoptank RiverUpper Eastern ShoreLower Western Shore (MD)Patapsco and Back RiversUpper Western ShoreMid Bay

 

Region Rankings

2011 Bay health declines from 2010
Overall health was worse in 2011 compared to 2010, decreasing from a score of 42% to 38% which is rated a D+, or poor. Overall declines were seen in all three water quality indicators and aquatic grasses in 2011. Phytoplankton community was the only indicator to improve. Overall condition of benthic community across the Bay was about the same in 2011 as in 2010. The decline in 2011 overall Bay health likely reflects a hot dry summer, followed by two major storms (Hurricane Irene and Tropical Storm Lee). These extreme weather events brought high levels of sediments and nutrients to the Bay as well as decreasing water salinity which affected the biotic index.

Only two reporting regions (Lower Western Shore and Patapsco River) had improved grades in 2011, five were unchanged, and eight declined. For the first time the Elizabeth River received a grade this year, an F. The Patuxent River also received a failing grade this year. The highest-ranked region last year, the Upper Bay, remained the best score throughout the bay, although it decreased slightly to a C.

This table shows the Water Quality Index, Biotic Index and the overall Bay Health Index for all reporting regions. Mouseover the index values to see the values of the component indicators/indices. You can also access individual reporting region summary pages by clicking on their name, or indicator details by clicking on their icons.



Score Legend
Upper BayLower BayUpper Western ShoreOverall BayLower Eastern Shore (Tangier)James RiverRappahannock RiverUpper Eastern ShoreMid BayYork RiverLower Western Shore (MD)Potomac RiverChoptank RiverPatapsco and Back RiversPatuxent RiverElizabeth River 
Water Quality IndexChlorophyll a Dissolved Oxygen Water Clarity 48313933394935292834173228152127 
Biotic IndexAquatic Grasses Benthic Index of Biotic Integrity Phytoplankton Index of Biotic Integrity 6165524336263731302238222430160 
Bay Health Index54484538373736302928282726231914 

 

Excel Spreadsheet

Region Summaries

Listed in order of Bay Health Index from best to worst. You can access more detailed information on each reporting region by click on the region names.

Score Legend

RegionScore (%)Comments
Upper Bay
54
C
Moderate ecosystem health-highest ranked region in the Bay. Improvements in chlorophyll a and phytoplankton community scores offset decreases in water clarity and aquatic grass scores.
Lower Bay
48
C
Moderate ecosystem health. Overall health remained the same, with an improved phytoplankton community and moderately decreased water quality scores.
Upper Western Shore
45
C
Moderate ecosystem health—second highest ranked region. While the benthic community score improved, the chlorophyll a and aquatic grass scores declined. Very poor water clarity persists in this region.
Overall Bay
38
D+
Poor ecosystem health. The overall health of the Bay declined for the second year in a row, from 42% in 2010 to 38% in 2011. Five of the six indicators—dissolved oxygen, chlorophyll a, water clarity, aquatic grasses, and benthic community—declined in score, while phytoplankton community scores increased this year.
Lower Eastern Shore (Tangier)
37
D+
Poor ecosystem health. While small improvements occurred in dissolved oxygen and chlorophyll a scores, benthic community declined. This region continues to bounce between C and D grades.
James River
37
D+
Poor ecosystem health. The phytoplankton and benthic communities were notably worse than 2010, bringing the overall grade down from a C in 2010 to a D+ in 2011.
Rappahannock River
36
D+
Poor ecosystem health. Significant declines in the aquatic grasses score changed the overall grade from a C- to a D+. Other indicators showed minimal changes.
Upper Eastern Shore
30
D
Poor ecosystem health. Declines in most of the indicators were offset by strong improvements in the benthic community score. Overall, there was minor improvement since 2010.
Mid Bay
29
D
Poor ecosystem health. With the biggest decline since 2010 (-13%), the Mid Bay health decreased due to considerable declines in chlorophyll a, water clarity, and phytoplankton community scores.
York River
28
D
Poor ecosystem health. While there were decreases in the water clarity, aquatic grasses, and benthic community scores, these changes were minor and the grade remained the same as 2010.
Lower Western Shore (MD)
28
D
Poor ecosystem health. Greatest improvement from 2010 (F to D). Strong scores in phytoplankton and benthic communities offset small declines in dissolved oxygen.
Potomac River
27
D
Poor ecosystem health. Declines in water clarity and benthic community brought down the score slightly, but not enough to change the grade for 2011.*

*The aquatic grass score for this region is an estimate based on partial 2010 and 2011 data.
Choptank River
26
D
Poor ecosystem health. This region had the greatest decrease in water clarity scores, but aquatic grasses and benthic community improved. Overall score remained steady.
Patapsco and Back Rivers
23
D-
Poor ecosystem health. Both phytoplankton and benthic community scores considerably improved compared to 2010, which improved the overall grade to a D-.
Patuxent River
19
F
Very poor ecosystem health. Declines in dissolved oxygen and phytoplankton community brought the overall grade to an F.*

*The aquatic grass score for this region is an estimate based on partial 2010 and 2011 data.
Elizabeth River
14
F
Very poor ecosystem health—lowest ranked region in the Bay. This is the first year where this region has received a grade. Three of the indicators, water clarity, phytoplankton community, and benthic community, each scored a 0%.

Comparison


Comparison of Bay Health Index scores for 2011 () compared to
()


 Score (%)
 0               20               40               60               80              100
  
Upper Bay  
Lower Bay  
Upper Western Shore  
Overall Bay  
Lower Eastern Shore (Tangier)  
James River  
Rappahannock River  
Upper Eastern Shore  
Mid Bay  
York River  
Lower Western Shore (MD)  
Potomac River  
Choptank River  
Patapsco and Back Rivers  
Patuxent River  
Elizabeth River  

Score Legend

Background


Report Card NewsletterPDF Icon
Chesapeake Bay 2007: Land use and the Chesapeake Bay report card
The report card aims to inform citizens on the progress Chesapeake Bay is making toward becoming a healthy ecosystem. This year's report card shows that the health of the Bay improved slightly in 2007 when compared to 2006. While the overall health of the Bay and most regions of the Bay improved, the health of some regions of the Bay declined. This newsletter also explores some of the long-term changes in report card scores, making a connection between the scores and influencing factors such as land use and nutrient loads.

Getting to the source of the problem

It is well understood that excessive nitrogen, phosphorus, and sediments are major causes of Chesapeake Bay's poor health condition. To help reduce the amount of these pollutants entering the Bay, it is important to determine their sources, so that restoration efforts can be targeted for maximum effect. One of the tools used to estimate pollutant sources and loads and the effectiveness of best management practices (BMPs) is the Chesapeake Bay Watershed Model. This model estimates loads for a variety of land use types, based on factors such as BMP assumptions, average hydrology, vegetation cover, and point source nutrient loads. A simple assessment of the modeled nitrogen load estimates illustrates that the largest contributors are the Susquehanna, Potomac, and James Rivers, mainly due to the fact that these rivers have the largest watersheds. The main sources of nitrogen within each of the regions vary significantly. Agriculture is estimated to be the main source of nitrogen in the Eastern Shore regions, while point sources (wastewater) are the main factors in the James River and Patapsco and Back Rivers regions. The different primary nitrogen sources and the Bay health scores highlight the need for targeted implementation of best management practices. While the figure below provides a modeled estimate of nitrogen into each of the report card regions, it does not account for mixing or transport of nutrients from one region (e.g., the mainstem Bay) to another (e.g., a tributary such as the Patuxent River).

Estimated total nitrogen loads for 13 watersheds/regions in the Chesapeake Bay Watershed and the 2007 Bay Health Index for the 15 reporting regions.

Data: The Chesapeake Bay Watershed Model, Phase 4.3, 2007 Progress Run was used to estimate total nitrogen and phosphorus loads to Chesapeake Bay. Estimates for wastewater based on measured discharges; other categories based on average hydrology and current BMP efficiency assumptions. Does not include contributions from direct atmospheric deposition to tidal waters, tidal shoreline erosion, or the ocean.


Linking land use to Bay health

The Bay Health Index (BHI) provides a broad-level approach to assess the connection between land use and Bay condition. Land use within each of the watersheds is compared with the health of the adjacent waterway. In general, the higher the proportion of agricultural and developed land relative to forested land, the lower the BHI. This approach does not account for pollutants from other sources, such as coastal erosion or transport from adjacent waterways, but the strong correlation suggests that watershed activities in each region highly influence the BHI of the corresponding waterway. This relationship provides a useful framework from which the effects of land use change and best management practice (BMP) implementation can be viewed. Theoretically, if land use (% development and agriculture) stays the same, and the implementation of urban and agricultural best management practices is increased, then the health of the Bay will improve. Conversely, if BMPs were to decrease, then we can expect the health of the Bay to deteriorate. Additionally, if BMPs stay the same and land use (area % development and agriculture) changes, then the health of the Bay will also respond. This is an oversimplification of these relationships, but still serves as a good conceptual framework. An example of this oversimplification can be seen when looking at the effects of land use change from agriculture to developed land. Developed land (including urban run-off and partial treatment of human waste) within the Chesapeake watershed generates on average a total of 14.8 pounds of nitrogen per acre compared with the average agricultural rate of 11.71. Based on these numbers, a shift toward developed land at the expense of agricultural land will lead to increased nutrient loads unless urban BMPs can keep up with land use change — a factor not captured by the relationship shown.

The average Bay Health Index decreases with increasing conversion of forested lands to agriculture and urban development.


Estimated total nitrogen loads for 13 watersheds/regions in the Chesapeake Bay Watershed.

Data: Chesapeake Bay Watershed Model, Phase 4.3.


Best Management Practices

There are literally hundreds of Best Management Practices (BMPs) that target reduction of nutrient and sediment loads to Chesapeake Bay. These may be as simple as individuals fertilizing their lawn during the recommended time of the year (fall), to large and expensive engineering exercises such as upgrading municipal wastewater treatment plants. Here are some of the most important and some of the new BMPs being undertaken in agriculture and urban areas.

BMP Conceptual Diagram

Agricultural BMPs

A. Cover crops - Non-harvested cereal cover crop specifically planted in fall for nutrient removal. Cereal cover crops reduce erosion and the leaching of nutrients to groundwater by maintaining a vegetative cover on cropland and holding nutrients within the root zone during the non-growing cash crop season (winter).
B. Riparian buffers - Up to 100-foot-wide buffer of grass, non-woody, or woody (forest) vegetation between crop and waterway. A 100-foot-wide strip of grass buffer can reduce sediment significantly. Fencing to exclude farm animals, although not a riparian buffer, can help slow the erosion of streamside soil.
C. Animal manure management - Animal farming uses directed flows to better contain waste products from animal houses. Lagoons, ponds, steel or concrete tanks, and storage sheds are used for the treatment and/or storage of wastes.

Urban BMPs

D. Septic upgrades - Septic denitrification represents the replacement of traditional septic systems with more advanced systems that have additional nitrogen removal capabilities. Septic connections/hookups represent the replacement of traditional septic systems with connection to and treatment at wastewater treatment plants.
E. Stormwater management control - Includes rain gardens (which direct flow from impervious surfaces to a vegetated area before the water reaches the storm drain), green roofs (which use the rainwater hitting the roof to feed plants), and riparian buffers. Filtering practices capture and temporarily store the water quality volume and pass it through a filter of sand, organic matter, and vegetation, promoting pollutant treatment and recharge.
F. Enhanced nutrient removal - Wastewater treatment plants are being upgraded to enhanced nutrient removal, which uses the most efficient removal process available, before the water is discharged into local waterways.