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Water Quality Standards Achievement

Results for 2010-2012 indicated that 31* percent of the Chesapeake Bay was attaining water quality standards for dissolved oxygen, water clarity/underwater bay grasses and chlorophyll a.




Chesapeake Bay Waters Meeting WQ Goals for Open Water, Deep Water, and Deep Channel Uses 2010-2012

Map: Chesapeake Bay Waters Meeting WQ Goals for Open Water, Deep Water, and Deep Channel Uses 2010-2012

Date created: Nov 06 2013 / Download

This map demonstrates the attainment status of those Chesapeake Bay Program monitoring segments that have dissolved oxygen standards for the Open Water, Deep Water, and Deep Channel designated use during the 2010-2012 assessment period.


Chesapeake Bay Waters Meeting WQ Goals for the Migratory, Spawning and Nursery Habitat Use 2010-2012

Map: Chesapeake Bay Waters Meeting WQ Goals for the Migratory, Spawning and Nursery Habitat Use 2010-2012

Date created: Nov 06 2013 / Download

This map demonstrates the attainment status of those Chesapeake Bay Program monitoring segments that have dissolved oxygen standards for the Migratory, Spawning and Nursery Habitat designated use during the 2010-2012 assessment period.


Chesapeake Bay Waters Meeting WQ Goals for the Shallow Water Bay Grasses Designated Use 2010-2012

Map: Chesapeake Bay Waters Meeting WQ Goals for the Shallow Water Bay Grasses Designated Use 2010-2012

Date created: Nov 06 2013 / Download

This map demonstrates the attainment status of those Chesapeake Bay Program monitoring segments that have SAV and/or water clarity standards for the Shallow Water Bay Grasses designated use during the 2010-2012 assessment period.


Chesapeake Bay Waters Meeting Chlorophyll a Criteria Water Quality Goals 2010-2012

Map: Chesapeake Bay Waters Meeting Chlorophyll a Criteria Water Quality Goals 2010-2012

Date created: Nov 06 2013 / Download

This map demonstrates the attainment status of those Chesapeake Bay Program monitoring segments that have numeric chlorophyll a standards for the Open Water designated use during the 2010-2012 assessment period.




September 03, 2013

What is dissolved oxygen? Laura Fabian from the Maryland Department of Natural Resources (DNR) explains why oxygen is so important to underwater life and how it is used to measure water quality in the Chesapeake Bay.

Produced by Matt Rath
Music: “A Moment of Jazz” by Ancelin



September 03, 2013

Bay grasses, also known as submerged aquatic vegetation, are an integral part of the Chesapeake Bay ecosystem. Lee Karrh from the Maryland Department of Natural Resources (DNR) explains what bay grasses need to grow and why their survival is important to Bay critters.

Produced by Matt Rath
Music: “A Moment of Jazz” by Ancelin



September 03, 2013

Clear water is critical to underwater life. Bay grasses need sunlight to grow, and fish need sunlight to see. But what factors cause water clarity to fluctuate? Adam Davis from the Chesapeake Research Consortium explains, and uses a secchi disc to measure water clarity in Spa Creek.

Produced by Matt Rath
Music: “A Moment of Jazz” by Ancelin



September 03, 2013

What is an algae bloom and how does it form? Charlie Poukish from the Maryland Department of the Environment explains what fuels algae blooms and how they can spell trouble for underwater life.

Importance

This indicator measures progress towards the achievement of water quality standards for dissolved oxygen, water clarity/underwater bay grasses and chlorophyll a for each 3-year assessment period beginning in 1985.  The indicator is fully consistent with how Delaware, the District of Columbia, Maryland, and Virginia currently list their portion of the Bay’s tidal waters, and provides a means for illustrating improvements through time. Additionally, this indicator is being used to measure progress toward the Chesapeake Bay Executive Order Strategy’s water quality outcome.

Long-term Trend (1985-2012)

A straight line trend analysis shows there has been a positive, improving trend in the amount of the Bay’s tidal waters achieving water quality standards over the 1985 to 2012 time period*.

Short-term Trend (2002-2012)
A straight line trend analysis shows there has been no significant trend in the amount of the Bay’s tidal waters achieving water quality standards over the 2002 to 2012 time period*.

Change from Previous Year

Results for 2010-2012 indicated that 31* percent of the Bay was attaining water quality standards. These results are not significantly different from those of the previous assessment year (2009-2011) in which 30 percent of the Bay was attaining water quality standards.

Additional Information

* Based on best available data, not including water clarity assessment results from Maryland.  The percentage may change after water clarity assessment data for 2010-2012 assessment period become available from Maryland and are incorporated into the calculations.  At that time the 2010-2012 status will be revised if necessary.

Nutrients, along with sediments, are the primary causes of impairments to the Chesapeake Bay and its tidal tributaries. To meet the objectives of the Clean Water Act, the EPA’s implementing regulations specify that states must adopt criteria that contain sufficient parameters to protect existing and designated uses. In 2003, EPA Region III developed Ambient Water Quality Criteria for Dissolved Oxygen, Water Clarity, and Chlorophyll a for the Chesapeake Bay and Its Tidal Tributaries. This was developed in order to achieve and maintain water quality conditions necessary to protect the aquatic living resources of the Chesapeake Bay and its tidal tributaries from the effects of nutrient and sediment pollution. Within the publication, five designated uses were identified and described, that when adequately protected, will ensure the protection of the living resources therein.

The methodology used for the calculation of the indicator considers the achievement or non-achievement of the dissolved oxygen, water clarity/underwater bay grasses, and chlorophyll a water quality standards applicable to a designated use within a segment. Rather than reporting progress only when all designated uses are met within a segment, this methodology reports when a water quality standard is met for each of the designated uses in that segment; therefore, rather than reporting on the 92 Chesapeake Bay segments used for the establishment and management of the Chesapeake Bay Total Maximum Daily Load (TMDL), this methodology reports on 291 designated-use segments contained within.

This indicator uses a surface area-weighted approach, which multiplies the surface area of each of the 92 segments times the number of applicable designated uses and criteria for that segment. This approach factors in the relative size of each segment, ensuring we report the best available measure of how much of the Bay tidal waters were achieving water quality standards. At the same time, this approach gives equal weight to achievement of the criteria protective of each designated use and segment, preventing any need to weigh differently the importance of restoring dissolved oxygen versus bringing back underwater bay grasses. Restoration of a fully functioning Chesapeake Bay ecosystem requires attainment of all five designated uses and their applicable criteria. This indicator consolidates the baywide results in the final calculations and reports percent of Bay water quality standards in attainment.

Source of Data

Chesapeake Bay Program

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