Impaired Waters and Clean-up Plans

1. Defining Restored Bay Water Qualityfrom the Perspective of Fish, Crabs, Oysters and Underwater Grasses:Chesapeake Bay Dissolved Oxygen, Water Clarity and Chlorophyll a Criteria

2. Impaired Waters and Clean-up Plans Portions of the Chesapeake Bay and its tidal rivers are listed under the Clean Water Act as “impaired waters” largely because of low dissolved oxygen levels and other problems related to nutrient pollution. Impaired Water

3. Chesapeake 2000: The New Agreement In June 2000, the Chesapeake Bay Program partners signed a new agreement to guide the restoration and protection of the Bay through the next decade and beyond. In Chesapeake 2000, the partners agreed that: Improving water quality is the most critical element in the overall protection and restoration of the Chesapeake Bay and its rivers.

4. Chesapeake Bay Watershed Partners • Signatories to the Chesapeake Bay agreement • EPA (representing the Federal government) • Jurisdictions of MD, PA, VA and DC • Chesapeake Bay Commission (representing MD, PA and VA state legislatures) • Headwater states • DE, NY and WV • Memorandum of Understanding linked to water quality goals

5. Chesapeake 2000 AgreementWater Quality Protection and Restoration • Integrate cooperative Chesapeake Bay • Program and statutory Clean Water Act processes. • By 2010, correct the nutrient- and sediment-related • problems in the Chesapeake Bay and its tidal • tributaries and… • Remove the Bay and tidal tributaries from the list • of impaired waters under the Clean Water Act.

6. Chesapeake 2000 AgreementWater Quality Protection and Restoration • Define the water quality conditions necessary to • protect aquatic living resources. • Jurisdictions with tidal waters will use their best • efforts to adopt new or revised water quality • standards consistent with the defined water • quality conditions. • Use the standards as the basis for removing the • Bay and its tidal rivers from the list of impaired • waters.

7. Refined Designated Uses forChesapeake Bay and Tidal Tributary Waters A. Cross Section of Chesapeake Bay or Tidal Tributary Shallow-Water Bay Grass Use Open-Water Fish and Shellfish Use Deep-Water Seasonal Fish and Shellfish Use Deep-Channel Seasonal Refuge Use B. Oblique View of the “Chesapeake Bay” and its Tidal Tributaries Migratory Fish Spawning and Nursery Use Open-Water Habitat Shallow-Water Bay Grass Use Deep-Water Seasonal Fish and Shellfish Use Deep-Channel Seasonal Refuge Use

8. Restored Tidal Water Quality Means: • Fewer algae blooms and better fish food. • Clearer water and more underwater Bay grasses. • More oxygen and improved habitat for more fish, crabs and oysters.

9. Chesapeake Bay Water Quality Criteria • Dissolved Oxygen – for fish, crabs and oysters • Water Clarity – light for underwater Bay grasses • Chlorophyll a – base of the Bay food chain Together, these three criteria define the conditions necessary to protect the wide variety of the Bay’s living resources and their habitats.

10. Chesapeake Bay Criteria Needed for Protection of the Refined Tidal Waters Designated Uses Dissolved Oxygen Chlorophyll a Water Clarity Migratory Spawning and Nursery  Shallow Water   Open Water   Deep Water  Deep Channel 

11. Dissolved Oxygen • Living things--even those underwater--need oxygen! • The amount of oxygen needed in the water depends on the specific needs of the Bay’s living resources. • The amounts depend on where and when certain areas are used by different living resources.

12. Oxygen Requirements (mg/L) of Bay Species Migratory Fish Spawning & Nursery Areas 6 Striped Bass: 5-6 American Shad: 5 Shallow and Open Water Areas 5 White Perch: 5 Yellow Perch: 5 4 Hard Clams: 5 Deep Water Alewife: 3.6 3 Bay Anchovy: 3 Crabs: 3 2 1 Spot: 2 Deep Channel Worms: 1 0

13. Basis for Bay Dissolved Oxygen Criteria • 1992 Chesapeake Bay oxygen restoration goal laid basic foundation • 2000 EPA marine and 1985 EPA freshwater dissolved oxygen criteria documents • Addition of more Bay species effects data • Application of larval recruitment model using Bay specific parameters, species • Authored by a team of Bay region scientists, state agency and federal agency technical staff

14. Oxygen Criteria Derivation for Shallow/Open Water Designated Use

15. Chesapeake Bay Dissolved Oxygen Criteria 1. At temperatures >29oC, dissolved oxygen concentrations above instantaneous minimum of 4.3 mg/L will protect shortnose sturgeon.

16. Water Clarity • All plants--even those underwater--need light! • Water clarity is a measure of the amount of sunlight that penetrates the Bay’s waters and reaches the surface of underwater Bay grass leaves. • The amount needed is determined by the specific underwater grasses which grow in different areas of the Bay.

17. What’s Blocking the Light? Good Water Clarity Poor Water Clarity • Percent of sunlight at the water surface that penetrates the water: • 13% in low salinity waters • 22% in high salinity waters Sediment and other particles in the water + Algae in the water + Algae on the leaves equals Very low percentage of sunlight reaching leaves – Bay grasses grow poorly or die.

18. Basis for Bay Water Clarity Criteria • Two past technical syntheses (1992, 2000) of Chesapeake Bay underwater grasses habitat requirements • Focus on light available to the underwater grasses at the leaf surface • 18 year+ tidal WQ monitoring database • Investments in ecosystem processes modeling

19. “Percent Light” Parameters for Evaluating Ambient Conditions

20. Percent Surface Light Low Salinity Habitats 13% High Salinity Habitats 22% Chesapeake Bay Water Clarity Criteria • The criteria apply to Chesapeake Bay Program segment-specific depths up to two meters. • Areas where underwater bay grasses never occurred or where natural factors, such as currents and wave action, prevent its growth are excluded. • Water clarity criteria only apply to shallow-water bay grass designated use.

21. Watershed partners have adopted a new 185,000 acre Bay grasses restoration goal Water clarity criteria apply in the shallow water habitats at depths needed to restore grasses to these areas. New Bay Grasses Restoration Goal Baltimore Washington DC Cambridge Fredericksburg Richmond Norfolk

22. Chesapeake Bay Water Clarity Criteria for Application to Shallow-Water Bay Grass Designated Use Habitats Example: If a state chooses to use Secchi depth for criteria application at 1.5 meter depth, the criteria equivalent to 13% and 22% PLW is 1.1 and 1.4 meters, respectively.

23. Chlorophyll a • Chlorophyll a is a measure of the amount of algae in the water. • Some algae are good sources of fish food and others are poor sources. • Excessive nutrients can stimulate nuisance algae blooms resulting in reduced water clarity, reduced amounts of “good fish food”, and depleted oxygen levels in deeper waters.

24. Chlorophyll a Criteria Components • Based on fish food/algal composition quantification across an array of poor to good water quality conditions • Narrative criteria to protect against adverse algal-related impacts on water quality • Chlorophyll a concentrations characteristic of a range of water quality conditions and protective against specific water quality impairments have been published • Concentration are applied as: • Salinity regime based • Spring, summer medians

25. Chesapeake BayNarrativeCriteria forChlorophyll a “Concentrations of chlorophyll a in free-floating aquatic plants (algae) shall not exceed levels that result in ecologically undesirable consequences – such as reduced water clarity, low dissolved oxygen, food supply imbalances, proliferation of species deemed potentially harmful to aquatic life or humans or aesthetically objectionable conditions – or otherwise render tidal waters unsuitable for designated uses.” Source: U.S. EPA. 2003.

26. Chesapeake Bay Criteria Guidance for Chlorophyll a Criteria “EPA expects states to adopt narrative chlorophyll a criteria into their water quality standards for all Chesapeake Bay and tidal tributary waters. EPA strongly encourages states to develop and adopt site-specific numerical chlorophyll a criteria for tidal waters where algal-related impairments are expected to to persist even after the Chesapeake Bay dissolved oxygen and water clarity criteria have been attained.” Source: U.S. EPA. 2003.

27. Chlorophyll a Criteria: Supporting Technical Information • Based on fish food/algal composition quantification across an array of poor to good water quality conditions • Phytoplankton growth limiting water quality conditions and and related chlorophyll a concentrations • Concentration characteristic of potentially harmful algal blooms • Concentrations characteristic of trophic-base conditions • Concentrations protective against water quality impairments (water clarity, dissolved oxygen, • Methodologies for deriving water body specific chlorophyll a criteria • Salinity regime based, focused on spring, summer medians with maximum concentrations addressing algal blooms

28. Illustration of Chlorophyll a, Food Quality, and Water Quality Relationships Scientist’s View Chlorophyll Concentration Biomass of Edible Phytoplankton Biomass of Inedible Phytoplankton Water Quality Worst Poor Better Best Restored Poor Water Clarity Excess Nutrients Good Water Clarity Low Nutrients Corresponding Phytoplankton Food Value Poor Good

29. Illustration of Chlorophyll a, Food Quality, and Water Quality Relationships Simplified View Oprah’s Tasty Diet Quantity of Food Available to be Eaten Index Too Much Green Stuff Right Green Stuff for Fish Food Filet Mignon (or Fresh Caesar Salad) with a 1952 French Bordeaux wine McDonald’s Cheeseburgers (and lots and lots of them) Water Quality Worst Poor Better Best Restored Poor Water Clarity Excess Nutrients Good Water Clarity Low Nutrients Corresponding Phytoplankton Food Value Poor Good

30. Illustration of Chlorophyll a, Food Quality, and Water Quality Relationships Simplified View Where the Bay and rivers are now Where the Bay and rivers will be when chlorophyll a criteria are met Water Quality Worst Poor Better Best Restored Poor Water Clarity Excess Nutrients Good Water Clarity Low Nutrients Corresponding Phytoplankton Food Value Poor Good

31. Application of NumericalChlorophyll a Criteria • The narrative criteria describes the various possible impacts on tidal Bay habitats due to too much algae and the wrong types of algae. • Supporting target concentrations will be used by the states to establish numerical chlorophyll a criteria to address localized algal-related problems which are expected to persist even after the Chesapeake Bay dissolved oxygen and water clarity criteria have been attained.

32. Chesapeake Bay Water Quality Criteria

33. Criteria Implementation Procedures A detailed set of criteria implementation procedures have been developed addressing: • Magnitude • Duration • Frequency • Space • Time For determining criteria attainment.

34. Proposed Approach for Defining Attainment • Develop an analytical tool that uses available data to account for spatial and temporal variability in criteria exceedence. • Develop Cumulative Frequency Diagram (CFD). • Develop a precise rule for deciding if a given segment is attaining its designated use.

35. Steps for Developing a CFD Step 1: Interpolate the Bay water quality monitoring data for each sampling event (e.g., cruise)  Station

36. Step 2. Evaluate interpolated WQ monitoring data interpolator cell by cell using the appropriate criterion value Criterion by Salinity

37. Step 3. Identify the cells in a CBP segment / designated use area that exceed the criteria for each sampling event

38. Step 4. Repeat Step 3 for each sampling event in assessment period ... March 1999 April 1999 May 1999 June 1999 March 2000 Apr 2000 May 2000 Assessment Period

39. Step 4. …to generate an event by event accounting of %area (%volume) of a segment exceeding the criteria March 1999 April 1999 May 1999 June 1999 March 2000 Apr 2000 May 2000 Assessment Period

40. Step 5. Compile the measures of % area (%volume) exceeding the criteria. This quantifies the SPATIAL EXTENTof the exceedences in a segment for each sampling event. % Area (%Volume) Exceeding Example Assessment Over A Three Year Assessment Period Month

41. Step 6. Sort and rank the measures of % area/volume of criteria exceedence… % Area (%Volume) Exceeding Month Example Assessment Over A Three Year Assessment Period Rank

42. Step 6. … and calculate the cumulative probability values based on the ranks % Area (%Volume) Exceeding Cumulative Probability (Rank/n+1) Month Rank

43. Step 7. Plot the % area in exceedence vs. cumulative probability over time Example Assessment Over A Three Year Assessment Period April 2000 X=39%, Y=62% %Time the Given % Area/ Volume is in exceedence May 1998 X = 65%, Y = 31% % Area/Volume in Exceedence

44. Step 7. Plot the % area in exceedence vs. cumulative probability over time Example Assessment Over A Three Year Assessment Period at least 39% of the area exceeds the criteria in 62% of the sampling events during the three year assessment period %Time the Given % Area/ Volume is in exceedence at least 65% of the area exceeds the criteria in 31% of the sampling events during the three year assessment period % Area/Volume in Exceedence

45. 100 Percent of Time 90 80 70 60 50 40 30 20 10 0 10 20 30 40 50 60 70 80 90 100 Percent of Space Definition of Criteria Attainment CFD Curve Biologically-Based Reference Curve 0

46. 100 Percent of Time 90 80 70 60 50 40 30 20 10 0 10 20 30 40 50 60 70 80 90 100 Percent of Space Definition of Criteria Attainment Area of Criteria Exceedence Area of Allowable Criteria Exceedence 0

47. More Information is Available The following products are available athttp://www.chesapeakebay.net/baycriteria.htm • Ambient Water Quality Criteria for Dissolved Oxygen, Water Clarity and Chlorophyll a for the Chesapeake Bay and its Tidal Tributaries (U.S. EPA 2003) • Bay specific dissolved oxygen, chlorophyll a, and water clarity criteria published as EPA regional water quality criteria • Baywide implementation guidelines for each of the three criteria

48. More Information is Available The following products are available athttp://www.chesapeakebay.net/uaasupport.htm • Technical Support Document for the Identification of Chesapeake Bay Designated Uses and Attainability (U.S. EPA 2003) • Technical support document providing extensive information on attainability of current and refined tidal water designated uses • Detailed documentation on refined tidal designated uses and recommended use boundaries