1. Chesapeake Bay Hypoxia: History and Management Response Rich Batiuk Associate Director for Science Chesapeake Bay Program Office U.S. Environmental Protection Agency Rob Magnien NOAA Center for Sponsored Coastal Ocean Research

4. 1949- 1950 1957- 1950 1960- 1963 1967- 1968 1972 1978- 1980 June 1984-December 2003 1952 Chesapeake Bay Summer Anoxic/Hypoxic Volumes and Winter-Spring Flow: 1949-2003 Source: www.chesapeakebay.net

5. Source: Hagy et al. 2004 Calculated Summer Anoxic/Hypoxic Volumes and Model Predictions: 1950-2001

6. Summer dissolved oxygen profiles in Chesapeake Bay: Four years with near average January–May Susquehanna River flow Source: Hagy et al. 2004 Extent of Anoxic Conditions

7. January February March April May Early June Late June Early July Late July Early August Late August September October November December A Year in Chesapeake Bay Dissolved Oxygen: 2004

8. 2006 Summer Chesapeake Bay Dissolved Oxygen

9. 2006 Chesapeake Bay Mainstem Anoxic Volume Forecast Red zone indicates forecast area Forecast Volume Observed Volume 95% Confidence Interval Source: www.chesapeakebay.net/bayforecastspring2006.htm Algal index = spring Susq. TN, TP + N. Bay PS TN, TP

10. Impaired Water Over 90% of the Bay and its tidal rivers are impaired due to low dissolved oxygen levels and poor water clarity, all related to nutrient and sediment pollution. Source: U.S. EPA

11. Partners Commitment to Restored Bay Water Quality “By 2010, correct the nutrient ‑ and sediment ‑ related problems in the Chesapeake Bay and its tidal tributaries...” Step 1: What is the water quality of a restored Bay? Step 2: How much pollution do we need to reduce? Step 3: What actions do we need to take to reduce pollution? Source: Chesapeake Executive Council 2000

12. What Do We Want to Achieve? Water quality that supports abundant fish, crabs, oysters and underwater grasses in the Bay and its rivers. Source: Chesapeake Executive Council 2000

13. Water Quality in a Restored Bay 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. Source: U.S. EPA 2003a

14. A. Cross Section of Chesapeake Bay or Tidal Tributary B. Oblique View of the “Chesapeake Bay” and its Tidal Tributaries Shallow-Water Bay Grass Use Open-Water Fish and Shellfish Use Deep-Water Seasonal Fish and Shellfish Use Deep-Channel Seasonal Refuge Use Open-Water Habitat Migratory Fish Spawning and Nursery Use Refined Designated Uses for the Bay and Tidal Tributary Waters Shallow-Water Bay Grass Use Deep-Water Seasonal Fish and Shellfish Use Deep-Channel Seasonal Refuge Use Source: U.S. EPA 2003b

15. Bay Dissolved Oxygen Criteria Minimum Amount of Oxygen (mg/L) Needed to Survive by Species Migratory Fish Spawning & Nursery Areas Hard Clams: 5 Striped Bass: 5-6 Worms: 1 Shallow and Open Water Areas Deep Water Deep Channel 6 5 3 2 1 4 0 Crabs: 3 Spot: 2 White Perch: 5 American Shad: 5 Yellow Perch: 5 Alewife: 3.6 Bay Anchovy: 3 Source: U.S. EPA 2003a

16. Chesapeake Bay Dissolved Oxygen Criteria Designated UseCriteria Concentration/DurationProtection ProvidedTemporal Application Migratory fish spawning and nursery use 7-day mean > 6 mg liter -1 (tidal habitats with 0-0.5 ppt salinity) Survival/growth of larval/juvenile tidal-fresh resident fish.; protective of threatened/endangered species. February 1 - May 31 Instantaneous minimum > 5 mg liter -1 Survival and growth of larval/juvenile migratory fish; protective of threatened/endangered species. Open-water fish and shellfish designated use criteria applyJune 1 - January 31 Shallow-water bay grass use Open-water fish and shellfish designated use criteria applyYear-round Open-water fish and shellfish use 30-day mean > 5.5 mg liter -1 (tidal habitats with 0-0.5 ppt salinity) Growth of tidal-fresh juvenile and adult fish; protective of threatened/endangered species. Year-round 30-day mean > 5 mg liter -1 (tidal habitats with >0.5 ppt salinity) Growth of larval, juvenile and adult fish and shellfish; protective of threatened/endangered species. 7-day mean > 4 mg liter -1 Survival of open-water fish larvae. Instantaneous minimum > 3.2 mg liter -1 Survival of threatened/endangered sturgeon species. 1 Deep-water seasonal fish and shellfish use 30-day mean > 3 mg liter -1 Survival and recruitment of bay anchovy eggs and larvae. June 1 - September 30 1-day mean > 2.3 mg liter -1 Survival of open-water juvenile and adult fish. Instantaneous minimum > 1.7 mg liter -1 Survival of bay anchovy eggs and larvae. Open-water fish and shellfish designated-use criteria applyOctober 1 - May 31 Deep-channel seasonal refuge use Instantaneous minimum > 1 mg liter -1 Survival of bottom-dwelling worms and clams.June 1 - September 30 Open-water fish and shellfish designated use criteria applyOctober 1 - May 31 1 At temperatures considered stressful to shortnose sturgeon (>29 E C), dissolved oxygen concentrations above an instantaneous minimum of 4.3 mg liter -1 will protect survival of this listed sturgeon species.

18. Scientific Basis for Decisions was Documented by the Partners

19. Bay Criteria, Uses Adopted in State WQS Regulations DE (2004), MD (2005), VA 2005/2006), DC (2006) Standards adopted in terms of designated use by CBP segment WQ criteria, uses, attainment assessment methods essentially fully consistent across jurisdictions

20. Chesapeake Bay Program Models Chesapeake Bay Watershed Model Chesapeake Bay Airshed Model Chesapeake Bay Water Quality Model SAV/Light Model Hydrodynamic Model Sediment Transport Model Benthic Infauna Model Zooplankton Model Oyster Filter Feeders Model Sediment Process Model Phytoplankton Model

21. Chesapeake Bay Program Current Modeling Structure Airshed Model Watershed Model Estuary Model

22. Nutrient Loadings vs. Dissolved Oxygen Criteria Attainment % Dissolved Oxygen Criteria Attainment Millions of pounds per year nitrogen phosphorus 337 285 175 26.5 19.1 12.8

23. Nutrient pollution loads have differing impacts on the Bay water quality, depending on where they come from.

24. Watershed States Responsibility Allocating Responsibility for Reducing Nutrients and Sediments By 9 major river basins...then by 20 major tributary basins by jurisdiction …then by 44 state- defined tributary strategy subbasins Watershed Partners Responsibility Watershed States Responsibility

25. Nutrient and Sediment Cap Load Allocations -Science-based -Equitable - Based on pollution contribution to Bay/river water quality -Adopted by the six watershed states’ Governors, the DC Mayor and EPA Adminstrator in 2003

26. Unprecedented multi-state permitting agreement Annual load limits vs. monthly conc. limits Watershed-based permitting Addresses complex compliance schedule issues Addresses monitoring requirements and reporting schedules Basinwide Permitting Approach

28. Nitrate and ammonia deposition from improved Daily Nitrate and Ammonium Concentration Models using 35 monitoring stations over 18 simulation years. Adjustments to deposition from Models-3/Community Multi-scale Air Quality (CMAQ) Modeling System Phase 5 Watershed Model Year-to-year changes in land use and BMPs; 899 segments; 24 land uses; 296 calibration stations; 21 simulation years; sophisticated calibration procedures; calibration demonstrably better in quality and scale Chesapeake Bay Estuary Model Detailed sediment input; Wave model for resuspension, Full sediment transport; Filter feeder simulation; Simulation of Potomac algal blooms; 54,000 model cells; 18 simulation years The Forthcoming Next Generation of Bay Models

29. Less Than Third of the Bay Has Enough Oxygen

30. Rich Batiuk Associate Director for Science U.S. Environmental Protection Agency Chesapeake Bay Program Office 410-267-5731 batiuk.richard@epa.gov www.chesapeakebay.net