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Defining Restored Bay and Tidal Tributary Water Quality  Round Two  Draft Revised Oxygen, Water Clarity and Chlorophyll Criteria.

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Presentation on theme: "Defining Restored Bay and Tidal Tributary Water Quality  Round Two  Draft Revised Oxygen, Water Clarity and Chlorophyll Criteria."— Presentation transcript:

1 Defining Restored Bay and Tidal Tributary Water Quality  Round Two  Draft Revised Oxygen, Water Clarity and Chlorophyll Criteria


3 Refined Designated Uses for Chesapeake Bay and Tidal Tributary Waters A. Cross Section of Chesapeake Bay or Tidal Tributary B. Oblique View of the “Chesapeake Bay” and its Tidal Tributaries Shallow Water Open Water Deep Water Deep Channel Open Water Habitat Shallow Water Habitat Deep WaterDeep Channel Migratory Finfish Spawning and Nursery Habitat

4 Refined Designated Uses Migratory Spawning & Nursery Waters:  tidal freshwater to low salinity habitats in the upper reaches of many Bay tributaries, Susquehanna flats, and upper main Bay  supports a wide array of migratory fish during late winter to spring spawning season  “Fish Spawning Habitat” Shallow Water:  nearshore habitat; primary focus on underwater grasses  supports a wide variety of fish and crabs  “Bay Grass Habitat”

5 Refined Designated Uses (continued) Open Water:  surface water habitats, extending from shallow shoreline areas across tidal rivers and main Bay  supports diverse populations of sportfish and baitfish  “Finfish Habitat” Deep Water:  transitional water column habitat between well mixed surface waters and very deep, narrower channels  supports fish like bay anchovy as well as many bottom feeding fish, crabs and other shellfish  “Shellfish Habitat”

6 Refined Designated Uses (continued) Deep Channel:  very deep channel habitats  low dissolved oxygen levels prevail during summer months  important summer location of food for bottom feeding fish and crabs; winter refuge habitat for many fish species  includes seasonal anoxic “exclusion” zones, where natural conditions cause complete lack of dissolved oxygen  “Seasonal Refuge Habitat”

7 Migratory Spawning and Nursery Habitat Spawning and Nursery Habitat Source: Funderburk et al. 1992. Habitat Requirements for Chesapeake Bay Living Resources Revised Edition. Chesapeake Bay Program, Annapolis, MD.

8 Water Quality Criteria Dissolved Oxygen - necessary for all aquatic living resources Water Clarity - key factor for underwater grass growth/survival Chlorophyll - indicates algae levels, “fish food” value, and overall water quality

9 Draft Bay Dissolved Oxygen Criteria Minimum Amount of Oxygen (mg/L) Needed to Survive by Species Hard Clams: 5 Striped Bass: 5-6 Worms: 1 Migratory Spawning & Nursery Areas 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

10 Summer Dissolved Oxygen

11 Draft Dissolved Oxygen Criteria Deeper waters allowed lower DO levels during summer Current Draft Tidal Water Designated Uses

12 Draft Bay Water Clarity Criteria Good Water Clarity Poor Water Clarity Algae in the water Sediment and other particles in the water Algae on the leaves Percent of sunlight reaching leaves: 9% in low salinity waters 15% in high salinity waters + + equals Very low percentage of sunlight reaching leaves – Bay grasses grow poorly or die. Percent of sunlight through water: 13% in low salinity waters 22% in high salinity waters

13 Water Quality Worst Best Poor Water Clarity Excess Nutrients Good Water Clarity Low Nutrients Corresponding Fish Food Value PoorGood Bay Chlorophyll Criteria Based on Restoring Good Fish Food Bay Chlorophyll Criteria Where the Bay and rivers are now Too Much of the Wrong Green Stuff Right Green Stuff for Fish Food

14 Comparing Draft Chlorophyll Criteria with Monitoring Data Draft Criteria (ug/l):

15 * Deep Channel * Deep Water ** Open Water ** Shallow Water * Migratory Spawning and Nursery Water ClarityChlorophyllDissolved Oxygen Chesapeake Bay Criteria Needed for Protection of the Proposed Tidal Waters Designated Uses

16 Bay Criteria Schedule July-Sept 2001 - first round of CBP partners review May-July 2002 - second round of CBP partners/ stakeholders review; independent peer review Oct-Nov 2002 - third round of review Jan 2003 - EPA publication of Bay criteria 2003/2004 - State adoption (MD, VA, DE, DC) of Bay criteria, refined uses as WQ standards

17 Final Products Bay-specific oxygen, chlorophyll, and clarity criteria published as EPA regional water quality criteria Baywide guidelines for application defining attainment of each of the three criteria Consistent tidal designated uses across states published as part of the criteria document

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