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Technical Support Document for Identifying Chesapeake Bay Designated Uses and Attainability
In May 2003, the EPA Region III issued guidance entitled Ambient Water
Quality Criteria for Dissolved Oxygen, Water Clarity and Chlorophyll a
for the Chesapeake Bay and Its Tidal Tributaries (Regional
Criteria Guidance). The development of the Regional Criteria Guidance
was the realization of a key commitment in the Chesapeake
2000 agreement. 
In that agreement, the signatories (the states of Pennsylvania, Maryland
and Virginia; the District of Columbia; the Chesapeake Bay Commission
and the EPA) committed to, "by 2001, define the water quality conditions
necessary to protect aquatic living resources." New York, Delaware
and West Virginia agreed to the same commitment through a separate six-state
memorandum of understanding
[PDF, 2 pages, 94K, about pdf] with the EPA.
In the Regional Criteria Guidance, the EPA has defined the water quality
conditions called for in the Chesapeake 2000 agreement through the development
of Chesapeake Bay-specific water quality criteria for dissolved oxygen,
water clarity
and chlorophyll a.
The EPA also has identified and described five habitats (or designated
uses)
that provide the context in which EPA Region III derived adequately protective
Chesapeake Bay water quality criteria for dissolved oxygen, water clarity
and chlorophyll a. Collectively, the three water quality conditions provide
the best and most direct measures of the effects of too much nutrient
and sediment pollution on the Bay's aquatic living resources-fish, crabs,
oysters, their prey species and underwater bay grasses. These criteria
are being developed as part of a larger effort to restore Chesapeake
Bay water quality.
The Technical Support Document for the Identification of Chesapeake Bay Designated Uses and Attainability (Technical Support Document), below, describes the development and geographical extent of the designated uses to which the criteria may apply. The EPA developed the Technical Support Document to assist states in the development and adoption of refined water quality standards to address nutrient and sediment-based pollution in the Chesapeake Bay and its tidal tributaries. Specifically, the EPA developed the Technical Support Document to help states in conducting use attainability analyses UAA) which states may conduct as part of their water quality standards development and adoption processes.
Previous drafts of the Technical Support Document had been made available
for public review in late 2002. The EPA has compiled all comments received
and is preparing responses to the individual comments submitted. The compilation
of these comments and the EPA's responses will be available in August
2003.
The following are PDF files [about pdf].
Executive Summary:
Cover Page [1 page,17K]
Title Page [1 page, (49K]
Foreword [2 pages, 80K]
Executive Summary [12 pages, 184K]
Table of Contents [4 pages, 107K]
Text:
Chapter I: Introduction [13 pages, 255K]
Chapter II: The Chesapeake Bay and its Watershed [29 pages, 393K]
Chapter III: Why Attaining the Current Tidal-Water Designed Uses Appears Not to be Feasible [20 pages, 193K]
Chapter IV: Refined Designated Uses for the Chesapeake Bay and Its Tidal Tributaries [95 pages, 1.5M]
Chapter V: Technological Attainability of the Refined Recommended Designated Uses a criteria [30 pages, 251K]
Glossary [9 pages, 132K]
Acronyms [2 pages, 55K]
Appendices:
Appendix A: Development of the Level-of-Effort Tiers [47 pages, 107K]
Appendix B: Data Supporting Determination of the Shallow-Water Designated Use Depths and Underwater Bay Grasses Restoration Goals [11 pages, 162K]
Appendix C: Underwater Bay Grasses No-Grow Zones [2 pages, 102K]
Appendix D: Vertical Stratification and the Pycnoclines [10 pages, 166K]