Technical Support Fact Sheet Guiding Chesapeake Bay Water Quality Restoration: The Use Attainability Analysis Technical Support Document and Economic Analyses Document

Technical Support Fact Sheet
410 Severn Avenue, Suite 109
Chesapeake Bay Program Annapolis, Maryland 21403
a watershed Partnership voice 410-267-5700 • toll free 800-YQUR-BAY • www.chesapeakebay.net
10/2003
Guiding Chesapeake Bay Water Quality Restoration:
The Use Attainability Analysis Technical Support Document and Economic
Analyses Document
The most recent Chesapeake Bay protection and restoration agreement-Chesapeake 2000-calls for Chesapeake
Bay Program partners to achieve and maintain the water quality necessary to support the aquatic resources of the
Bay and its tidal tributaries and to protect human health. To achieve these objectives, the U.S. Environmental
Protection Agency (EPA), in close collaboration with its watershed partners-the states of Maryland, Virginia,
Pennsylvania, New York, Delaware and West Virginia and the District of Columbia-published new Chesapeake Bay
regional water quality criteria for dissolved oxygen, water clarity and chlorophyll a in April 2003.
These new water quality criteria are the building blocks for improving water quality for the plants and animals that
live in the Chesapeake Bay. By 2005, Maryland, Virginia, Delaware and the District of Columbia will develop and
adopt new state water quality standards that reflect the newly established water quality criteria. Part of the
development and adoption of new standards will entail revising current underlying tidal-water designated uses in
these jurisdictions. Current designated uses applied to the waters of the
Chesapeake Bay and its tidal tributaries do not fully reflect natural conditions and
are too broad in their definition of 'use' to support the adoption of more habitat-
specific aquatic life criteria.
The Use Attainability Analysis
As part of their water quality standards development process, the states and the
District of Columbia will conduct use attainability analyses (UAA). A UAA is a
scientific study to assess the factors affecting the attainment of a use. The
factors may be of a physical, chemical biological and/or economic nature. The
federal water quality standards regulation requires states to undertake UAAs to
remove or establish a subcategory of a designated use that requires less
stringent water quality criteria. The evaluations conducted in a UAA determine
the attainable uses for a water body.
The Technical Support Document
While a Use Attainability Analysis is conducted by a state in the course of
adopting new or revised water quality standards, the Chesapeake Bay Program
developed information on a watershed-wide scale to promote coordination and
consistency across all jurisdictions during the UAA processes.
The document containing this information is entitled the Technical Support
Document for Identification of Chesapeake Bay Designated Uses and Attainability
(Technical Support Document). The Technical Support Document is not a
regulation or a mandatory requirement; it is a guidance and technical document
cooperatively developed by all Chesapeake Bay jurisdictions. Throughout each
jurisdiction's water quality standards development process, further jurisdiction-
specific analyses may be conducted to supplement basin-wide information.
Key Terms
A designated use is an
element of a water quality
standard, expressed as a
narrative statement, describing
an appropriate intended human
and/or aquatic life objective for
a water body. Designated uses
for a water body may include:
recreation, shellfishing, water
supply and/or aquatic life
habitat.
Water quality criteria are part
of a water quality standard, and
may be numeric or narrative.
Criteria represent a quality of
water that supports a particular
designated use. When criteria
are met, water quality will
generally protect the use.
Water quality standards are a
provision of State or Federal
law consisting of a designated
use or uses for a water body
and the quantifiable criteria
protective of the use(s).
Standards may be annual or
seasonal, depending on the
designated use.
The Chesapeake Bay Program is restoring the Bay through a partnership among the U.S. Environmental Protection Agency representing the federal
government, the State of Maryland, the Commonwealth of Pennsylvania, the Commonwealth of Virginia, the District of Columbia, the Chesapeake Bay
Commission, and participating citizen advisory groups.

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The Use Attainability Analysis Technical Support Document and Economic Analyses Document
Page 2
Designated Use Development
The Technical Support Document provides guidance for revising current designated uses, as well as for setting
appropriate new uses. The current designated uses in the tidal portions of the Chesapeake Bay are for the
protection of aquatic life and have a dissolved oxygen criterion of 5 mg/l. As the Technical Support Document
illustrates, two factors-natural conditions and human-caused conditions that cannot be remedied-are likely to be
sufficient justification for showing why the current designated uses cannot be met, particularly in the deeper waters
of the Bay.
The Technical Support Document
also provides information used to
develop five refined designated use
categories, or habitat zones, and
includes their geographic and
temporal extent, or 'boundaries.' All
of these designated uses are based
on the needs of living resources, as
well as the bathymetry, hydrology,
physical features and natural
stratifications of the Bay's waters.
The Chesapeake Bay Program
partners have recommended that the
following five aquatic life designated
uses, illustrated at right, be applied to
the appropriate habitats in the
Chesapeake Bay and its tidal
tributaries:
Migratory fish spawning and
nursery;
Shallow-water bay grass;
Open-water fish and shellfish;
Deep-water seasonal fish and
shellfish; and
Deep-channel seasonal
refuge.
Implementation Tiers
To explore the attainability of the refined designated uses from a technological perspective, the EPA and its partners
developed implementation tier scenarios. Each tier represents a specific 'level-of-effort' combination of best
management practices (BMPs) and wastewater treatment upgrades. Associated with each tier are load reductions
for nitrogen, phosphorus and sediment determined by the technologies and levels of implementation assigned to the
tier.
These 'level-of-effort' scenarios range from Tier 1 (which represents current level of implementation throughout the
watershed, plus regulatory requirements implemented through the year 2010), up to a limit of technology scenario
referred to as E3 or 'Everything, Everywhere by Everyone.' Two other scenarios, Tier 2 and Tier 3, were also
developed to represent intermediate levels between Tier 1 and E3.
The tiers are designed to represent potential technological levels of effort and do not represent actual programs
jurisdictions may implement to meet water quality standards. Rather, these tiers are assessment tools to determine
potential load reductions achievable by various levels of technological effort and were modeled to determine water
The Chesapeake Bay Program is restoring the Bay through a partnership among the U.S. Environmental Protection Agency representing the federal
government, the State of Maryland, the Commonwealth of Pennsylvania, the Commonwealth of Virginia, the District of Columbia, the Chesapeake Bay
Commission, and participating citizen advisory groups.
Conceptual illustration of the five recommended Chesapeake Bay
tidal-water designated uses.
A. Cross-Section of Chesapeake Bay or Tidal Tributary
Shallow-Water
Bay Gtb3s Uae
Open-Water
Fish andShelHish Use
Deep-Water
Seesifial Rsh and
3-elNish Use
Deep-Channel
Seasonal Fteluge Uae
B. Oblique View of Ihe Chesapeake Bay and its Tidal Tributaries
Migratory Fish
Spawnrg and
i Nursery Use
Open-Water
Fish and Shallish Use
Dee p-Wa ter
Seasonal Fish and
Deep-Channel
Seasonal Fleluge Use
Shellfish Use

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The Use Attainability Analysis Technical Support Document and Economic Analyses Document
Page 3
quality responses. The Technical Support Document presents the results of the water quality model analyses by tier
to estimate the level of attainment achieved within each designated use.
Based on the nutrient and sediment reductions estimated from the tiers, and results of the water quality model
analyses, the Technical Support Document provides information showing that the designated uses can be realized
for most segments of the Chesapeake Bay under load reductions represented by the E3 scenario. A limited number
of segments, particularly for deep-water uses in certain mainstem segments, would not achieve full attainment at Tier
3 implementation levels.
Implementation Tiers Cost Development and the Economic Analyses Document
A companion piece to the Technical Support Document is the Economic Analyses of the Nutrient and Sediment
Reduction Actions to Restore Chesapeake Bay Water Quality (Economic Analyses). The Economic Analyses
document provides capital and annualized cost estimates for technologies and BMPs defined in each tier. Costs are
presented for the Tier 1 - 3 scenarios, but not for the E3 scenario as the implementation of the tier is considered
physically implausible. Annualized costs developed for the Economic Analyses consist of capital costs amortized
overtime, plus annual operating and maintenance costs to continue the implementation of each BMP. Cost
estimates and total nitrogen reduction for each tier are provided below.
Cumulative Load Reductions and Costs for the Chesapeake Bay Watershed
Tier
Total Nitrogen Reduction from
levels in 2000
(million pounds/yr)*
Capital Costs
(in millions of 2001
dollars)
Annualized Costs
(in millions of 2001
dollars)
Tier 1
23.9
$1,391
$196
Tier 2
63.5
$3,593
$553
Tier 3
104.0
$7,713
$1,125
E3 (Limits of
Technology)
168.4
not costed
not costed
* Phase 4.3 of the Chesapeake Bay Programs Watershed Model.
Current modeling estimates that approximately 283 million
pounds of nitrogen entered Chesapeake Bay in 2000.
Economic Impact Analysis
The Economic Analyses document also provides a summary of screening-\eve\ social and economic impacts that can
be used to show where substantial and widespread impacts may occur, and where more comprehensive analyses
need to be focused. In-depth analyses performed by the jurisdictions would need to be completed to make a final
determination of social and economic impacts. Each jurisdiction may also choose to use the screening-level
economic information to determine where and how much public financial assistance will be most effective.
Costs and screening-level impact information provided in the Economic Analyses are not used to delineate the
designated use boundaries. Through their own processes, the states and the District of Columbia will determine
affordability and their own final designated use boundaries.
For more information on restoring Chesapeake Bay water quality, please visit
http://www. chesapeakebay.net/restoringwater. htm.
The Chesapeake Bay Program is restoring the Bay through a partnership among the U.S. Environmental Protection Agency representing the federal
government, the State of Maryland, the Commonwealth of Pennsylvania, the Commonwealth of Virginia, the District of Columbia, the Chesapeake Bay
Commission, and participating citizen advisory groups.

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