89 
chapter \/BIi 
Updated Guidance for 
Application of Water Clarity 
Criteria and SAV Restoration 
Goal Acreages 
With publication of the Ambient Water Quality Criteria for Dissolved Oxygen, Water 
Clarity and Chlorophyll a for the Chesapeake Bay and Its Tidal Tributaries 
(Regional Criteria Guidance) (U.S. EPA 2003a) and the Technical Support Docu¬ 
ment for Identification of Chesapeake Bay Designated Uses and Attainability- 
(Technical Support Document) (U.S. EPA 2003b), the jurisdictions were provided 
with extensive guidance for how to determine attainment of the shallow-water bay 
grass designated use. 
Specifically, the EPA Regional Criteria Guidance document provided the following 
guidance to the jurisdictions: 
To determine the return of water clarity conditions necessary to support 
restoration of underwater grasses and, therefore, attainment of the shallow- 
water designated use, states may: 1) evaluate the number of acres of 
underwater bay grasses present in each respective Chesapeake Bay Program 
segment, comparing that acreage with the segment’s bay grass restoration 
goal acreage; and/or 2) determine the attainment of the water clarity criteria 
within the area designated for shallow-water bay grass use. The shallow- 
water bay grass use designated use area may be defined by either: 
1) applying the appropriate water clarity criteria application depth (i.e., 0.5, 
1 or 2 meters) along the entire length of the segment's shoreline (with excep¬ 
tion of those shoreline areas determined to be bay grass no-zone grow zones; 
see U.S. EPA 2003 [Technical Support Document ] for details); or 
2) determining the necessary total acreage of shallow-water habitat within 
which the water clarity criteria must be met using a salinity regime specific 
ratio of underwater bay grass acres to be restored within a segment to acres 
of shallow-water habitat that must meet the water clarity criteria within the 
same segment (regardless of specifically where and at what exact depth 
those shallow water habitat acreages reside within the segment). 
chapter vii 
Updated Guidance for Application of Water Clarity Criteria and SAV Restoration Goal Acreages 
