30 
monitoring program will be combined with intensive data collection in all spatial 
assessment units. Funding is not currently available to support monitoring at the 
“recommended” level. The fixed-station monitoring is expected to continue into the 
future, so data should be available at the “marginal” level for all spatial assessment 
units. With the implementation of the Chesapeake Bay shallow-water monitoring 
program in 2001, combined with a growing network of high-frequency observing 
system deployed in the Bay tidal waters, monitoring will reach the “adequate” level 
across all spatial assessment units with time. 
To enhance the monitoring information from the coordinated Chesapeake Bay water 
quality and shallow-water monitoring programs, jurisdictions are encouraged to 
include data from other sources as appropriate. Consistent with the 2003 EPA- 
published Chesapeake Bay water quality criteria assessment guidance, the states and 
the District are encouraged to compile data from sources such as state and federal 
monitoring agencies, local governments, universities, environmental organizations, 
and citizen monitoring groups (U.S. EPA 2003a). Such data could prove significant 
in enhancing the spatial coverage of the existing Chesapeake Bay water quality 
monitoring program. The jurisdictions must ensure, however, that the data are appro¬ 
priate for use in the Chesapeake Bay criteria attainment assessment methodology. 
Data need to be of documented quality and adequate quantity as indicated above. 
The jurisdictions also must ensure that the data are collected at an appropriate scale 
and are representative of a given area or volume of a specific spatial assessment unit. 
The Chesapeake Bay Program spatial interpolator uses data collected at all locations 
and defines how much of that area or volume can be characterized by data from a 
particular location (see Chapter 2 and Appendix D for details). Thus, a small tidal 
embayment may be characterized by data from a single site. If that site is not located 
properly (e.g., in a small creek, off a pier in shallow water, off a beach), the assess¬ 
ment of the entire embayment may rest on potentially biased information. Similarly, 
if data are collected intermittently at some sites, the spatial assessment unit may be 
characterized inconsistently at times. 
To use data collected through non-Chesapeake Bay Program monitoring programs in 
Chesapeake Bay water quality criteria assessments, they must be merged with the Chesa¬ 
peake Bay Program monitoring program data appropriately. The assumption is that these 
water quality data were collected on different time (more infrequent) and space (well 
away from the mid-channel river, mainstem) scales than the Chesapeake Bay Water 
Quality Monitoring Program data. Therefore, these other data will be assigned a cruise 
designation based on the monthly collection time so that they can be interpolated along 
with the Chesapeake Bay Water Quality Monitoring Program data to generate the cumu¬ 
lative frequency distribution (see Chapter 2 and Appendix B for details). 
The states are encouraged to seek data from sources beyond the Chesapeake Bay 
Water Quality Monitoring Program, but should use such data with care to avoid 
biasing the assessment results for any particular portion of the tidal waters. Ideally, 
the states would work with the collecting agencies and institutions in advance to 
chapter iii 
Application of Chesapeake Bay Water Quality Criteria Assessment Procedures 
