67 
Figure VII-2. Example of a continuous monitoring site and the generated 2004 dissolved oxygen data record 
at Fenwick Point in the Potomac River, Maryland. 
Source: Maryland Department of Natural Resources — www.eyesonthebay.net 
Overlap periods occur at each continuous monitoring site by using multiple sondes 
during routine biweekly maintenance runs to determine instrument drift. Instruments 
are pre- and post-calibrated and must meet rigorous QA/QC protocols. Two instru¬ 
ments are dedicated to each site. When one instrument is removed from the site for 
maintenance, it is measured against the newly calibrated instrument. At the same time, 
a field crew member takes a full suite of calibration samples for laboratory analysis. 
Satellite and cellular telemetry are implemented at a subset of continuous monitoring 
sites where resources permit. Data from these sites are assessed on a daily basis. 
Maryland shallow-water continuous monitoring data are available in near- or real¬ 
time on the Department of Natural Resources “Eyes on the Bay” website 
(www.eyesonthebay.net) (Figure VII-3). Virginia shallow-water continuous moni¬ 
toring data are available on the Virginia Institute of Marine Sciences website 
(www2.vims.edu/vecos/). The Chesapeake Bay Program website’s data hub 
(www.chesapeakebay.net/data) offers access to the complete quality assured 
Shallow-water Monitoring Program datasets for Maryland and Virginia. 
WATER QUALITY MAPPING COMPONENT 
The main purpose for collecting high-resolution water quality data is to provide reli¬ 
able water quality criteria assessments. However, Dataflow monitoring also provides 
insight into spatial complexities and localized phenomena and information for water 
quality modeling in shallow waters (STAC 2005). The data are useful in producing 
maps of the extent and patchiness of algal blooms, seasonal and inter-annual 
progressions, and localized water quality impairments. 
The Dataflow system is a small, fast-moving vessel that pumps surface water contin¬ 
uously from 0.5 meters below the water surface through a chamber surrounding the 
chapter vii 
Shallow-water Monitoring and Application for Criteria Assessment 
