DATAFLOW is a compact, self-contained surface water quality mapping system, suitable for use in a small boat operating at speeds of about 25 KT. The system collects water through a pipe ("ram") 
deployed on the transom of the vessel, pumps it through an array of water quality sensors, and then discharges the water overboard. The system collects samples approximately once every 3-4 seconds. The DATAFLOW system utilizes a YSI 6600 multiparameter, sonde equipped with a flow-through chamber which gives readings on water temperature, salinity, pH, chlorophyll, turbidity, and dissolved oxygen. The sonde transmits data collected from the sensors directly to a 600 MHz embedded computer board contained in a waterproof Pelican case using a data acquisition system created with LabView software (National Instruments, Inc.). Custom software written in the Lab View environment provides for data acquisition, display, control, and storage.
Real-time graphs and indicators provide feedback to the operator in the field, ensuring quality data is being collected. The system is also equipped with a Garmin GPSMAP 168 Sounder. This unit serves several functions including chart plotting, position information, and depth. The unit is WAAS (Wide Area Augmentation System) enabled providing a position accuracy of better than three meters 95 percent of the time.
DATAFLOW cruises take place once a month in each of the Chesapeake Bay Program Segment of interest. Two types of cruise tracks are utilized depending on the river morphology of the segment being monitored. Due to the width of larger segments such as the York River Polyhaline (YRKPH), a series of tracks running parallel to the shoreline along fixed depth contours is followed. The track follows the shoreline along the <2 meter depth contour upriver, then turns down river following a mid depth contour (approximately 5 meters), it then goes upriver along the channel (>10 meters depth), then finishes with a down river leg along the other shoreline in the shallows. In narrower segments such as those in the Mattaponi and Pamunkey Rivers a single cruise track is used, traveling upriver to parallel the tidal advancement. Verification stations, five in each segment, are sampled for a number of parameters including total suspended solids, extracted chlorophyll, light attenuation, organic and inorganic nutrients, and dissolved oxygen via Winkler titration to verify that the YSI 6600 is functioning properly.