Long-Term Water Quality Monitoring

Challenging conditions in the field often prevent effective long-term deployment of water quality monitoring instruments. Algae, biofouling, and pollutants have long presented problems, and can quickly cause data inaccuracies in unattended monitoring applications. In response to customer requests for an instrument that could withstand harsh conditions for weeks at a time, YSI developed the 6600 EDS sonde for extended deployments.

The advanced technology of the YSI 6600 EDS extends deployment by preventing probe fouling. Integral wipers automatically clean the sonde’s sensors, keeping them free of zebra mussels, algae, and debris. YSI’s patented rapid-pulse dissolved oxygen sensor provides unprecedented accuracy and longevity in long-term deployments.

When faced with the task of monitoring the impacts of an Ohio River hydroelectric plant for water quality, one consultant chose 6600 EDS sondes. Three sondes were deployed, one upstream and two downstream of the plant, to measure dissolved oxygen, conductivity, temperature, pH, turbidity, and chlorophyll.

The effectiveness of the 6600 EDS was proven after a successful 120-day deployment in the Ohio River. Post-calibration indicated less than a 3% drift on all parameters. Wipers successfully kept the sensors clean and free of debris, despite heavy biofouling and zebra mussel build-up elsewhere on the sonde. No cleaning or re-calibration was needed during the study.