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Brett D Johnston


I am a hydrologic technician at the Caribbean-Florida Water Science Center in Orlando, FL. My work is focused on the operation and maintenance of continuous monitoring gages, collection of field measurements, and associated analysis of surface water and water quality records. Data collection methods typically involve the use of advanced sensors, such as those utilizing hydroacoustic or optical (attenuation, absorbance, and fluorescence) technologies. I have a prominent interest in investigating the uses of field sensor metadata for real-time diagnostics and quality assurance, which can aid in the collection of high quality data from new and evolving technologies.



Discharge computation utilizing index-velocity and complex-spring methods, as well as water quality parameters; temperature, specific conductance, dissolved oxygen, and algal fluorescence (chlorophyll-a and phycocyanin), at various gaging stations in the Lower St. Johns River Basin.

Development and execution of a comprehensive test plan to evaluate the performance of a multi-channel, algal classification fluorometer.



Johnston, B.D. (2016, May). Continuous UV Nitrate Monitoring in Central Florida: Challenges and Opportunities. Presented at the 10th National Monitoring Conference, Tampa, FL.

Johnston, B.D. (2016, June). Continuous Nitrate Monitoring in the CFWSC: Sensor Optimization and Quality Assurance. Presented at the 2016 Caribbean-Florida Water Science Center Data Meeting, Key Largo, FL.

Pellerin, B.A., Meppelink, S.M, Johnston, B.D. (2017, June). Optical Sensor Techniques and Methods. Presented at the Continuous Monitoring Workshop, Norcross, GA.

Johnston, B.D. (2019, August). Evaluating an Algal Classification Sensor: A Strategy for Testing New Monitoring Technologies. Presented at the National Water Data Training Workshop, Columbus, OH.



Rosen, B.H., Loftin, K.A., Graham, J.L., Stahlhut, K.N., Riley, J.M., Johnston, B.D., and Senegal, S., 2018, Understanding the effect of salinity tolerance on cyanobacteria associated with a harmful algal bloom in Lake Okeechobee, Florida: U.S. Geological Survey Scientific Investigations Report 2018–5092, 32 p.,

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