Our river and stream scientists follow strict protocols to ensure credible and defensible data is gathered about freshwater quality across the state. We follow the Quality Assurance Monitoring Plan and Standard Operating Procedures for ambient freshwater monitoring. These procedures include frequent calibration of meters and testing duplicate samples to eliminate errors.
The quality of our data is evaluated annually, and data aren't considered final until after this evaluation.
Our work relies on sound freshwater data that is used to assess the health of the state's waterbodies. Data help us to identify trends and serve as the foundation for federal water quality 303(d) listings and subsequent water-cleanup investigations. Our Freshwater Quality Monitoring team follow strict protocols for sampling and processing to assure we produce quality data supporting water quality protection and cleanup across the state.
The Quality Assurance Monitoring Plan (QAMP) and Standard Operating Procedures are linked below.
Meters are calibrated frequently
We carefully and frequently calibrate the meters we use in the field. Conductivity meters are calibrated twice daily and pH meters three times. We also check the calibration whenever a pH reading exceeds state standards. Modified Winkler titrations are used to measure dissolved oxygen because they are more accurate than meters, and because samplers often change elevation between sample stations.
Quality is assured by duplicate samples