Rebecca Bushway

Bushway, R., C. Monohan, J. Viers and D. Brown. Quantitative Percent Exceedance: A Method to Analyze Water Quality Data for Citizen Monitoring; A Case Study for the South Yuba River Citizen League. California State University, Chico. Fall 2013.


Long term water quality monitoring by citizen groups has produced large data sets, often with little or no capacity for data analysis beyond basic quality control. It is often beyond the  capability of citizen monitoring groups to analyze large sets of water quality data by available data analysis methods, and discern the biological importance of the results within naturally variable systems. To assist citizen monitoring groups with the evaluation of water quality data in their watershed, a new method of analysis was developed and subsequently validated. The method developed, Quantitative Percent Exceedance (QPE), was based on biologically important thresholds, and designed to be carried out by citizen monitoring groups with a basic software package (Microsoft Excel). Sites were categorized by exceedance from the standard using QPE, and compared to clusters obtained from hierarchical cluster analysis. The correlation between these categorizations was verified by X2 analysis. Categorizations obtained from hierarchical cluster analysis (HACE) were well correlated with those from QPE (p <0.001). QPE is an effective method for the categorization of sites based on biologically meaningful data that citizen monitoring groups can use to inform monitoring and remediation efforts in their watersheds, producing results that are statistically comparable to the accepted method of hierarchical cluster analysis.

Student Bio

Rebecca has been teaching in the Chico State Chemistry department, and just got a position to teach Chemistry at a private school in Florida.