There are 3 data sets. Two zip files contain paired biological (benthic macroinvertebrate genera) (Data Biological.zip) and water quality data (Data Environmental.zip). These were used to estimate background specific conductivity from these state data and estimate the HC05 using the field based extirpation concentration method (USEPA 2011). The zipped files (Griffith ion MG20150729) contains two csv miles with ions summaries and ion and specific conductivity data from the combined EPA survey data. This dataset is associated with the following publication: Cormier, S., L. Zheng, R. Novak, and C. Flaherty. A flow-chart for developing water quality criteria from two field-based methods. SCIENCE OF THE TOTAL ENVIRONMENT. Elsevier BV, AMSTERDAM, NETHERLANDS, 633: 1647-1656, (2018).