Specific conductivity sensor performance: II. Field evaluation

Abstract

The US Environmental Protection Agency (USEPA) has issued guidance on the specific conductivity (EC25°C) of waters discharged from mined lands in the Appalachian Coal Belt Region of the USA. In this guidance, the USEPA states that these waters should have an EC25°C less than 300–500 μS cm−1. Such a requirement places great importance on accurately determining EC25°C. Building upon a laboratory-based evaluation of four types of commercially available continuous logging conductivity sensors, this study examined sensor performance in the more harsh and variable field environments at forested and mined land streams in eastern Kentucky. The objectives of this study were to calculate the white noise variance associated with each sensor type and to evaluate white noise variance in relation to variations in EC25°C and discharge. Results of the study indicate that predominant increases in EC25°C, and to some extent increases in discharge, explain between 35 and 65% of the white noise variance.