Correlating Trihalomethane Data

Abstract

Because of its importance as a drinking water supply for 20,000,000 Californians, the Sacramento‐San Joaquin delta and its tributaries have received much attention with respect to drinking water quality in general and trihalomethane formation potential (THMFP) in particular. Although THMFP is a good measure of source water precursor levels, it gives only limited insight into typical finished water quality. Yet water supply decisions must ultimately consider how precursors at the source translate into THMs at the tap. This paper develops an effective tool for estimating simulated distribution system THM (SDS‐THM) species concentrations from source water precursor measurements such as THMFP. Empirical relationships for SDS‐THM formation are successfully calibrated and verified with data collected over a 14‐month period from six locations in California. The framework is shown to be a necessary link in evaluating source water management alternatives, even within a planning context where model results are reported as incremental changes between base and plan conditions.