AWWA WQTC71408

This powerpoint presentation begins by providing a brief overview of water quality sampling including continuous versus grab samples. The study objective was to examine sampling programs for two different case study distribution systems to determine the tradeoffs between continuous and grab samples. Study methodology included: using models for chlorine concentration, create synthetic database to test different sampling designs (simulated sampling to determine efficiency of each sampling design); and, investigate the impact of storage volume on the variability of chlorine and test hypothesis that larger storage volume is linked to higher temporal variability in chlorine. Presentation conclusions indicate that: use of continuous monitors as a 1:1 substitute for grab samples may not increase sampling efficiency, even for systems with relatively high temporal variability; continuous monitors are more helpful as a supplement to grab samples but only when locations are carefully selected; and, findings have implications for regulators considering how to integrate continuous monitors into compliance sampling programs. Includes tables, figures.