Need for and Use of High-Resolution Turbidity Monitoring in Managing Discoloration in Distribution

Abstract

Turbidity measurements at high temporal resolution from several sites within the distribution network gave a more complete record of the variability of turbidity than previously possible, showing that there are frequent movements of sediment at low concentrations. Knowledge of the availability of sediment was shown to be important to the prediction of turbidity, as the correlation of hydraulic disturbance (indicated by pressure change) alone with changes in turbidity was weak. These data sets also showed with greater confidence than previously possible that mains flushing frequently resulted in the incomplete removal of sediment. Given that knowledge of sediment availability is required to reduce uncertainty in the prediction of turbidity, measurements at high temporal and spatial resolutions were used to calculate sediment mass balances and determine sediment distribution within the study area. A net accumulation of 0.923 kg of sediment was observed within 2,482 m of the main, equivalent to