Submerged appurtenances and pipelines: An assessment of water levels and contaminant occurrence

摘要

Submerged air/vacuum valves (AWs) and pipe leaks are potential entry points of contaminated water into distribution systems under low-pressure. Water levels in 20 valve vaults and 17 groundwater wells were monitored weekly for eight months. The resulting data showed that water mains and AWs were commonly submerged in the investigated system. Urban runoff was the dominant source of flooding in 11 of the 16 monitored vaults containing water. A subset of 14 vaults and 10 piezometers were sampled for microbial and chemical parameters. Concentrations of chemical contaminants generally did not exceed drinking water standards. However, high counts of microbial fecal indicators were detected in numerous vaults. Runoff volumes of up to 255 L/mm of rainfall were found to enter a tested vault, and runoff water was identified as the main source of pesticides, pharmaceuticals and personal care products (PPCPs), microbial fecal indicators, and hydrocarbons in vaults.