Methodology to Assess Risk and Uncertainty of Drinking Water Contaminant Exposure

摘要

A need exists to couple groundwater models of contaminant transport to water distributionmodels due to the large percentage of the population that depends on groundwater,the largenumber of contaminated sites,and the fact that most sit s have groundwater impacts. In 1997,the National Priorities List (also known as Superfund) consisted of 1,405 sites,most of whichhad drinking water impacts through contaminated groundwater. Approximately 50% of urbanAmericans and 95% of rural Americans depend on groundwater as their primary source o fdrinking water ater 1. Contaminant transport and water distribution models can be used to assessthe historical risk of drinking water contaminant exposure from a water distribution systemthat has been contaminated at a well head. A case study site has been selected to demonstratethis approach.A two-dimensional finite element integrated depth groundwater flow and contaminan ttransport model was developed for an unconfined aquifer. Transient simulations for bot hgroundwater flow and contaminant transport were performed over a 25 year period t oincorporate the fluctuating pumping rates from several municipal wells screened in th econtaminated aquifer.