Comparison of Potential Risk on Two Managed Aquifer Recharge Sites from River Basin

Abstract

Drinking water production facilities are designed to filter contaminants that are ever-present in raw water. These facilities, however, pose risks of tap water contamination or water supply discontinuation in the event of a massive chemical spill. A managed aquifer recharge (MAR) offers the advantage of purifying surface water as well as maintaining water underground for extended periods of time, thus securing sufficient time for a response to contaminant infiltration and dramatically increasing consumer safety. However, contaminated aquifers are difficult to recover; accordingly, it is important that MAR sites engage in preemptive responses to chemical spills in order to protect their aquifers. This study assesses potential risks in order to quantify the detrimental impacts of chemical spills in cities located in river basins on drinking water supply facilities. The targets of analysis are two MAR sites in South Korea. The potential risk analysis offers grounds upon which aggressive basin management can be implemented to ensure water supply facility operation safety. The lack of data for available for analysis is addressed using a stochastic methodology that ranks cities in which MAR sites are endangered based on the cities' potential risk probability distributions. The results of the analysis show that water supply facilities surrounded by larger cities have relatively higher potential risks, and would, therefore, need to handle more management targets to prevent chemical spills. Furthermore, the proposed methodology contributes not only to potential risk management of existing water supply facilities, but also to MAR site selection.

A review on risk assessment in managed aquifer recharge

“…Ji and Lee (2016a, 2016b, 2017) proposed and applied a PRTR together with deterministic and stochastic methods to assess potential chemical risks for a MAR site. A PRTR provides data to determine (i) the quantity of emitted chemicals (discharged to water systems, soil, and the atmosphere) and (ii) the transfer of these chemicals (from their source to the MAR facilities) as a function of time.…”

“…Potential accumulated chemical risks are proposed to be determined from the toxicity of the chemicals, the distance from the source to the MAR site, and the total quantity of chemicals to be transferred from the source over time. If recorded data are lacking or predictions for future developments are intended, Ji and Lee (2016b, 2017) propose the application of PRTR in combination with a stochastic approach to estimate potential risks. The PRTRs can be used to carry out risk assessments as part of the HACCP procedure and/or the setup of WSP, such as was done by Ji and Lee (2017) for two different MAR sites.…”

“…If recorded data are lacking or predictions for future developments are intended, Ji and Lee (2016b, 2017) propose the application of PRTR in combination with a stochastic approach to estimate potential risks. The PRTRs can be used to carry out risk assessments as part of the HACCP procedure and/or the setup of WSP, such as was done by Ji and Lee (2017) for two different MAR sites.…”

“…Groundwater salinity or sodicity, dissolved reactive minerals (such as fluoride or pyrite), radionuclides or metals (such as arsenic), and chemical spills, among other things, can lead to a decrease in the quality of water recovered by MAR, and this may induce human health risks (Assmuth et al, 2016; Bartak et al, 2015; Bouwer et al, 2008; Bugan et al, 2016; Lee & Ji, 2016; NRMMC, 2009; Page, Dillon, Vanderzalm, Bekele, et al, 2010; Page et al, 2013; Swierc et al, 2005; Vanderzalm et al, 2011). Thus, even if the infiltrated (MAR source) water is of acceptable quality, subsurface contamination can lead to poor quality of water that is recovered by MAR for drinking water or irrigation use (e.g., Dillon et al, 2014; Ji & Lee, 2017). Heterogeneity of the aquifer and spatially and temporally varying groundwater transit times are among the factors that can influence chemical and pathogen retention or removal by natural attenuation processes (e.g., Swierc et al, 2005; Toze et al, 2010).…”

Water Recycling via Aquifers for Sustainable Urban Water Quality Management: Current Status, Challenges and Opportunities

“…This can be incorporated into groundwater models for optimal placement of new MAR schemes or to effectively manage recharge volumes to assist with the dilution of existing contaminants. In South Korea, the risks posed by siting new ASTR in two urban locations were assessed: Ji and Lee [131,132] highlighted that Pollutant Release and Transfer Registry (PRTR) data from selected sites are vital to planning new MAR and further develop a hazard analysis and critical control points methodology for river water used for ASTR. A promising area for future research is applying newly developed theoretical methods to predict pollutant release history and source location in groundwater to properly constrain placement of new MAR schemes.…”