Groundwater Quality Assessment and Hydrochemical Processes in Urbanizing Regions

Abstract

Groundwater is a vital source of drinking and irrigation water for rapidly growing cities, yet urbanization alters recharge, flow and chemical composition of aquifers. This article reviews approaches for assessing groundwater quality and interpreting hydrochemical processes in urbanizing regions. Sampling strategies, analytical quality control and graphical classification of hydrochemical facies are described, followed by the natural controls of rock weathering, evaporation, ion exchange and redox reactions. Anthropogenic sources including leaking sewers, landfills, industrial sites, road salt and stormwater are examined, with emphasis on nitrate, salinity and trace element contamination. Water quality indices, drinking water guidelines, multivariate statistics, geochemical modeling and environmental tracers are discussed as complementary tools for interpretation. Health risk assessment and management measures such as wellhead protection, sewer rehabilitation and managed recharge are outlined, and priorities for monitoring and research are identified for safeguarding urban groundwater.