Hydrogeology

Abstract

Hydrogeology is the study of the movement of water through the subsurface geologic environment. This article reviews the basic concepts of groundwater flow through sediments and bedrock, and the key equations that are used to quantify the rates of groundwater flow. These equations are central to the formulation of numerical simulation models now routinely used to predict how a groundwater system will respond to imposed stresses, such as large-scale groundwater withdrawals or climate change. These stresses may modify groundwater – surface water interactions. Hydrogeology also involves the analysis of water chemistry changes along a subsurface flow path and investigations of the transport and fate of contaminants that enter the subsurface environment. These contaminants may exist as either dissolved solutes or as a separate liquid phase such as gasoline. This article presents the equations used to predict the evolution of solute concentrations in groundwater systems. Water filling the pore spaces in sediments and rocks has a key role in a number of geologic and geodynamic processes that occur within the upper crust of the earth; because of the influence of pore waters on the mechanical properties of a rock mass, and the large-scale redistribution of solutes and heat in crustal rocks.