ABSTRACT
This chapter defines groundwater and aquifers and discusses the physical properties of soils, liquids, vadose zones, and aquifers. Groundwater has been a major source of water supply throughout the ages. Groundwater is contained in geological formations, called aquifers, which are sufficiently permeable to transmit and yield water. Two types of aquifers are confined aquifers and unconfined aquifers. Natural soils consist of solid particles, water, and air. Soil classification divides soils into groups and subgroups based on common engineering properties such as texture, grain size distribution, and Atterberg limits. The pressure of water in the vadose zone is negative, and the negative pressure head or capillary pressure is proportional to the vertical distance above the water table. An aquifer is characterized by the three physical properties: hydraulic conductivity, transmissivity, and storativity. The theory of groundwater flow originates with Henry Darcy who published the results of his experimental work in 1856.
