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GROUND WATER SUPPLIES
Ground water is subsurface water occupying the zone of saturation. A water bearing geologic formation which is composed of permeable rock, gravel, sand, earth, etc., and yields water in sufficient quantity to be economical is called an aquifer. Unconfined water is found in aquifers above the first impervious layer of soil or rock. This zone is often referred to as the water table. Water infiltrates by downward percolation through the air-filled pore spaces of the overlying soil material. The water table is subjected to atmospheric and climatic conditions, falling during periods of drought or rising in response to precipitation and infiltration. A confined aquifer is defined as the aquifer underlying an impervious bed. Areas of infiltration and recharge are often some distance away from the point of discharge. This water is often referred to as being under artesian conditions. When a well is installed into an artesian aquifer, the water in the well will rise in response to atmospheric pressure in the well. The level to which water rises above the top of the aquifer represents the confining pressure exerted on the aquifer. Materials with interconnecting pore spaces such as unconsolidated formations of loose sand and gravel may yield large quantities of water and, therefore, are the primary target for location of wells. Dense rocks such as granite from poor aquifers and wells constructed in them do not yield large quantities of water. However, wells placed in fractured rock formations may yield sufficient water for many purposes.

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What Is Engineering?

Do you ever find yourself wondering how something works or how a structure was built? Well, then you might be destined for a career in engineering. The field of engineering uses science to come up with solutions to problems in the real world. Depending on what type of engineering it is, this process will look different in many ways. Let's explore some of the major types of engineering in this lesson.