Groundwater

Groundwater (aquifer, aquitard, 3 type wells)

Surface water cycle

Shipot

AlapahaRiver2002

Burg Zusameck 5

Groundwater is the water located beneath the Earth's surface in soil pore spaces and in the fractures of rock formations. A unit of rock or an unconsolidated deposit is called an aquifer when it can yield a usable quantity of water. The study of groundwater is called hydrogeology.

Groundwater is recharged from, and eventually flows to, the surface naturally; natural discharge often occurs at springs and seeps, and can form oases or wetlands. Groundwater is also often withdrawn for agricultural, municipal, and industrial use by constructing and operating extraction wells. The study of the distribution and movement of groundwater is hydrology, particularly aquifer hydrology.

Characteristics

Groundwater flows due to the force of gravity and the pressure differences in the water itself. Its movement is significantly slower than the flow of water in rivers or streams, due to the porosity of subsurface materials. Groundwater can be involved in the natural process of water cycle (also known as the hydrological cycle), where it plays a vital role in the subsurface part of the cycle.

Aquifers

An aquifer is a layer of porous substrate that contains and transmits groundwater. When water can flow directly between the surface and the saturated zone of an aquifer, the aquifer is unconfined. The deeper parts of unconfined aquifers are usually more saturated since gravity causes water to flow downward. The upper surface of the saturated zone is called the water table or phreatic surface. Below the water table, where in general all pore spaces are filled with water, is the phreatic zone.

Confined aquifers are those in which an impermeable dirt/rock layer exists that prevents water from seeping into the aquifer from the ground surface located directly above. Instead, water seeps into confined aquifers from farther away, where the impermeable layer ends or is breached by a fault. Water in confined aquifers is under increased pressure compared to the water in unconfined aquifers. This can create artesian wells that flow freely without the need for pumping.

Groundwater Quality

The quality of groundwater, which can be affected by the geological composition of the aquifer, the residence time of the water, and the quality of the recharged water, is an important concern. Contaminants from human activities, such as industrial waste, agricultural chemicals, and improper disposal of waste, can also affect groundwater quality. Processes like filtration, dilution, and biodegradation can naturally attenuate some contaminants, but others may persist in the environment for long periods, posing risks to drinking water supplies and ecosystems.

Groundwater Management

Effective management of groundwater resources is critical for ensuring sustainable water supply and protecting the natural environment. This involves monitoring groundwater levels and quality, regulating the location and amount of groundwater extraction, and protecting recharge areas. Groundwater management is a challenge that requires balancing the needs of different users while protecting the aquifer from overuse and contamination.