Groundwater Motion
Groundwater motion is the movement of water through porous sediment and rock beneath the Earths surface. It is one of the major forms of hydrological cycle and a key element of water management worldwide. Groundwater motion is the major source of water for human consumption, agriculture and industry, supplying more than 99percent of all freshwater used by mankind.
Groundwater is created when soil and sand absorb rain or snow. The absorbed water becomes part of underground water reserves, which are regarded as groundwater. Water that is available in the Upper layers of the ground is generally easier to access and use, while water stored in lower layers can be more difficult or sometimes even impossible to access. Groundwater can be found in different types of rocks, from porous sands to compacted limestones and rock.
Water that penetrates the ground moves in various directions, depending on its environment and various factors. In porous soils, it may move in a horizontal direction, levitating upward due to the phenomenon of capillary action. Other factors such as ground slope and gravity can also play a role in the motion of water underground. When the slope of the land is steep, then the water will move quickly, while in flat land it might move more slowly. A layer of impermeable stones will cause water to accumulate underneath it, increasing its pressure level.
Water may move underground in three ways: by direct precipitation, by subsurface water flow, and by leaking from rivers and lakes. In areas where rainfall is rare or limited, groundwater is usually the main way to replenish the water reserves.
Groundwater may also travel through fractures in rocks, called fractures fissures, which create a connected network throughout the underground of the Earth. Such fractures can be caused by different tectonic activities, such as earthquakes and volcanic eruptions, as well as by shifting rocks due to weather conditions. Subterranean water can also seep out of rocks, through a process known as percolation.
Groundwater can travel across long distances and may reach a lake or river far away. This type of water motion is known as regional groundwater motion. Because ground water often carries with it minerals and salts that are not found in the environment, it may cause an impact on the water quality of a lake or river. Such water is sometimes referred to as local-scale water motion, due to its impact on the inside of an aquatic environment.
The nature and properties of the ground will determine the speed at which water moves through it. Water stored in confined aquifers usually travels faster than that stored in unconfined aquifers. Furthermore, the direction of underground water flow is usually determined by the pressure gradient, which in turn is dictated by the land slope and the type of soils and rocks present.
Part of the water that is present in the ground is also lost through evaporation. Evapotranspiration is a natural process that occurs in certain environments, where water stored in the ground is transported through vegetation and then evaporated by the sun.
Groundwater motion is an important natural process and is a key factor in water management. Knowing how groundwater moves helps us to optimize the usage of our resources, protect water quality and plan for potential emergencies and other water-related issues.
