"Water table" is a term that refers to the top of what is called the saturated zone, or the level at which the ground is entirely saturated with groundwater, or water that soaks into the soil. There are many factors that affect the water table in a given area, among them being climate, characteristics of the soil and human activities.
Greater precipitation, ice melt in the spring and summer and high humidity that prevents water from evaporating can raise the water table. If the water table rises to a very high level, additional heavy rainfall may cause flooding because the soil cannot absorb any more water. On the other hand, lack of precipitation and hot, dry weather that promotes evaporation can lower the water table.
Soil characteristics that affect the water table include permeability and composition. Soils with a high clay content are relatively impermeable, while sandy soils allow water to pass through and raise the water table. Compacted soils with small pores with little vegetation and rocky areas with little soil are also relatively impermeable compared to loose soils in dense, forested areas.
Human activities such as clear cutting, farming, pumping, irrigation and construction can affect the water table. For example, ground clearing, construction and increasing the slope of the ground can result in soil erosion and greater runoff that carries water away from an area before much of it can be absorbed. Heavy use of water, such as for irrigation, can also lower the water table, especially if precipitation is inadequate to replenish groundwater supplies.
By definition, factors that affect groundwater supplies subsequently affect the water table. Both are of vital importance because people depend on them as a source for water. According to Groundwater.org, groundwater supplies 98 percent of drinking water in the world. Groundwater is also used for other domestic, agricultural, commercial and industrial purposes. Some factors that affect the groundwater and water table can also affect water quality, such as human activities that discharge pollutants into the soil.