Groundwater recharge

Groundwater recharge or deep drainage or deep percolation is a hydrologic process, where water moves downward from surface water to groundwater. Recharge is the primary method through which water enters an aquifer. This process usually occurs in the vadose zone below plant roots and, is often expressed as a flux to the water table surface. Groundwater recharge also encompasses water moving away from the water table farther into the saturated zone.[1] Recharge occurs both naturally (through the water cycle) and through anthropogenic processes (i.e., “artificial groundwater recharge”), where rainwater and or reclaimed water is routed to the subsurface.

Groundwater that recharges an aquifer
This article needs additional citations for verification. (November 2008)
Water balance

. . . Groundwater recharge . . .

Groundwater is recharged naturally by rain and snow melt and to a smaller extent by surface water (rivers and lakes). Recharge may be impeded somewhat by human activities including paving, development, or logging. These activities can result in loss of topsoil resulting in reduced water infiltration, enhanced surface runoff and reduction in recharge. Use of groundwater, especially for irrigation, may also lower the water tables. Groundwater recharge is an important process for sustainable groundwater management, since the volume-rate abstracted from an aquifer in the long term should be less than or equal to the volume-rate that is recharged.

Recharge can help move excess salts that accumulate in the root zone to deeper soil layers, or into the groundwater system. Tree roots increase water saturation into groundwater reducing water runoff.[2]Flooding temporarily increases river bedpermeability by moving clay soils downstream, and this increases aquifer recharge.[3]

Artificial groundwater recharge is becoming increasingly important in India, where over-pumping of groundwater by farmers has led to underground resources becoming depleted. In 2007, on the recommendations of the International Water Management Institute, the Indian government allocated 1,800 crore (equivalent to 46 billion or US$610 million in 2020) to fund dug-well recharge projects (a dug-well is a wide, shallow well, often lined with concrete) in 100 districts within seven states where water stored in hard-rock aquifers had been over-exploited. Another environmental issue is the disposal of waste through the water flux such as dairy farms, industrial, and urban runoff.

Wetlands help maintain the level of the water table and exert control on the hydraulic head.[4] This provides force for groundwater recharge and discharge to other waters as well. The extent of groundwater recharge by a wetland is dependent upon soil, vegetation, site, perimeter to volume ratio, and water table gradient.[5] Groundwater recharge occurs through mineral soils found primarily around the edges of wetlands.[6] The soil under most wetlands is relatively impermeable. A high perimeter to volume ratio, such as in small wetlands, means that the surface area through which water can infiltrate into the groundwater is high.[7] Groundwater recharge is typical in small wetlands such as prairie potholes, which can contribute significantly to recharge of regional groundwater resources.[7] Researchers have discovered groundwater recharge of up to 20% of wetland volume per season.[7]

. . . Groundwater recharge . . .

This article is issued from web site Wikipedia. The original article may be a bit shortened or modified. Some links may have been modified. The text is licensed under “Creative Commons – Attribution – Sharealike” [1] and some of the text can also be licensed under the terms of the “GNU Free Documentation License” [2]. Additional terms may apply for the media files. By using this site, you agree to our Legal pages . Web links: [1] [2]

. . . Groundwater recharge . . .