Sources of Water

Sources of Water

• Water is used for various purposes such as cleaning, drinking, agricultural irrigation, and generating electricity from hydroelectric power.
• There are two main categories of water sources: groundwater and surface water.
• Groundwater is water below the surface of the ground, which can be found just below the soil or in an aquifer.
• Surface water is water above ground, including streams, rivers, and lakes.

Groundwater

• Aquifers are underground water reservoirs made of permeable rock that can hold water for many years.
• Aquifers do not fill quickly and can take a long time to recharge.
• Groundwater is removed through wells and is used for agricultural irrigation, drinking water, municipalities, and commercial and industrial uses.

Removal of Groundwater

• Aquifer depletion occurs when more water is pumped from the aquifer than is allowed to recharge, causing serious problems in the landscape.
• Over-extraction of groundwater can cause land subsidence, which may create dangerous sinkholes.
• Other issues that may arise from aquifer depletion include less water reaching streams, rivers, and lakes, dried up wells, a lowered water table, and salt water entering the groundwater supply.

Removal of Surface Water

• Surface waters, including streams, lakes, and rivers, can also be overdrawn, affecting ecosystems and human needs.
• Examples of overdrawn surface waters include the Colorado River, the Rio Grande, the Nile, and the Yellow River in China.
• The Aral Sea in Central Asia is a severe example of surface water depletion, resulting in a hostile environment, economic disaster, and loss of agriculture and fishing jobs.

Effects of Irrigation

• Irrigation removes large amounts of water from both below and above ground and adds dissolved salts back into the soils, leading to salinization.
• Salinization of soils prevents plants from taking up water, reducing crop yield and affecting the ecosystem.
• Salty soils can also contaminate surface waters and groundwater supplies.