Water storage

[1] Groundwater is located beneath the ground surface in soil pore spaces and in the fractures of rock formations.

In a confined aquifer, the upper surface of water is overlain by a layer of impervious rock, so the groundwater is stored under pressure.

[2] Aquifers receive water through two ways, one from precipitation that flows through the unsaturated zone of the soil profile, and two from lakes and rivers.

Water storage in the soil profile is extremely important for agriculture, especially in locations that rely on rainfall for cultivating plants.

[4] Wetlands are basically sponges that capture and slowly release large amounts of rain, snowmelt, groundwater and floodwater.

For example, Egypt's Aswan High Dam, built in the 1960s, has protected the nation from drought and floods and supplies water used to irrigate some 15 million hectares.

Because sediment is trapped by the Aswan High Dam, the Nile no longer delivers nutrients in large quantities to the floodplain.

Many of the 852 million poor people in the world live in parts of Asia and Africa that depend on rainfall to cultivate food crops.

For example, using small planting basins to 'harvest' water in Zimbabwe have been shown to boost maize yields, whether rainfall is abundant or scarce.

It has been suggested that the lack of proper tools and equipment for construction, leads to a system more likely to contain breaches, making them more susceptible to contamination from the environment and users.