When groundwater (with added minerals by nature) reaches an aquifer, it moves slowly at rates of 7 to 60 centimeters per day in an aquifer. That is why water could remain in an aquifer for thousands of years.
Groundwater is naturally recharged by rainwater, snow-melt and through water veins of the lakes and rivers.
The Earth's water is distributed in the following way: 97 percent is found in the oceans, 2 percent is frozen at the poles or in glaciers, and the remaining 1 percent is our source of freshwater. Of this 1 percent, approximately 96 percent is groundwater, as stated by the National Oceanic and Atmospheric Administration (NOAA). The remaining freshwater can be located at the surface in streams, lakes, rivers, and wetlands.
Groundwater plays a crucial role in human existence and the sustainable development of society. It is responsible for providing drinking water to at least 50% of the global population and contributes to 43% of all water used for irrigation (FAO, 2010). Additionally, 2.5 billion people worldwide rely entirely on groundwater resources to fulfill their basic daily water needs (UNESCO, 2012).
Groundwater extraction accelerates its discharge, disrupting natural flow dynamics. Reservoir construction upstream reduces the replenishment of groundwater by surface water in the plain. Consequently, declining groundwater levels lead to a host of environmental and geological concerns.
Deforestation is directly proportional to decreasing the groundwater.
Construction of reservoirs in the upstream areas has reduced groundwater recharge by surface water in the plain.
Unplanned infrastructure - which covers the land more than enough.
Plastic waste makes the layer which prevents water from going underground.
Untreated sewer water and waste.
Indiscriminate excavation of mines and minerals that destroys the veins of water.
Linking rivers to each other will stop their natural flow and that will damage the land's fertility.
Toxic activities(using chemical fertilizers and pesticides in agriculture, suppressing toxins in the soil, etc.) of humans on land.
We must acknowledge that our vast oceans aren't a limitless solution to our water needs. When extracting pure water from seawater, the byproduct brine is generated due to salt content. Reintroducing this brine back into the ocean leads to a detrimental increase in salinity, causing harm to numerous organisms unable to tolerate such conditions.