Water scarcity is the lack of supply to meet the demand for water within a region. Droughts, floods, water pollution, waste / misuse of water, limited storage space for water, sea water intrusion and other socio-geographical factors contribute to water scarcity. Population growth, sea level rise and climate changes can hinder the sustainable use of water in a region. All of these are important in the Maldives.
Main type of drinking water used by the population
Estimation of water balance helps in identifying scarcity. Water balance is the flow of water in and out of a system. These assessments help in water management of water supply, agriculture, environment and industry.
Precipitation
There are long records for five stations distributed from North to South in the Maldives. The character of the annual rainfall shows the drier months at February and March. The Northern stations receive highest rainfall during the summer monsoon month of June. Southernmost stations show a peak in rainfall in December.
Evapotranspiration
Evaporation from soil or open water surfaces together with transpiration from plants / vegetation is known as evapotranspiration. The Maldives has a humid tropical climate which ensures a high rate of evapotranspiration throughout the year. The water recharged during the wet season is lost during the dry season due to water extraction and evapotranspiration losses.
Groundwater Storage
Only freshwater resource on these islands is a groundwater lens which floats atop a denser salt water layer.
If the groundwater is not potable, it is useful for secondary purposes including bathing, washing and toilet flushing.
Groundwater pollution caused a series of epidemics in the 1970s forcing the government and people to look for alternative sources of freshwater. In the absence of surface water resources, such as rivers and lakes, only viable options were rainwater harvesting and desalinization supplemented by imported bottled water. Of the three, the most economical option is rainwater harvesting.
Runoff
Runoff is the residual item that remains from rainfall after evapotranspiration and infiltration to the soil.