Human Settlements
The development of well drilling techniques in the 19th century allowed numerous people to use groundwater as an easy and open access resource with a common-pool nature.
Groundwater thus became a key natural resource supporting human well-being and economic development, but also a widely misunderstood, undervalued, and inadequately protected resource.
In the coming decades, the groundwater dependence of innumerable cities appears to be intensifying, such that nearly 50% of the global urban population are believed today to be supplied from groundwater sources.
However, many urban poor live in peri-urban settlements, which are unplanned and lack legal status, and where public water infrastructure and services are not provided, leading to an increased use of private waterwells for urban self-supply.
Groundwater is often the most cost-effective way of providing a secure water supply to villages.
This is especially the case in Sub-Saharan Africa and South Asia where the rural population is large but dispersed.
However, groundwater in Sub-Saharan Africa is currently limited by a lack of investments in infrastructure, trained professionals and knowledge, rather than by a lack of renewable groundwater (which is often abundant).
The value of groundwater for societies should not be measured only by volumetric withdrawals, but also by the immense economic and health benefits it brings, with its good quality and its high drought reliability.
However, groundwater overexploitation is increasing within urban areas, often accompanied by land subsidence that affects urban infrastructures and saline-water intrusion.
In addition, the coexistence of on-site sanitation and groundwater supply is a serious concern for shallow sources, particularly in more densely populated villages. Persistent contamination of rural groundwater supplies with pathogens is estimated to affect about 30% of the total installations, having an impact on the marginalized the most.
Groundwater clearly plays a major role in urban water supply, as well as a critical role in water supplies to rural villages and settlements of displaced people worldwide; there is the need for water utilities to put a much more emphasis on protecting waterwells and springhead sources for a sustainable use of the resource.