Water resources are critical for life, and are also essential for economic development. These resources are, however, depleting at a faster rate, resulting in water stress and its scarcity in coming years. Due to various reasons, the major source of water supply is groundwater for most regions in India.

The NITI Aayog report (2018) says that India’s water demand will exceed water supply by a factor of two by 2030. These call for urgent attention for ensuring water security in the coming years.

Declining groundwater

According to World Water Development Report 2015 (UNESCO), India is a frontrunner in groundwater extraction. The water table is going down in several areas. The reasons for this decline are multi-fold; overexploitation of shared water resources, mismanagement, and climate change impact, among others.

Several metropolitan cities are already facing difficulties meeting water demand due to high population density and limited water resources. For example, Delhi has a water supply of approximately 930 million gallons a day (mgd) while its demand is 1,380 mgd. The Delhi Jal Board (DJB) plans to meet this growing demand through groundwater sources. This will put further stress on the over-exploited groundwater sources in Delhi.

For improving access to water, the government has given special focus to implementing “source sustainability measures such as recharge and reuse through grey water management, water conservation, rainwater harvesting”. A campaign to “Catch the rain, where it falls, when it falls”, which aims to push stakeholders to create appropriate rainwater harvesting structures, has also been launched.

Several government schemes, for example, Atal Bhujal Scheme, are currently focusing on aquifer mapping to construct artificial reservoirs and rainwater harvesting structures. These mapping techniques take into account hydrogeology and source water availability. These efforts are expected to reduce groundwater depletion. Rainwater harvesting (RWH) process will help in this regard.

Artificial recharge

The rainwater harvesting process incorporates collection and storage of collected rainwater with the help of artificially designed systems. Such artificial recharge structures could be a major intervention to augment the water supply, thereby improving the groundwater resource availability. For both urban and rural contexts, the traditional methods along with modern storage options can address the root cause of water security.

Once installed, RWH becomes a simple low-cost technique that offers multiple benefits. The water storage tank is usually the principal capital investment. The installation of RWH structures is more cost-effective when done at the construction stage of the building. Even if the installation takes place at a later stage, the cost gets reduced drastically when taking a parsimonious approach such as the use of underground or overhead plastic tanks. The installation of a RWH system also saves total cost when the water is used for vegetable irrigation.

Agenda ahead

Efforts that could help attain the target of reducing dependency on groundwater, thereby enhancing water security, include rejuvenation and recharge of natural and constructed water bodies, increased reuse of treated wastewater through local sewage treatment plants and well-designed rainwater harvesting systems across residential and commercial areas. These efforts must be facilitated by the Central and State governments.

There is a need for stringent policy initiatives for long-term and sustainable solutions. An integrated water management plan must be brought up by local bodies and implemented at the local level. This approach will ensure better water security in the country.

Sarkar is Distinguished Fellow at The Energy and Resources Institute (TERI) and former Secretary, Ministry of Water Resources, and Tigala is Associate Fellow, TERI