In 2015 severe flooding devastated the city of Chennai, killing hundreds of people. This month, the city faces a water crisis as its reservoirs are nearly dry. The crisis was brought on not just due to lack of water, but to lack of proper management, according to an analysis by the Water Resources institute (WRI).
Baseline water stress in the region is high, with over 80% of the water supply available being used up for agricultural, industrial and domestic purposes each year. Pollution of water sources by untreated sewage and a rising water demand for a growing population and economy also contribute to the crisis. Moreover, a poor monsoon season last year exacerbated water scarcity.
The city could potentially resort to bringing water from distant sources, although in the long term it would not address water issues, as distant basins also deal with water scarcity. Investing in more desalination plants is also an option, with associated high costs. Aside from those, the WRI has proposed 5 measures to improve water security in Chennai:
- Harvest rainfall and use it to recharge depleted groundwater aquifers. Impervious surfaces across the city have increased as a result of fast development. It is important to provide green spaces and wetlands to allow for water infiltration; this removes standing water away from paved areas while at the same time aquifers are replenished.
- Water reuse. The discharge of untreated sewage into water bodies is a big concern. Small waste water treatment plants and decentralised waste water management, such as apartment-level systems, can treat sewage and allow it to be reused for non-potable uses in the city.
- Lake and flood plain conservation. Urban development on flood plains has made the city vulnerable to floods and drought. Authorities should discourage it and preserve these areas that absorb water during floods and also act as point of infiltration.
- Open and transparent data. Data on water resources and their uses held by the authorities should be made available to allow further research and analysis in the search for solutions to the water crisis.
- Water efficiency. As agriculture is the largest user of water resources everywhere in the world, irrigation efficiency is paramount. While efficient irrigation systems are costly, it is necessary to explore financing models and policies that will lead to further investment in this area. Rural and agricultural water use needs to be addressed in order to increase water security in Chennai and the whole state of Tamil Nadu.
The proposed measures do not only apply to Chennai but to cities around the world that struggle to ensure a regular water supply and manage floods. Across the world dry conditions and lack of proper water management combine to threat water security, now and into the future.