Chennai, India
#00174
Implements
#00182 Transparent emergency demand management: dashboards, escalating tariffs, pressure management and a communicated deadline
Implementer
Chennai Metropolitan Water Supply and Sewerage Board and Tamil Nadu state government
Timeline
Jun 1, 2019 – Dec 31, 2019
Location
Description
Chennai in June 2019 illustrates what happens when a megacity reaches Day Zero with no meaningful pre-crisis demand management in place. The city's four main reservoirs fell to roughly 0.1 percent of capacity. There was no established restriction ladder, no escalating tariff regime, no pressure-management program, and no transparent countdown to mobilize demand reduction in advance. The response was improvised logistics: piped supply was cut from ~830 to ~525 MLD, more than 9,000 municipal tanker trips per day were deployed, private tanker prices roughly tripled, and a dedicated water train from Jolarpettai delivered ~10 MLD at a cost of ~650 million rupees. The crisis ended when the monsoon arrived. Legacy measures included revived enforcement of the 2003 mandatory rainwater harvesting rule and desalination expansion.
Metrics
4Funding
Lessons learned
- Without a pre-existing demand-management apparatus (restriction ladder, escalating tariffs, pressure management, public data), a city at Day Zero can only improvise expensive logistics that are far less effective per rupee.
- Emergency tanker and train logistics are regressive: the poor received ~30 liters per person per day while paying the highest unit prices for water.
- A crisis resolved by rainfall rather than policy leaves the structural supply-demand gap intact for the next drought cycle.
- The water train (10 MLD at ~650 million rupees) illustrates how little volume heroic transport delivers relative to a megacity's total deficit, making the case for demand-side measures before crisis onset.