Amid India's drenching monsoon, Chennai's water shortage worsens

By Eric Leister, AccuWeather senior meteorologist

In this Wednesday, July 17, 2019, photo, workers fill train wagons with drinking water piped in from the Mettur dam on the Cauvery River, at Jolarpet railway station, about 216 kilometers (135 miles) from Chennai in Southern Indian state of Tamil Nadu. On its daily sojourn, the 50-tank train carries two and a half million liters of drinking water, a small but critical source for Chennai’s water board, which is employing an army of trucks to deliver 500 million liters of water a day since desiccated reservoirs and fast-diminishing groundwater forced the city to ration public tap water to millions of users for months. (AP Photo/Manish Swarup)

Monsoon downpours have overspread much of India in recent weeks bringing the country vital rainfall for water supplies and agriculture.

Meanwhile, India's southeast state of Tamil Nadu has been largely missed by any significant rainfall since the start of the yearly Southwest monsoon. Some downpours dampened northeast parts of the state, including Chennai, in late July. However, this has not been able to put more than a dent in the water shortages currently affecting the city of approximately 10 million people.

Authorities have had to take extreme action to keep water flowing to the residents of the city, including a daily train delivery of 2.5 million liters (660,000 gallons), according to the Associated Press.

The water is gathered from a dam on the Cauvery River, more than 200 km (125 miles) from Chennai, which is located on the coast of the Bay of Bengal.

A combination of rapid population growth and poor supply planning and management of the area's reservoirs was a recipe for a looming disaster.

In this Thursday, July 18, 2019, photo, a water truck carrying drinking water arrives at a locality in Chennai, in the Southern Indian state of Tamil Nadu. Demand for water in India’s Motor City, a manufacturing and IT hub on the Bay of Bengal, far outstrips supply, forcing authorities to take extreme and costly measures to deliver potable water to its residents. (AP Photo/Manish Swarup)

Below-normal monsoon rainfall during the past year became the tipping point in creating a massive water shortage for the region. The area's four major reservoirs are now nearly empty and persistent heavy rain is not expected for several months.

Satellite image showing reservoirs water levels across Chennai in June 2018. (Copernicus Sentinel-2 Satellite)

Satellite image showing depleted water levels of reservoirs around Chennai in June 2019. (Copernicus Sentinel-2 Satellite)

The above images show the sharp contrast in reservoir levels around Chennai from June 2018 to June 2019. Several of the reservoirs have completely dried up in the past 12 months.

Concerns have risen so high that water taps have only been turned on for a few hours each day since early June, according to the Associated Press.

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While most of India relies on rainfall from the Southwest monsoon to replenish water supplies, southeast India, including Chennai, often sees only sparse rainfall from June to September.

Instead, the region receives around two-thirds of its yearly rainfall during the Northeast monsoon season which occurs from October into December each year.

With near- to below-normal rainfall expected in the weeks ahead, rainfall of the magnitude needed to build up reservoir levels is not expected until late September or early October at the earliest.

Elsewhere, weeks of heavy rainfall across northern India, Bangladesh and Nepal have claimed the lives of at least 300 people, according to Reuters.

Downpours will be focused from central to western India this week with the states of Chhattisgarh, Madhya Pradesh, Gujarat and Maharashtra expecting the most widespread rainfall and highest risk for flooding.