A Shrinking Paddy Lake Is Watering India’s Newest Deep-Water Port

Drive inland from Kovalam for fifteen minutes and you arrive at Vellayani Lake, which looks exactly like what a visitor expects a rural Kerala lake to look like: paddy running down to still water, coconut on the ridges, a bund road, egrets, almost nobody.

What that landscape conceals is that this is not a scenic asset with an incidental water-supply function. It is a water supply with an incidental view — and the list of things drawing on it now includes the Vizhinjam International Seaport.

What the lake actually does

Vellayani is Kerala’s second largest freshwater lake and the only freshwater lake in Thiruvananthapuram district. On a coast whose famous waters — Vembanad, Ashtamudi, the Kollam and Alappuzha backwaters — are all brackish and tidal, a body of fresh water sitting in a closed basin behind the shore is a genuinely scarce thing.

It irrigates the paddy in the basin around it. It feeds the Kerala Water Authority’s local drinking-water scheme for the settlements on its banks. And it is drawn on for the supply to Vizhinjam, the deep-water transshipment terminal a few kilometres away over the ridge — the port built to intercept the container traffic that has historically been transhipped at Colombo, Singapore and Salalah rather than in India.

Why that is a heavier ask than it sounds

A port is not a village. Its water demand is continuous, contractually committed and does not fall away in a dry March. Meeting it from a shallow inland lake is a straightforward proposition only if the lake is in good condition, and Vellayani is not.

The measured story of this lake is loss. A geospatial reconstruction gives the water spread as 558.93 hectares in 1973, 267.89 hectares by 1992 and around 222 hectares by 2019. Accounts working from an earlier baseline start higher — roughly 750 hectares a century ago — and carry the series further down, to about 184 hectares by 2024. Those baselines do not agree, because different studies draw the boundary between open water, seasonal marsh and reclaimed paddy in different places, and that choice moves the figure a long way.

What no version disputes is the direction and the order of magnitude. Somewhere between half and three quarters of this lake is gone, within a period a single person could have watched.

How a lake gets smaller

Rarely by drying. Overwhelmingly by being converted at the edges. The mechanism is incremental and locally rational at every step: a shallow margin becomes seasonal marsh; seasonal marsh gets bunded for a paddy crop; the paddy plot is filled another half-metre and becomes buildable; the boundary of the lake is redrawn to where the water now reaches, and the next margin becomes the new shallow edge.

Add siltation from a catchment that has been built over, weed growth fed by fertiliser and sewage, and sand mining, and you get a lake that loses volume even faster than it loses surface — which matters more, because storage rather than area is what a dry-season supply depends on.

What is being done

The Irrigation Department began de-silting from around 2019, working to raise the lake’s mean depth by roughly 1.5 metres and recover storage for irrigation. A broader revival project reported its first phase close to completion in February 2026. Whether that is proportionate to a lake that has lost half its area, while acquiring a port as a customer, is the open question.

It is worth noting who has been keeping the records. The College of Agriculture at Vellayani — the first agricultural college in Kerala, now part of Kerala Agricultural University — sits on the bank with a 250-hectare campus, and a substantial area of the historic lake bed falls within its holdings. The reason the decline here is quantified rather than merely lamented is that the people best placed to measure it have been looking at it out of a window for decades.

What it changes for a visitor

Chiefly the etiquette, and why it is enforced. The prohibition on swimming, washing and leaving anything at Vellayani is not squeamishness about a pretty view. Everything that goes into this lake goes into a drinking supply that now reaches well beyond the villages on its shore.

And it changes what you are looking at. The wide green margins that make Vellayani so photogenic in the early light are, in part, the lake itself — converted, bunded and cropped. The view is partly a record of the loss.