For Ahmed Khan Jat, the unending sea intrusion has deprived the area of its agricultural diversity and prosperity in the Indus Delta. The Indus Delta, which witnessed rich farming activities in the past, has become a painful saga of brackish seawater intrusion.

From the experts’ point of view, it is primarily due to inadequate Indus River flows to check intrusion in the delta. The river is the principal source of keeping the delta’s ecology alive with consistent freshwater flows, which is no longer the case.

“Around 28 Dehs (revenue villages) have been devoured by the sea, but four are still fed by the irrigation canal although with inadequate flows for agriculture,” said Mr Jat, alluding to the Kotri barrage’s non-perennial Pinyari’s irrigation supplies amidst the chronic mismanagement of the irrigation system.

His elderly fellow, Allah Warayo, another farmer, agreed with him. “Rice has been a common crop here as climate is best suited to its cultivation,” he said.

Many villages had to relocate and much agricultural land has been lost owing to the increase of brackish water

“The delta was known for sesame and millet production. Our area used to witness ships anchoring on the coast in the colonial area, but soil erosion by seawater intrusion is permanent. We grew sesame back in 1981, but since then, my land has been barren,” he remarked.

Many farmers share similar stories about the loss of agricultural land and diversity after river flows were stored upstream in the northern plains. Sea intrusion was evident in lower Sindh’s coastal districts.

The current Sujawal and Thatta districts form a larger part of the Indus Delta, said to be the seventh largest in the world. Silt deposits that Indus used to bring in tonnes to reclaim land are a story of the past.

The Indus Delta spans around 600,000ha and gets water only during the floods season, as witnessed in 2010, 2015 and 2022, although it is prone to natural disasters, including cyclones.

A varying flow of 0.6m-0.9m cusecs had passed downstream Kotri and had some positive impact on the delta’s ecology though temporarily.

Altaf Siyal, dean of agricultural engineering faculty, Sindh Agriculture University (SAU) Tandojam, regularly works on sea intrusion. He believed the intrusion phenomenon is more pronounced in Sujawal than in Thatta.

“Land in Sujawal is flat. The mangrove population in Thatta is higher than in Sujawal, and the land is not that flat. Furthermore, wind direction in Sujawal triggers soil erosion, so Thatta has some resistance to intrusion,” he said.

Tidal floodplains in Sujawal are assessed at 0.41mha, which is double that of Thatta’s 0.2mha. “It is indicative of conversion of farmland into tidal floodplains,” he said.

Figures show Pakistan’s coastline stretches over 1,050km along the Arabian Sea. A recent Sindh irrigation department’s document on its proposed scheme of sea dyke construction in coastal parts of Thatta stated that around 80 per cent of the Indus River’s flows to the delta decreased between 1935 to 2017.

It said that the delta had 17 creeks that used to receive freshwater flows, but now the active delta is reduced to only 10pc of its original size and is further undermined by climate change phenomenon.

Seawater intrusion destroyed the coastal belt, mangroves and, above all, land loss, leading to migration. Communities keep shifting from one place to other after seawater ate up villages’ land.

“Our village [Mitho Khan Jalbani] used to be 18km away from the sea in 2018. Now it is 8km away. We can get groundwater at a depth of 25ft,” said Yaqoob Jalbani, a resident of Sujawal in union council Joigo Jalbani.

Unending sea intrusion pushed the provincial irrigation department to plan the construction of a protective dyke. The project’s cost was estimated at Rs4.52 billion, and it was to be federally funded completely.

The feasibility report was prepared in July 2021. A modified PC-I, at a revised cost of Rs4.96bn, was sent to the federal ministry for the Executive Committee of the National Economic Council’s approval.

Authenticated data regarding the loss of fertile agricultural land still eludes experts to determine the actual loss of land due to sea intrusion.

National Institute of Oceanography, in collaboration with the Pakistan Council of Research in Water Resources (PCRWR), Suparco and Pakistan Navy, lately started the project of monitoring seawater intrusion along the Pakistan coast (Balochistan/Sindh) at the cost of Rs731m in February 2021 after the release of funds.

“Data gathered in the project will become a benchmark. Digital evaluation model technique is being applied, and drone-led surveys are being conducted in the Indus Delta covering Badin, Thatta, Sujawal and Karachi,” said an official associated with the scheme.

According to a PCRWR official, the project will reveal scientific findings about salt accumulation in groundwater. “We will know whether the groundwater table is increasing,” he said. Piezometers are installed in Karachi, Thatta, Badin, Tando Mohammad Khan and even Hyderabad at different locations under the project guidelines.

Published in Dawn, The Business and Finance Weekly, April 25th, 2023