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he Indus Delta, a critical biodiversity hotspot and socio-economic hub, faces severe ecological degradation due to reduced freshwater flows and accelerating seawater intrusion.
Ecological reports, including analyses of satellite imagery from 1972 to 2017, document alarming shoreline retreat, particularly at Sir Creek, Wari Creek, Khobar Creek and Daboo Creek. This degradation threatens unique species and disrupts the livelihoods of communities in coastal districts like Thatta, Badin and Sujawal.
From its headwaters to the sea, the Indus River supports a complex web of life. Its freshwater channels, wetlands and riverine forests host a wealth of biodiversity, including the iconic Indus River dolphin. As one of the world’s rarest freshwater cetaceans, this dolphin is perfectly adapted to the turbid waters, using sophisticated echolocation to navigate and hunt.
Where the river meets the Arabian Sea, the Indus Delta’s mangrove forests take on a critical role. Acting as a natural buffer, they shield the coastline from erosion and storm surges while mitigating saline intrusion. Furthermore, these mangroves provide vital breeding grounds for fish and crustaceans, sustaining both marine populations and the fisheries that coastal communities depend upon.
The delta’s ecosystem depends on a delicate balance of freshwater and saltwater to sustain its biodiversity. The 1991 Water Apportionment Accord mandated a minimum environmental flow of 10 million acre-feet to be released downstream of Kotri Barrage to sustain the delta. However, this allocation has not been consistently met.
The Indus delta is dying because of reduced freshwater flows below Kotri Barrage. This has resulted in increased seawater intrusion, making the coastal areas less productive for agriculture and livelihoods.
Hundreds of estuaries have dried up and are being used for subsistence agriculture. New studies determining baselines for e-flows are needed to preserve the Indus.
Consultant ecologist Rafiul Haq says, “Ecological reports indicate that the delta’s annual freshwater inflow has drastically declined.” Such reduction disrupts critical ecological processes. “Freshwater transports nutrient-rich sediment, essential for mangrove growth and fish breeding,” he says.
The scarcity of riverine freshwater is crippling for local livelihoods and agriculture. Satellite imagery shows that the sea has encroached upon fertile agricultural areas by up to 54 kilometres in the creeks, causing significant land loss. Rafiul Haq notes: “Thatta, Badin and Sujawal once had rich, fertile land that supported the cultivation of red rice that was exported to Java and other destinations in Southeast Asia.” Today, farmers have been forced to shift to crops like tomatoes that have growth periods of around 45 days.
The rapid shoreline retreat at key creeks signals a system in collapse. This is not merely an environmental issue but also a direct driver of socio-economic ruin.
Climate change intensifies the delta’s ecological crisis. Reports document a 40 percent reduction in monsoon rainfall during the July, from an average of 100 mm (1960-1990) to 60 mm (1990-2015). Concurrently, temperatures from March to July have risen by approximately 1.5 C over the same period, increasing evapotranspiration and exacerbating water scarcity. These changes parch the delta, reducing freshwater availability and accelerating groundwater salinisation, which has rendered water brackish in Thatta and Sujawal unfit for drinking.
The combination of reduced rainfall and rising temperatures has disrupted the delta’s subtropical climate regulation, a process that relies on freshwater inflows to moderate sea temperatures and support mangrove and fishery ecosystems.
The delta’s decline has profound impacts. Rafiul Haq states: “Seawater intrusion has rendered millions of acres of agricultural land unproductive, forcing tens of thousands of residents in Thatta and Sujawal to abandon their villages as the sea encroaches on homes and farmlands.” The loss of arable land and freshwater resources threatens food security and livelihoods, particularly for communities dependent on agriculture and fishing. These socio-economic challenges are compounded by community displacement, creating a human tragedy alongside the ecological crisis.
The reports suggest that the Indus Delta faces an existential threat. The rapid shoreline retreat at key creeks signals a system in collapse. This is not merely an environmental issue but a direct driver of socio-economic ruin.
However, there are signs of hope through targeted restoration. “Replanting of mangroves has reversed some of damage to these plants and consequently improved fish stocks. The severity of mangrove degradation has been checked,” says Rafiul Haq. “This has managed to redress the situation somewhat, with as much as a 300 percent growth of mangroves over the last 15 years. Four out of seven mangrove species are now growing in these areas.” He adds that riverine water also reduces the pH of highly acidic seawater, promoting mangroves to flower and fruit.
Mangrove replantation and seasonal rains have provided some relief to stressed fishermen and farmers. While floods upend lives and the economy, they are also considered a blessing for the delta. Allah Yar, a farmer from Sujawal, says: “We do not get sweet drinking water and have to purchase it. The floods have helped us store water for our animals and for ourselves.” He says that river water, once available year-round, is now only accessible during the three monsoon months.
“The resurgence of mangroves has reduced our fishery losses,” says Hakeem Lashari. “Sometime back we were forced to sell small, tiny fish for poultry feed, but due to the replantation, we are able to sell grown fish. Though the absence of fresh riverine water year-round has seriously affected their growth and size.”
Ahmad Tunio highlights the social displacement, stating that most of his friends have migrated to nearby cities due to the lack of fresh water. “My brother and I found work with NGOs that need our boats for mangrove plantation. They also need manual labour. We have been gainfully employed.”
Without immediate and decisive intervention to restore freshwater flows and mitigate seawater intrusion, the delta faces an irreversible ecological breakdown, threatening both its unique biodiversity and the human communities it supports.
The writer is a senior The News staffer in Karachi.