Taunsa Wetland Pollution: Protecting the Indus River

How to read this: sentences with links are facts you can check at the source. “My view” marks my opinion. “My observation” marks something I noticed while researching. It adds newer evidence to the interactive story on Punjab’s wetlands.

A barrage that behaves like a wetland

Most of us in Punjab know Taunsa as a barrage, the gated structure that holds back the Indus and sends water into canals. Fewer know the reservoir behind it is a wetland of international importance. It was designated a Ramsar site on 22 March 1996. Ramsar is the global treaty that protects wetlands, named after the Iranian city where it was agreed. The site lies in Muzaffargarh District and was first declared a wildlife sanctuary in 1972.

I should be honest up front: this is not an untouched marsh. It is a working irrigation reservoir. My view: That makes the question sharper. Can a structure built to move water also help clean it?

How a wetland filters water

A wetland is an area of land that is kept moist enough for plants to thrive in water. Mud and silt are deposited when the velocity of water slows down in the reeds and mud. Nutrients are drawn up by plants, and some of these are mineralized by soil microbes. Ramsar’s own fact sheet says plants and soils play a significant role in purifying water. One worldwide review of wetland studies estimated that wetlands remove roughly 17% of the reactive nitrogen humans release. That is fertiliser-type nitrogen, the kind that fuels choking algae.

Taunsa has the right ingredients. Its shallow lagoons, held back by embankments, grow reeds, cattails and underwater plants.

What Taunsa gives us for free

Scientists call these benefits ecosystem services. At Taunsa they include:

• Water and food. The Ramsar information sheet describes the reservoir as a very important source of irrigation water and a working fishery. (The sheet dates from the 1990s.)
• A winter home for birds. It is a major wintering area for waterfowl, and the Indus River dolphin and smooth-coated otter are present in small numbers.
• Cleaner water downstream. The filtering described above, at least in principle.

New evidence: the filter is working, and filling up

A 2026 study sampled 300 fish plus 60 water and sediment samples from Taunsa Reservoir. Cadmium and chromium, two toxic metals, frequently exceeded permissible limits, and sediment was the main driver of metal build-up in fish. The authors’ health-risk score stayed below 1, which they read as no immediate risk, but they warn of long-term threats. It is one study of one reservoir, sampled in summer and winter, so it is a snapshot rather than a verdict.

My view: Mud that holds metals is a filter doing its job, because it keeps them from travelling on. But the study did not measure how much Taunsa removes. That reading is mine, not the authors’. And a filter that fills up eventually stops working.

Where the pollution starts

A recent policy brief from Mehran University of Engineering and Technology’s water centre says over 90% of urban and industrial wastewater is discharged untreated into the Indus and its tributaries. It also found serious metal pollution in sediments near barrages including Chashma and Taunsa, and says toxic metals concentrate when river flow is low.

Lahore is part of this chain. A paper in the Pakistan Journal of Scientific and Industrial Research notes that Lahore discharges untreated wastewater into the Ravi and cites a 1999 survey linking that pollution to a loss of 5,000 tonnes of fish a year. The same paper says up to three-quarters of the Indus flow is diverted into canals, a 1989 figure.

Wildlife shows the cost. WWF says the Indus River dolphin faces growing threats from habitat loss, pollution and changes to the river, and only about 2,000 remain. Dolphins are often treated as a sign of a healthy river, so their decline is a warning about the water itself.

At designation, the Ramsar sheet named burning of lagoon vegetation as the main threat, along with fishing disturbance, illegal hunting and a proposed upstream barrage that could lower water levels.

What protecting it would take

• Update the record. Taunsa’s Ramsar entry was last published in 1996.
• Measure regularly. The Mehran brief calls for a national monitoring framework with real-time stations at barrages.
• Treat wastewater at the source. The same brief urges new and upgraded treatment plants.
• Build filters on purpose. Gachal and Slater proposed in 2002 that effluent be diverted through planted wetland strips beside the river. The Mehran brief now recommends constructed wetlands.
• Protect the lagoons and the flow. Stop the burning, and weigh any upstream project against Taunsa’s water needs.
• Write a management plan. WWF-Pakistan will work with the Punjab government on a plan for the new Panjnad Indus River Dolphin Sanctuary, about 123 miles of river downstream of Taunsa. My view: Taunsa deserves the same attention.

What I take from all this

My observation: Reading the 2002 paper beside the 2026 study, I was struck by how little the argument has moved. Twenty-four years apart, both point to pollution at its source and wetlands built on purpose. The new sanctuary shows Punjab can act. Taunsa’s reeds have been quietly working for us all along. The least we can do is stop overloading them.