Intruding sea water threatens Indus river

Several coastal cities and towns in Sindh Province of southern Pakistan are exposed to a threat of seawater intrusion, with the Arabian Sea already having destroyed millions of acres of arable land and displaced thousands of people, government officials and experts have told IRIN. "The sea water is persistently advancing into the Indus river because of immense lack of flow from the upstream to downstream river," Mir Ali Shah, the Sindh Province irrigation minister, told IRIN in an interview. "The construction of barrages during the British rule disrupted the water flow of the Indus to a great extent, followed by more barrages afterwards," Shah added. The British, whose rule ended in the Indian subcontinent in 1947, constructed the first barrage on the Indus river in the 1930 near Sukkur, about 550 km east of the coastal city of Karachi. The barrage having proved a success, the British were prompted to erect another further downstream near Kotri, about 170 km east of Karachi. The two barrages revolutionised the region's agro-based economy, irrigating in particular the cotton-growing areas, which catered for the needs of the mills of Manchester during the post-Second World War industrial boom, and later for those of Pakistan also. However, the phenomenon also had a negative fallout: the river's water flow decreased, thereby gradually allowing sea water to encroach on the fresh. "In rivers with a long duration of high flows, fresh water is able to prevent salt water from intruding into the channel. If the volume of fresh water is large enough, fresh water can push salt water away from the river mouth," Tahir Qureshi, director of coastal ecology projects at the International Union for the Conservation of Nature (IUCN), told IRIN. Pakistan's vast irrigation system comprises three major storage reservoirs, 19 barrages or head works, 43 main canals with a conveyance length of 57,000 km, and 89,000 watercourses with a running length of more than 1.65 million km. The system irrigates more than 40 million acres of land, affording Pakistan the highest irrigated and rain-fed land ratio in the world - 4:1. This impressive irrigation is, however, taking a heavy toll. For example, Thatta, a predominantly agricultural district in Sindh Province, and situated where the Indus river flows into the Arabian Sea, has been rendered worse off. The total geographic area of the district is more than 4.29 million acres, but almost third of it has now been invaded by the sea. "About 1.2 million acres of fertile land of Thatta and adjoining areas is now directly or indirectly affected by the sea water," Shah said. The effects are not just restricted to land inundation: both mangrove forests - an essential breeding ground for shrimps - and freshwater fish species are disappearing fast. There has also been severe damage to livestock. Saltwater intrusion caused a dramatic decline in livestock numbers in all the three subdivisions of Thatta District, bringing about depletion and erosion of ranges, shortages of fodder, pasture and potable water and a resulting mass migration of inhabitants. The Sindh government’s own statistics show that 38 percent of cattle, 45 percent of buffaloes, 40 percent of sheep, 37 percent of goats, 40 percent of camels, 57 percent of horses and 35 percent of donkeys disappeared between 1991 and 2000, together with an exodus of the human population. "Thousands of people, mainly fishermen, have left their ancestral places after they were [over-] run by the Arabian Sea water," Mohammad Ali Shah, chairman of Pakistan Fisher Folk Forum said. Most of the displaced people have managed to resettle at Ibrahim Haidri, a coastal village in Karachi, and other areas. A short-term solution may be very simple: an injection of fresh water into the Indus could restore life and property. "We have got several studies, including that of IUCN, which suggest [that a] discharge of 35 million acre feet of water (MFA), 27 MFA and even 10 MFA at the delta [could help]," Shah said. But inter-provincial political differences and Islamabad’s failure to assert its regulatory role in ensuring a judicious distribution of water among the provinces are seen as underlying factors obstructing a solution. "We reached an accord during Nawaz Sharif’s last government, but we are not getting even the 10 MFA of water to push the sea back and reclaim our land," the Sindh irrigation minister complained. In order to protect its long-term economic interests, the Sindh provincial government also opposes construction of dams and other similar installations on the Indus river. Time, however, is running out. "The destruction that has so far taken place, although drastic, is still reversible. If the authorities do not ensure the flow of the required quantity of water in the Indus, things would be irreversible," Tahir Qureshi warned.