Dams and barrages upstream river Indus have put paid to much of Indus delta's biodiversity. Undivided Punjab's irrigation system was established in the 1890s. In 1932, the Sukkur barrage was built reducing freshwater to the Indus delta. In 1958, the Ghulam Mohammad barrage became operative and in the early 1960s, the world's largest earth dam, Tarbela dam, was built on the Indus. These projects have rendered thousands of fisher folk, farmers and grazers jobless.

The gradual but disastrous reduction in the flow of freshwater to the delta could be gauged from the fact that the average annual and seasonal discharge downstream Kotri barrage, was 150 MAF in 1880-82. It dropped to 84.7 maf in 1940-54; 79.9 MAF in 1955-56, 46 MAF in 1955-56, and 35 MAF in 1977-92, indicating a reduction of 58.4 per cent.