The Chotiari reservoir, located in Sindh province, Pakistan, was constructed as a water storage project to support agriculture in the region. However, a recent study conducted by the American Society of Civil Engineers (ASCE) in collaboration with experts from Pakistan has revealed significant environmental issues and sustainability challenges associated with the project.
The study, titled ‘Environmental Impact of Conversion of Natural Wetland into Reservoir: A Case Study of Chotiari Reservoir in Pakistan,’ highlighted the negative consequences of converting the Chotiari wetlands into a reservoir. It identified waterlogging, soil salinity, and adverse effects on vegetation in the surrounding areas as major concerns resulting from the project.
The Chotiari wetlands, historically consisting of deep lakes and riverine Makhi forests, possessed a rich ecosystem. There were even suggestions from wildlife conservation organizations in 2009 to consider submitting the site as a Ramsar site, which would have recognized it as an internationally significant wetland. However, this did not come to fruition.
The Chotiari reservoir was initially a complex of lakes and Makhi forests, known for its rich ecosystem. The conversion project involved raising levees on the eastern and western sides of the wetland to create a man-made water reservoir. The project, which began in 1994 and was initially intended for completion by December 1997, faced delays and alleged corruption. It was eventually finished in December 2002 at a higher cost than initially estimated. The total cost of the project escalated from an estimated Rs1.5 billion (USD 9.68 million) to Rs6 billion (USD 39 million).
The reservoir was designed to store water during the monsoon period and supply it for Rabi (winter) crops in Sanghar and Umerkot districts of Sindh. However, since its construction, the reservoir has only reached its full capacity a few times due to limited water availability. Waterlogging resulting from the reservoir has affected fertile agricultural land, converting it into unproductive salt-affected soil. Natural vegetation within the lake boundaries has also seen a decline.
Primary Objective of Chotiari Reservoir
The primary objective of the reservoir construction was to store water during the monsoon period and supply it for Rabi (winter) crops in the Sanghar and Umerkot districts of Sindh. The Chotiari reservoir, fed through the Ranto Canal, a tributary of the Nara Canal, was designed to irrigate around 290,000 acres of barren land in Sanghar’s Khipro area and neighboring Umerkot district.
However, since its construction, the Chotiari reservoir has faced challenges in reaching its full capacity due to limited water availability. It has achieved the full supply level only three times, including during a devastating countrywide flood in 2010 and subsequent torrential rains in the following years. Generally, the reservoir requires 6.5 cusecs of water per day for 70 days to reach its full capacity, but such excessive water is not readily available in the River Indus.
One of the significant findings of the study is the impact of waterlogging on agricultural land surrounding the reservoir. Since the completion of the reservoir in 2002, waterlogging has increased by 7.5 percent, leading to the conversion of approximately 4.5 percent of fertile agricultural land into unproductive, salt-affected soil. This has had a detrimental effect on agriculture, particularly cotton production, in the Sanghar district.
The study also highlights the decline in natural vegetation within the reservoir’s boundaries. Natural vegetation has decreased by up to 9 percent due to the conversion of the natural wetlands into a man-made reservoir. This loss of vegetation not only impacts the ecological balance but also has wider implications for biodiversity and environmental sustainability.
The negative consequences of the Chotiari reservoir extend beyond its immediate surroundings. Seepage from the reservoir has damaged a vast area of agricultural land in Sanghar district, which was previously a significant contributor to Pakistan’s cotton industry. The decline in cotton production in Sanghar has had implications for the country’s overall cotton exports.
The study’s findings emphasize the importance of effective planning and management in water storage and irrigation projects to mitigate negative environmental impacts. It highlights the need for sustainable approaches that consider ecological factors and long-term consequences. The Chotiari reservoir project serves as a case study, revealing the challenges associated with the conversion of natural wetlands into man-made reservoirs and emphasizing the importance of balancing development with environmental conservation.
The environmental impact of the Chotiari reservoir extends beyond its boundaries, with seepage damaging a significant area of cotton-producing agricultural land in Sanghar district. This has had implications for Pakistan’s cotton industry, as Sanghar was previously a prominent cotton-producing district but has since experienced a decline in cotton production.