In the heart of Pakistan, Manchar Lake, the country’s largest freshwater body, is facing an existential crisis. Climate extremes and human-induced pressures have pushed this vital ecosystem to the brink, threatening not only its ecological health but also the economic stability of the surrounding regions. A groundbreaking study, led by Uzma Bhanbhro from the US Pakistan Center for Advanced Studies in Water at Mehran University of Engineering and Technology, offers a glimmer of hope, providing a practical framework for balancing water quantity and quality in arid regions.
The research, published in the journal ‘Cleaner Water’ (translated as ‘پانی صاف’), reveals that Manchar Lake’s shallow depth has led to excessive water losses, with the Water Loss Ratio (WLR) consistently exceeding 1.0. “This means the lake is losing more water than it can sustain,” explains Bhanbhro. To combat this, the study identifies critical thresholds for sustainable management, emphasizing the need to maintain a minimum area of 201.4 km² and an annual volume of 0.269 km³.
The study’s innovative approach lies in its evaluation of various management scenarios. For instance, excluding inflows from the Main Nara Valley Drain significantly improved water quality, reducing Total Dissolved Solids (TDS) levels from 4900 to 750 mg/L within two years. However, this scenario did not meet water demand. Conversely, freshwater diversion met demands but at the cost of increased TDS levels.
The most promising strategy emerged as a combination of initially excluding polluted inflows, followed by controlled freshwater diversion after the construction of Gaj Dam. This approach kept TDS levels below 1500 mg/L, acceptable for irrigation. “This integrated strategy offers a balanced approach to managing water quantity and quality,” Bhanbhro notes.
The implications of this research extend beyond Manchar Lake, offering a replicable framework for lake management in arid regions. For the energy sector, this is particularly relevant. Water is a critical resource for energy production, and ensuring its sustainable management is crucial for economic stability. As Bhanbhro puts it, “Water and energy are intrinsically linked. Sustainable water management is not just an environmental issue; it’s an economic one.”
This study underscores the need for integrated strategies that consider both water quantity and quality. It provides a roadmap for future developments in lake management, emphasizing the importance of adaptive, scenario-based approaches. As we grapple with the realities of climate change and human-induced pressures, such research is not just welcome—it’s essential.