Can nature-based solutions contribute to water security in Bhopal?

Abstract

Bhojtal, a large man-made lake bordering the city of Bhopal (Madhya Pradesh state, central India), is important for the city's water supply, connoted the lifeline of the city. Despite the dry though not arid and markedly seasonal climate, soil impermeability hampers infiltration into the complex geology underlying the Bhojtal catchment. Rural communities in the catchment are nonetheless high dependent on underlying aquifers. This paper develops baseline understanding of trends in the ecology, water quality and uses of Bhojtal, discussing their implications for the long-term wellbeing of the Bhopal city region. It highlights increasing dependency on water diverted from out-of-catchment sources, and also abstraction across the Bhojtal catchment in excess of replenishment that is depressing groundwater and contributing to reported declining lake level and water quality. Despite some nature-based management initiatives, evidence suggests little progress in haltering on-going groundwater depression and declines in lake water level and quality. Significant declines in ecosystem services produced by Bhojtal are likely without intervention, a major concern given the high dependency of people in the Bhopal region on Bhojtal for their water supply and socio-economic and cultural wellbeing. Over-reliance on appropriation of water from increasingly remote sources is currently compensating for lack of attention to measures protecting or regenerating local resources that may provide greater resilience and regional self-sufficiency. Improved knowledge of catchment hydrogeology on a highly localised scale could improve the targeting and efficiency of water harvesting and other management interventions in the Bhojtal catchment, and their appropriate hybridisation with engineered solutions, protecting the catchment from unintended impacts of water extraction or increasing its carrying capacity, and also providing resilience to rising population and climate change. Ecosystem service assessment provides useful insights into the breadth of benefits of improved management of Bhojtal and its catchment.

Keywords: Catchment management; Ecosystem services; Groundwater recharge; Hydrogeology; RAWES; Water resources.