Implications of climate change for water resources development in the Ganges basin

Abstract

This paper presents the first basin-wide assessment of the potential impact of climate change on the hydrology and production of the Ganges system, undertaken as part of the World Bank's Ganges Strategic Basin Assessment. A series of modeling efforts -downscaling of climate projections, water balance calculations, hydrological simulation and economic optimization -inform the assessment. We find that projections of precipitation across the basin, obtained from 16 Intergovernmental Panel on Climate Change-recognized General Circulation Models are highly variable, and lead to considerable differences in predictions of mean flows in the main stem of the Ganges and its tributaries. Despite uncertainties in predicted future flows, they are not, however, outside the range of natural variability in this basin, except perhaps at the tributary or sub-catchment levels. We also find that the hydropower potential associated with a set of 23 large dams in Nepal remains high across climate models, largely because annual flow in the tributary rivers greatly exceeds the storage capacities of these projects even in dry scenarios. The additional storage and smoothing of flows provided by these infrastructures translates into enhanced water availability in the dry season, but the relative value of this water for the purposes of irrigation in the Gangetic plain, and for low flow augmentation to Bangladesh under climate change, is unclear.

Reviving the Ganges water machine: potential and challenges to meet increasing water demand in the Ganges River Basin

“…The hydro-economic analysis of surface storage in the GRB by Jeuland et al (2013) highlighted that, even if much of the storage potential in Nepal is harnessed, it will have limited buffering impact on flood peaks downstream. suggested that improved groundwater management could benefit the GRB.…”

Review of hydro-economic models to address river basin management problems: structure, applications and research gaps

“…Some studies frame the latter problem as one of economic losses to downstream agriculture and ecosystems, which is attributed to the construction of dams upstream (Barbier 2003) and reservoir water release regulations (Ahrends et al 2008). Some others, however, consider the value of dam construction for reducing downstream flooding (Wu et al 2013;Jeuland et al 2013). In Australia, there has been extensive analysis of the socioeconomic and environmental implications of increasing environmental flows under alternative allocation regimes, e.g., administrative versus market-based water allocation Qureshi et al 2007;Tisdell 2010;Grafton and Jiang 2011).…”

“…, Murray River Basin (Connor et al 2009), Nilufer Basin (Gurluck and Ward 2009), and Nile Basin. Others have considered how the benefits of planned water infrastructures (e.g., dams) might be affected by the effects of climate change (Jeuland 2010;Jeuland et al 2013). Under this broad umbrella of climate change applications of HEMs, many applications consider the economic value of adaptation strategies to cope with perturbation of water supplies, via responses that include conjunctive use of surface water and groundwater (Pulido- Velázquez et al 2004Velázquez et al , 2006, adoption of more efficient irrigation technology (Ward and Pulido-Velázquez 2008;Cai and Rosegrant 2004), and new dam construction (George et al 2011a(George et al , 2011b.…”

“…Some of this work explores the sensitivity of economic outcomes to climate change (Jeuland 2010;Jeuland et al 2013). In addition, it includes a robustness analysis of different hydropower dam alternatives optimized for energy production under status quo conditions.…”

Reviving the Ganges Water Machine: potential

“…Yet, less than 1 % of that potential capacity has been developed (FAO, 2014). The hydro-economic analysis of surface storage in the Ganges River by Jeuland et al (2013) highlighted that, even if much of the storage potential of Nepal is harnessed, there is still only a limited ability to control the peak flows and floods downstream. What will benefit the Ganges River basin is an integrated water resource development plan with an improved groundwater management component, which could change the despair into joy for many millions of inhabitants .…”