Modelling impacts of climate change and socio-economic change on the Ganga, Brahmaputra, Meghna, Hooghly and Mahanadi river systems in India and Bangladesh

Abstract

The Ganga-Brahmaputra-Meghna (GBM) River System, the associated Hooghly River and the Mahanadi River System represent the largest river basins in the world serving a population of over 780 million. The rivers are of vital concern to India and Bangladesh as they provide fresh water for people, agriculture, industry, conservation and support the Delta System in the Bay of Bengal. Future changes in both climate and socio-economics have been investigated to assess whether these will alter river flows and water quality. Climate datasets downscaled from three different Global Climate Models have been used to drive a daily process based flow and water quality model. The results suggest that due to climate change the flows will increase in the monsoon period and also be enhanced in the dry season. However, once socio-economic changes are also considered, increased population, irrigation, water use and industrial development reduce water availability in drought conditions, threatening water supplies and posing a threat to river and coastal ecosystems. This study, as part of the DECCMA (Deltas, vulnerability and Climate Change: Migration and Adaptation) project, also addresses water quality issues, particularly nutrients (N and P) and their transport along the rivers and discharge into the Delta System. Climate will alter flows, increasing flood flows and changing pollution dilution factors in the rivers, as well as other key processes controlling water quality. Socio-economic change will affect water quality, as water diversion strategies, increased population and industrial development alter the water balance and enhance fluxes of nutrients from agriculture, urban centers and atmospheric deposition.

The Impact of Socio-Economic Factors on Sediment Load: A Case Study of the Yanhe River Watershed

“…Increased rural population may exacerbate soil erosion, which may affect sediment load [36]. The policy of returning farmland to forest, rapid economic development and industrial structure adjustment have profoundly changed the land use types in the basin [37,38], effectively controlled soil erosion, reduced soil erosion and improved ecological environment [39]. In this paper, Yanhe River watershed is selected as an example.…”

Water Quality Modelling of the Mekong River Basin: Climate Change and Socioeconomics Drive Flow and Nutrient Flux Changes to the Mekong Delta

“…Bangladesh (Jin et al, 2015(Jin et al, , 2018aWhitehead et al, 2015bWhitehead et al, , 2018b, as well as highly polluted rivers in Dhaka, Bangladesh (Whitehead et al, 2018a). The major applications of 191…”

“…There have been relatively few climate impact studies focused upon the Mekong River Basin that have used RCM outputs (Thuc et al, 2016). Whitehead et al (2015a) used a 25 km RCM resolution model over south Asia for the period 1971-2099, downscaled by the Met Office using the PRECIS RCM system, and applied the model to the Ganges, Brahmaputra and Meghna River Systems (Whitehead et al, 2015a(Whitehead et al, , 2018b. The RCM was based on the atmospheric component of the HadCM3 GCM (Gordon et al, 2000) with substantial modifications to the model physics (Jones et al, 2004).…”

“…The effect of high atmospheric N is to alter the terrestrial ecology of plants and natural vegetation, and provide a baseline source of N to groundwaters and streams, which can then affect aquatic ecology. Research in the Himalayas (Collins et al, 1999), in which INCA N was applied to a range of basins, suggests generally low concentrations of atmospheric N. Across India, however, levels are likely to be much higher, with greater urban and industrial sources of atmospheric N (Whitehead et al, 2018b(Whitehead et al, , 2015b. In the future, in the Mekong catchment, increased industrial development and more intensive farming methods will cause atmospheric N concentrations to increase.…”

Machine Learning to Evaluate Impacts of Flood Protection in Bangladesh, 1983–2014

“…Climate change is expected to increase the frequency and extent of extreme flood events, which will directly impact the environment and the livelihoods of people in the affected areas [1,2]. Low-lying coastal regions of the world are particularly vulnerable to these flood events and sea level rise [3,4].…”