Browsing by Author "Dharmaveer Singh"

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Exploring the links between variations in snow cover area and climatic variables in a Himalayan catchment using earth observations and CMIP6 climate change scenarios
(Elsevier B.V., 2022) Dharmaveer Singh; Yu Zhu; Shiyin Liu; Prashant K. Srivastava; Jaydeo K. Dharpure; Debrupa Chatterjee; Rakesh Sahu; Alexandre S. Gagnon
The spatial extent of the Snow Cover Area (SCA) of the Bhagirathi River Basin (BRB) has changed in recent decades, impacting the hydrology of the region. Previous studies examining variations in SCA in the region have yet been limited to the effects of terrain variables, namely elevation, slope and aspect, without considering the influence of climate variability. This study first investigates temporal changes in SCA and Terrestrial Water Storage (TWS) in the BRB during the period 2001–2019, which were calculated using satellite images from the Moderate Resolution Imaging Spectroradiometer (MODIS) and Gravity Recovery and Climate Experiment (GRACE), respectively, and their linkages to variation in climatic variables, and then examines how future climate change could impact on the SCA of the basin and its implications for water resources. A trend analysis revealed an increase in the SCA during the study period, correlating with an increase in precipitation and TWS over the basin. Statistically significant positive correlation were detected between the post-monsoon (r = 0.49, p < 0.05) and winter (r = 0.54, p < 0.05) SCA and precipitation, while a negative correlation was identified between SCA and Tmax during the post-monsoon (r = -0.53, p < 0.05) and winter (r = -0.69, p < 0.05) seasons. Climate change scenarios, obtained from the Coupled Model Intercomparison Project Phase 6 (CMIP6) and downscaled over the study region, project an increase in both maximum and minimum temperature, and precipitation for the pre-monsoon and winter seasons in the 2030 s under two Shared Socio-economic Pathway (SSP) greenhouse gas (GHG) emission scenarios: SSP245 and SSP585. These scenarios, together with a Multiple-Linear Regression (MLR) model developed on the basis of the relationships identified between variations in SCA and climatic variables, indicate a reduction in the SCA at 4000 + m altitudes in all seasons under both scenarios, thereby resulting a decline in the Bhagirathi river flow in spite of a projected increase in precipitation. This study demonstrates the impact of projected changes in climate on the SCA of a Himalayan catchment, and the potential implications for regions where snowmelt is important to streamflow regimes. © 2022 Elsevier B.V.
Spatiotemporal variability in stable isotopes of the Ganga River and factors affecting their distributions
(Elsevier B.V., 2021) Shive Prakash Rai; Jacob Noble; Dharmaveer Singh; Yadhvir Singh Rawat; Bhishm Kumar
Although the Ganga is an important fluvial system of India, the isotopic investigations of its water are limited and not reported for the whole length of the river. This limits the understanding of the hydrological processes of the river whose flow characteristics have been changed considerably over the years due to changes in the climate and land use/land cover patterns of the region. This study intends to fill this gap of data and knowledge. Hence, a robust isotope datasets were generated for a period of 2–3 years from 11 locations covering the entire length of the river (2250 km). These data were further analysed to study the controls on spatiotemporal patterns of river water isotopes and understand dominance of different hydrological processes affecting flow characteristics of the river in different reaches. The stable isotopes of oxygen and hydrogen in river water exhibited large spatial and temporal variation throughout the study periods. The most negative isotopic values (mean δ18O: −15‰ to −9.7‰) between 0 and 318 km in the mountainous region during pre-monsoon period attributes to the dominant glaciers melt contribution while the altitude effect in rainfall is mainly responsible during monsoon season. However, less negative isotopic values (mean δ18O: −9.7‰ to −4.3‰) between 318 and 1000 km correspond to the mixing of water from major tributaries. Other hydrological factors responsible for the increased isotopic values include evaporative enrichment and contribution of isotopically less negative groundwater. The observed relatively low isotopic values (δ18O: −4.3‰ to −6.9‰) in the downstream of 1000 km of the river are due to joining of tributaries originating from the Nepal Himalayas. Results substantiate that distinct isotopic values found in different reaches of the river are because of the variations in basin characteristics, hydro-meteorological processes, and water mixing. These findings would contribute in developing a better knowledge on hydrological behaviour of the Ganga River and help in taking appropriate measures for maintaining its sustainable flows. © 2021 Elsevier B.V.
Under Rapid Urbanisation and Climate Change Risks
(Springer Singapore, 2020) Dharmaveer Singh; Shiyin Liu; Tarun Pratap Singh; Alexandre S. Gagnon; T. Thomas; Shive Prakash Rai
There has been an exponential growth in the number of people living in urban areas since the middle of the twentieth century, and by the end of 2018, more than half of the world population lived in cities. This rapid urbanisation has created unprecedented challenges, among which the provision of domestic water has received increasing attention. Water is a basic need for humans and is the basis for socio-economic development. However, in many developing countries, governments have difficulties keeping pace with the fast rate of urbanization due to limited financial resources and a lack of technical expertise. This ultimately results in a number of water-related problems, such as the lack of provision of an adequate water supply and improper sanitation, degradation of ecosystems and stormwater management failures. Moreover, climate change is exacerbating these water-related problems by influencing the hydrological cycle. Today, there are 400 million urban dwellers worldwide affected by water scarcity and 250 million people are without improved sanitation services, causing an estimated 3.4 million deaths annually through water-borne diseases. These figures will inevitably increase, as an 80% increase in water demand is projected by 2050. According to the American Meteorological Society, accessibility to a sufficient supply of clean water is one of the critical issues facing society in the twenty-first century. Such issues are now receiving greater attention from politicians and policymakers, leading to increased research in this direction. This chapter provides insights into the problems leading to an unreliable and unsecure domestic water supply in cities and identified future water challenges that cities will face. Moreover, indicators used to measure domestic water security are explained and an index based on the amalgamation of those indicators is presented to facilitate a better understanding of urban water security. © Springer Nature Singapore Pte Ltd. 2020.