http://localhost:8081/jspui/handle/123456789/31 2026-05-12T21:00:11Z http://localhost:8081/jspui/handle/123456789/20493 Title: DECIPHERING HYDROLOGICAL RESPONSES OF SPRINGFLOW SYSTEMS IN THE LESSER INDIAN HIMALAYAS Authors: Dass, Bhargabnanda Abstract: Springs are indispensable source of freshwater for mountain communities in the Indian Himalayan Region (IHR). These life-supporting springs are either drying up or becoming seasonal, causing hydrological imbalance in the fragile mountain watersheds due to rapid, unplanned urban growth and the mismanagement of vital natural resources resulting in water scarcity in these regions, drastically impacting the local inhabitants. Spring watershed or Springshed management, which is a transdisciplinary approach to address water security challenges for the areas that depend upon spring discharge, is essential for bolstering resilience and adaptation to water and climate vulnerabilities. But the complexity of geogenic, anthropogenic and climatic pressures together on the discharging spring aquifer besides multi-sectoral consumptive demands necessitates a comprehensive science-evidence based management optimization of spring water resources. Considering the water stress situation in the IHR there is an increasing need to understand the hydrology of Himalayan springsheds. Despite the importance of the mountain systems for regional hydrology and water supplies, the processes controlling water fluxes are not well understood; and we even poorly understand hydrologic responses connected to the region’s geology. Above all, the lack of dedicated observatories and information systems hamper improvements of the hydrologic dataset. The IHR is also highly sensitive to hydrologic variables over space and time therefore, a holistic process of understanding and high-quality reliable data from advanced field-observation techniques are necessary to understand hydrological processes. Springs which are the common sources of water for the communities in the IHR also urgently need measures to monitor the water quantity and quality to ensure water and livelihood security in the IHR. Keeping these knowledge gaps and concerns in mind a detailed investigative study which brings together the aspects of hydrology, hydrogeology, hydrogeochemistry and stable isotopic analysis has been conceptualized and executed while also integrating stakeholder welfare and participatory management in the research design. This research study investigates spring hydrological processes across three different regions in the lesser IHR in Uttarakhand, namely Almora, Pauri-Garhwal and Tehri-Garhwal. 2024-05-01T00:00:00Z http://localhost:8081/jspui/handle/123456789/20338 Title: GEOSTATISTICAL MODELLING, PLANT UPTAKE AND HUMAN HEALTH RISK ASSESSMENT OF ARSENIC IN GANGA BASIN, INDIA Authors: Dhamija, Sana Abstract: Arsenic (As) pollution has become a global concern due to its toxic and carcinogenic nature. Surface water sources are more amenable to pollution; therefore, the usage of groundwater increased rapidly. In order to ensure effective protection of groundwater sources, it is essential to take into account all geogenic and anthropogenic pollutants along with the related activities that may present a potential risk. Assessment of groundwater vulnerability to arsenic hazard may thus be considered a potentially valuable management tool for enabling major decisions on preventive groundwater protection, and there is an urgent need to develop a robust approach for the same. Groundwater vulnerability to geogenic groundwater contamination underlies the complex interplay between various intrinsic geological, hydrogeological, and geochemical characteristics in an aquifer system. Identifying the risks to groundwater quality in this regard is a very engaging process that needs to consider the source and nature of groundwater contamination from the perspective of ongoing external and internal processes within the area/region under study. Arsenic contamination in groundwater has stood out due to its worldwide spread and lethality. It is an established fact that most arsenic sources are predominantly geogenic in nature. Yet, the mechanisms of its mobilization in groundwater appear to be triggered by anthropogenic factors often. However, the propositions are still being debated and are in an ever-evolving stage. Given the above facts, the current work attempted to provide a comprehensive review of the occurrence of arsenic in the subsurface environment, along with the earlier and recent methods involved in groundwater vulnerability assessment, including mathematical, geostatistical, process-based simulation, and machine learning approaches. There are no universally applicable approaches to date, each with pros and cons. The study considered and compared available case studies and highlighted the potential of an integrated/hybrid approach to achieve the best possible outcomes. 2024-04-01T00:00:00Z http://localhost:8081/jspui/handle/123456789/20318 Title: HYDROLOGICAL DROUGHT PROPAGATION AND VULNERABILITY IN ETHIOPIA Authors: Beyene, Tegegn Kassa Abstract: In Ethiopia, precipitation variability and extremes, often associated with large-scale climate anomalies, have led to frequent devastating droughts that impact livelihoods. The major energy production of the country relies on hydropower, and frequent droughts affect energy production due to the decline of streamflow. Therefore, understanding drought severity, duration, and spatial extent is crucial to mitigating drought-related impacts. The research investigates temporal and spatial precipitation extremes and their connection to climate indices. A total of eight extreme precipitation indices were selected to investigate precipitation variability, trends and change point. Wavelet coherence and correlation coefficient were used to identify the relationship between precipitation extremes and climate indices. Most precipitation extreme indices show an increasing trend over the south and southwest regions and a change in precipitation time series between 1990 and 2012. The multiscale analysis presents strong coherence between precipitation anomaly and Nino 3.4 and IOD over the south and southeast regions. Similarly, spatial correlation shows IOD and Nino 3.4 to have a positive correlation to most precipitation extreme indices over the country's south, southwest, and southeast parts. The Northern Atlantic Oscillation (NAO) climate index negatively correlates with most precipitation extremes. We further investigated the duration, severity, and propagation time of meteorological and hydrological drought. Our results reveal that the long-term pattern of meteorological and hydrological drought is increasing in most parts of Ethiopia, with the southern part experiencing a particularly noticeable trend. The spatial analysis indicates that basin characteristics highly influence the drought propagation time from meteorological to hydrological. Highland areas take less time (1 to 6 months) to propagate from meteorological to hydrological drought compared to lowland areas, which take an extended period (9 to 12 months). Furthermore, the research examines the impact of drought on streamflow in the selected sub-basins, providing insights into the recovery period of rivers after drought events. The study investigates meteorological and hydrological drought using multiscale standardized and anomaly drought indices in four sub-basins: Ethiopia's Genale, Tekeze, Awash, and Baro basins. Two Archimedean copulas (Clayton and Gumbel) were used to identify the joint return period between drought duration and severity. We computed the streamflow required to recover from hydrological drought for selected sub-basins. Results revealed that drought frequency has increased over most sub-basins over the last two decades. Tekeze and Baro sub-basins required more than 4BCM and 2.5BCM streamflow to recover from the fifteen-month drought duration. The shortest drought duration occurred for three months in the Awash sub-basin, requiring only 0.21BCM streamflow for drought recovery. Finally, our study addresses the challenge of limited spatial data by using remote sensing and reanalysis data to assess hydrological drought vulnerability in Ethiopia. The analytical hierarchy process (AHP) is employed to assign weightage values to various influencing factors, namely, Land use/land cover, soil texture, population density, elevation, drainage density, aridity index, slope, rainfall departure, and water storage deficit index. The study results categorized hydrological drought-vulnerable areas into six categories. Most of the highly vulnerable regions are in the northeast (lower Awash) and southeast lowlands (Wabi-Shebelle and Genale-Dawa basins). The southwest (most Baro-Akobo basin) part of the country falls under low to no vulnerability zones of hydrological drought, covering only 8% of the country's area. 2023-11-01T00:00:00Z http://localhost:8081/jspui/handle/123456789/20301 Title: HYDROLOGICAL AND ENVIRONMENTAL ASSESMENT OF AN URBAN STORMWATER SYSTEM Authors: Vishwakarma, Rajesh Kumar Abstract: Over recent decades, the unprecedented pace of global urbanization has ushered in a multitude of challenges, with rapid drainage of stormwater emerging as a complex issue in burgeoning urban areas. This thesis addresses the imperative to evaluate the viability of metropolitan town stormwater drainage systems and seeks solutions to the challenges posed by urbanization. The Government of India's sub-committee for the development of "National Sustainable Habitat Parameters on Urban Stormwater Management" introduces key indices crucial for the planning, execution, and maintenance of sustainable stormwater management policies. Indices such as the Natural Drainage System Index (NDSI), Drainage Coverage Index (DCI), Permeability Index (PI), Water Bodies Rejuvenation Index (WBRI), Water Body Vulnerability Index (WBVI), Water Logging Index (WLI), Area Vulnerability Index (AWI), Stormwater Discharge Quality Index (SWDQI), and Rainfall Intensity Index (RII) were evaluated for tier-I (Delhi, Mumbai, and Chennai) and tier-II (Varanasi, Chandigarh, Roorkee) cities in India. The study employed the Analytical Hierarchy Process to rank these indices and derived an "Overall Sustainability Index" for each city, offering a nuanced understanding of their stormwater management policies. In tandem, the investigation shifts its focus to the sub-tropical urban area of Roorkee, conducting rainwater quality studies from 2016 to 2019. Results indicate alkaline precipitation events dominated by Ca2+ and HCO3-. Principal Component Analysis (PCA) and trajectory analysis shed light on ion sources and temporal variability, while the study hypothesizes anthropogenic contributions to sulphates and nitrates. 2024-06-01T00:00:00Z