Modern River Science for Watershed Management

Rivers are agents of vital flow toward sloping and geomorphic controlling systems, and there are large numbers of discharging water and sediment loads, especially in river geomorphic systems, which provide sustainable water resources for human and natural life in the modern world. The understanding of river tendencies and their perennial and non-perennial flow patterns indicates multi-dimensional conditions are segments of nature. Our research focuses on river watershed management and the essentials of river science, a wide range of river morphometrics and their dynamics, flood risk assessment, sediment load discharge, and flux measurements. One of our tasks in fulfilling the essentials of river watershed studies is to probe the human dimension of river systems in terms of river hydrological and surface processes. In addition to assessing how river systems change through natural and anthropogenic activity, climate change affects the linkages between them. The sources of anthropogenic pollution from excessive use of industrial effluents are included in this book. In order to attain an in-depth understanding of river science, we aimed to provide the research community with novel developments in watershed management through applications of geographical information systems, remote sensing, and artificial intelligence approaches in an accurate and understandable manner. The field of water resource management has benefited from advances in scientific knowledge, GIS technology for watershed development, and the application of hydrogeological perspectives. The most recent methods in GIS as they apply to groundwater potential are compiled by using geospatial techniques for watershed management. As a result, this book will assist readers in discovering, in a single volume, the most recent developments in geospatial techniques and their hydrogeological applications.

The present research has estimated surface runoff and measured the stimulated hydrological response at the ungauged watershed boundary of the Hasdeo River. The watershed boundary of Hasdeo river basin covers an area of around 9633 km². The coalfields, namely Mand-Raigarh, Chirimiri, Hasdo-Arand, Korba, Sendurgarh and Sohagpur coalfield (eastern part) falls inside the Hasdeo watershed boundary. These coalfields have active coal mines and play a significant role in the country’s coal production. The physically based semi-distributed soil and water assessment tool model (SWAT) has been used to model the hydrological processes in the Hasdeo river watershed basin. The watershed outlet has been taken near Deoraha village, which falls in the Janjgir–Champa district of Chhattisgarh state. Calibration and validation of the model have been done by splitting the observed discharge data into two datasets in the SWAT model. The calibration has been done for the period 1994–2008 and validated for the period 2009–2018 on a monthly basis. The flow output has been calibrated using the SUFI-2 algorithm approach in SWAT-CUP. The p-factor and r-factor values for the calibration and validation periods obtained at Deoraha are 0.96, 1.68 and 0.96, 2.69, respectively. The performance of the SWAT model has been statistically assessed using the coefficient of determination value (R²), Nash–Sutcliff efficiency value (NSE) and percent of bias (PBIAS). The coefficient of determination value (R²) was 0.76 and 0.75, Nash and Sutcliffe efficiency value (NSE) was 0.75 and 0.70 for the calibrated and validated periods, respectively, which indicates that the results obtained are satisfactory. Similarly, the percent bias (PBIAS) value for the calibrated and validated models was − 6.2 and − 7.8, respectively. Based on the results obtained for stimulated and observed flow, it can be concluded that these results can be used to develop sustainable water management and development in the Hasdeo river watershed boundary.

This research focuses on the calculation of rainfall discharge and hydrological analysis in the Gadi Gedda Watershed, situated in the Vizianagaram District of Andhra Pradesh, India. The watershed area has notable challenges in water management because of its intricate geography and unpredictable patterns of rainfall. To address these challenges, a comprehensive approach was adopted, which included the integration of Remote Sensing (RS) and Geographic Information System (GIS) methodologies. The collection and processing of satellite-derived precipitation data, hydrological parameters, and land cover information were conducted using RS and GIS technologies. This approach enabled the development of precise rainfall-runoff models and the understanding of hydrological processes within the watershed. Furthermore, the use of high-resolution satellite data played a crucial role in the categorisation of land cover, facilitating the discernment of several land use classifications within the catchment area. The estimation of the rainfall-runoff relationship in the study region was conducted using the SCS-CN approach. The model underwent calibration and validation processes to assure the reliability and accuracy of the simulation findings, using HSG soils, land use/land cover analyses, and rainfall data. The results of this research provide valuable insights into the hydrological dynamics of the Gadi Gedda Watershed and shed light on the impact of changes in land use on flow patterns. Furthermore, this research assesses the potential of RS and GIS methods in the field of water resource management. It also establishes the foundation for implementing sustainable water management practices in the specific location. The study enhances our understanding of the complex interplay of precipitation, outflow, and land use within the Gadi Gedda Watershed. The integration of RS and GIS methodologies in hydrological research may be used to similar watersheds facing similar issues, therefore facilitating efficient water resource management and enhancing the resilience of populations in locations with limited water availability.

Changes in hydrology of the basin due to anthropogenic and changing climatic conditions affect the management of water in industrial, domestic and agricultural practices. So focus should be given on hydrological research to assess and predict the discharge from a watershed. Calculating discharge from a watershed would help the engineers and urban planners to manage and distribute the river water effectively. Using Soil Water Assessment Tool (SWAT), discharge from each outlet of the sub-watershed is calculated based on soil, climate and LULC conditions. The SWAT model results help in identifying micro-watersheds based on HRU analysis. Further, it helps in identifying the points for the gauge stations to monitor water discharge from each micro-watershed. Forming of these micro-watersheds and gauge stations in a sub-watershed helps the urban planners, engineers and stakeholders to administer river water discharge for various uses in a drainage basin.

Hydrology, the science of water movement through the Earth’s surface and subsurface, stands at the crossroads of two pivotal forces reshaping our planet: climate change and anthropogenic activities. The intricate relationship between climate and anthropogenic activities significantly affects hydrology, influencing the availability and distribution of freshwater resources worldwide. Climate change, driven by greenhouse gas emissions, is causing alterations in precipitation patterns, temperature regimes, and the melting of glaciers, leading to shifts in hydrological cycles. Simultaneously, human activities like urban expansion, deforestation, and agriculture are altering land use and land cover, resulting in shifts in surface runoff, groundwater replenishment, and water quality. The cumulative result of these climate and anthropogenic influences on hydrology transcends environmental concerns. It affects agricultural productivity, drinking water availability, energy production, water resource management, ecological sustainability, resilience of ecosystems, and human safety. Ecological systems are strained, aquatic habitats deteriorate, and the risk of waterborne diseases surges. Mitigating these repercussions necessitates a holistic approach rooted in a deep understanding of the intricate interplay between climate and human-induced changes in hydrology. The soil and water assessment tool (SWAT) was used to analyze the combined effect of climate and anthropogenic activities in the streamflow. Understanding the complex interplay between climate dynamics and human interventions is crucial for devising adaptive strategies to mitigate the adverse repercussions on hydrology and foster sustainable water management practices in the face of these evolving challenges.

An extensive geomorphological investigation was undertaken in the Belan River drainage basin, a significant tributary of the central Indian Tons River. The course of the Belan River closely follows the regional strike trend of the Vindhyan Supergroup rocks within the Son Valley. Notably, the river's drainage patterns exhibit a polymodal distribution, with distinct NW–SE and N–S trends being particularly prominent in the basin. The presence of knick points further substantiates subsurface deformation, while the basin's tilt, as determined through the asymmetry factor and evident in the longitudinal river profiles, indicates ongoing slope adjustments. This study adopts a primarily quantitative approach to comprehensively develop the Belan River watershed. Notably, the Belan River and its tributaries hold historical significance as early human settlement sites. Groundwater, a vital resource for both drinking and irrigation, primarily originates from surface rainwater or shallow-dug wells. These wells are predominantly located in small pockets of alluvium or regions characterized by highly fractured/jointed rocks. This research marks a noteworthy advancement in applying quantitative methodologies for effective drainage management and exploring groundwater potential, thereby significantly contributing to the holistic watershed development of the Belan River basin.

This book chapter presents a complete approach to morphometric analysis of the Gadi Gedda watershed located in the Vizianagaram district of Andhra Pradesh, India. The study integrates remote sensing (RS) and geographic information system (GIS) techniques to assess the morphometric characteristics of the watershed. The main objectives of this study were to determine various morphometric parameters and analyse their spatial distribution within the watershed. The RS data utilized in this research included high-resolution satellite imagery and digital elevation models (DEM). The image was processed and classified to identify land cover information, which was further utilized for identifying distinct classes within the watershed. The DEM data were processed to extract various morphometric parameters, including drainage network, watershed boundaries, stream order, stream length, and slope. The GIS platform facilitated the integration and analysis of the RS data. The morphometric parameters were computed using GIS tools, and their spatial distribution was visualized using thematic maps. Furthermore, statistical analysis was conducted to quantify the morphometric characteristics and assess their relationships. The results of the study revealed significant variations in morphometric parameters within the Gadi Gedda watershed. The drainage network had hierarchical patterns, with variations in stream orders and lengths. The watershed had varying degrees of elongation, indicating its shape. Additionally, slope analysis indicated variations in terrain steepness and the potential for surface runoff. The integrated approach of RS and GIS proved to be highly effective in conducting a comprehensive morphometric analysis of the Gadi Gedda watershed. The findings provide valuable insights into the watershed's hydrological behaviour, which can aid in land and water resource management, flood mitigation, and sustainable development planning. This study serves as a reference for future research endeavours aimed at understanding and managing watersheds using RS and GIS techniques.

An essential tool for examining drainage networks, exploring geomorphological characteristics, and connecting them to future basin management plans is remote sensing technology based on satellites. The linear, aerial, and relief features of the geomorphologic development and river basin's potential for groundwater are evaluated quantitatively using morphometric analysis. In this paper, an attempt was made to investigate the specific morphometric features of the Chinnar sub-basin. Here, 56 morphometric parameters across all dimensions have been computed. One of the main tributaries of the Cauvery River, the Chinnar sub-basin flows through the Dharmapuri District in Tamil Nadu, India. The drainage network, basin geometry, texture analysis, and terrain features have all been covered in the quantitative morphometric analysis (QMA) of the Chinnar sub-basin. The Strahler classification method was utilized to describe the drainage network, and the results suggest that the topography displays drainage patterns including dendritic, parallel, radial, and trellis. The research region was classified as seventh-order, and lower-order streams predominate there, which is a key contributor to flash floods. The average bifurcation ratio shows that there were several structural disturbances in the area. The Chinnar sub-basin covers 1539.784 km² in total. The Chinnar sub-basin's elongation ratio is 0.449, and its circularity ratio is 0.255, indicating that the basin has an elongated form. With 2.407 km/km², the research area’s drainage density is high. The calculated value of 21.738 demonstrates the basin’s fine drainage texture. The basin is made up of low-erodible rocks and requires a minimum area of 0.415 km² to develop a channel. The south-western section has a strong slope, as shown by the basin slope, which runs from 0° to 58°. The sub-basin's relief ratio indicates that both pediplain and hilly zones are involved. Several themed maps, including those for drainage density, relief, contour, slope, and aspect, were produced using the ArcGIS software. QMA is essential to controlling the drainage basin. The study comes to a conclusion by analyzing the findings of QMA parameters and thematic data to comprehend the geomorphological issues and the sustainable development of water resources in the Chinnar sub-basin.

The current research emphasizes the advantages of employing geospatial techniques to deduce hydrological insights for the management of the water resource in the Thutapuzha sub-basin (TSB), a major tributary of the Bharathapuzha, the major river in Kerala, India. For this study, ASTER DEM is utilized within the ArcGIS software to extract essential morphometric parameters specific to the Thutapuzha sub-basin (TSB). Morphometric parameters serve as crucial and systematic tools for evaluating water resources within a river basin. Morphometric parameters coming under linear aspects, areal aspects, and relief aspects are computed for the TSB, and their hydrological implications are thoroughly examined. The dataset generated from morphometric parameters suggests that the basin exhibits promising potential for water resource management and offers scientific insights for flood management initiatives within the basin. The TSB, as a sixth-order basin with dendritic and sub-dendritic patterns, features a significant number of high-order streams, indicative of significant discharge of water, and a low flow rate, highlighting that the basin is susceptible to flood hazards. Furthermore, the areal morphometric characteristics of TSB also point to substantial water discharge and peak flow occurring within a relatively short time frame. This study demonstrates that SRTM-DEM-based hydrological assessments at the sub-basin level prove to be more practical and accurate when compared to alternative techniques. The resulting database provides valuable scientific information for the management of water resources.

Hydrogeology and GIS integration mark a transformative era in managing Earth’s vital water resources. This chapter explores their synergy, emphasizing GIS tools for precision in groundwater exploration and monitoring. GIS, a bridge between spatial data and analysis, plays a crucial role in hydrogeological research, addressing challenges like contamination and sustainable water resource management. Its applications span spatial analysis, groundwater modeling, resource assessment, emergency response, and more. GIS's dynamic evolution offers hope for informed decisions and sustainable water resource utilization. Comprehensive data collection methods, including field surveys and satellite imagery, are explored, emphasizing structured databases and effective data management. GIS’s pivotal role in creating maps and visualizations for hydrogeological datas are highlighted, showcasing spatial analysis, buffer analysis, overlay analysis, and time-series analysis. Time-series analysis, exemplified by Vamanapuram dug wells, illustrates dynamic patterns, revealing seasonal influences and prompting further analysis for effective water management. Water quality zonation using GIS involves gathering spatially referenced data, thematic layer generation, overlay analysis, and creating zones. Challenges in overlay analysis are addressed, emphasizing data quality and normalization using AHP for complex decision-making. River basin studies and GIS integration highlight GIS's role in watershed delineation, flow pattern calculation, and environmental impact assessments. DEMs, crucial for hydrological modeling, floodplain mapping, and infrastructure planning, contribute to precise topographic information. The physiography map of South India, categorized by elevation ranges using DEM data, aids resource management, environmental planning, and disaster risk assessment.

This study delves into the application of remote sensing and GIS in river-related research. Its primary aims are twofold: firstly, to identify the diverse disciplines within river-related studies employing remote sensing and GIS, and secondly, to scrutinize the methodologies employed in these studies. A total of sixty-nine research papers, delineating twelve distinct disciplines within remote sensing and GIS related to river studies were reviewed and identified, respectively. The predominant remote sensing data utilized includes Landsat imagery, digital elevation models, and Sentinel data. Extracted information encompasses land use and land cover, vegetation indices, river dimensions, sinuosity, drainage networks, morphometric parameters, slope, flow accumulation, elevation differentials, and topographic features. All remote sensing data extraction processes are conducted within the GIS framework. Additionally, the studies address the limitations associated with remote sensing data in this context. Furthermore, this comprehensive overview of the current landscape of river-related research utilizing remote sensing and GIS, providing researchers with a clear understanding of the existing body of knowledge.

This research article reflects the use of an integrated approach of geospatial and social sciences for the planning and management of micro watersheds in Dharampur Block, Himachal Pradesh. The micro-watershed area had many problems related to soil erosion, scarcity of water sources during the summer season, and unsustainable livelihood options. These problems were identified through the field survey and presented through the geospatial sciences. In the initial stage of watershed development, the plan was implemented to solve the problems of soil erosion, water scarcity through check dams and spring shed management, and the revival of natural water sources. The sustainable livelihood problem tries to be solved by uplifting agriculture and horticulture and linking people with microenterprises such as beekeeping, poultry, and dairy. The weaker sections and communities of the micro watershed were the targeted groups under the section of water social and economic development. The project implementation period starts in 2022 and ends in 2027, and its results shall be evaluated after the completion of this project.

A separated buried river channel from the active river by the activities of cutoff or abandonment is called paleochannels and later they may be filled with the sediments of young unconsolidated or semi-consolidated. Additionally, it is impacted by geomorphological influences, lineament alterations, and other factors. The aim of this study is to identify the paleochannels in Periyar River Basin for the year 2023. Those channels have high probability in the presence of natural resources including gold, platinum, tin, and uranium. Numerous techniques are used to map the paleochannel. Using the optical data, satellite images were collected from various sources which comprise multispectral satellite images from which indices such as normalized difference vegetation index (NDVI), normalized difference water index (NDWI), soil adjusted vegetative index (SAVI) and thematic layers, such as lithology, stream network, and lineament were prepared. Weights are assigned to each layer based on its importance and overlay analysis has been done which concluded that the northwest region of the area has shown some paleochannel patterns. The results were cross-verified using the results obtained using microwave data. Using Sentinel data, SAR Image was extracted from ESA portal, preprocessed it using SNAP 6.0. In addition to that, polarimetric decomposition technique has been incorporated to detect the paleochannels based on its scattering property. Further, principal component analysis has been done for enhanced output imagery. Results obtained from optical and microwave radar data were compared and the location of paleochannels was detected. Six paleochannels in the study area were identified out of which three paleochannels were validated with the existing data published by Department of Geology and Environmental Science, Kerala. The other three paleochannels were newly detected with the help of SARimage.

Rivers and water bodies have always been the pillars of civilization and meet all the needs of humans and animals. The present study focuses on the Water Provisioning Services (WPS) of various water reservoirs in the Indian state of Chhattisgarh. The present paper provides an overview of the WPS of the ten major reservoirs constructed in the Mahanadi River Basin (MRB) in the central Indian state of Chhattisgarh. The Minimata Hasdeo Bango Dam of Korba districts tops the list with the largest catchment area (6730 km²), live capacity (2894 MCM) and full reservoir level (395.66 m). It fulfills the demand of domestic water to the entire Korba town, supplies 441 MCM water for industrial needs to major industries (BALCO, NTPC, SECL, BPCL, etc.), irrigates about 433,500 ha of agricultural land area and is also one of the important recreational and tourist destinations of the state. Hydropower generation from Chhattigarh’s reservoirs is 127 MW, of which 120 MW comes from Minimata Hasdeo Bango Dam and about 7 MW from Sikasar Dam. The economic assessment of runoff retention of the different land use types of the study area shows that forests help in runoff retention worth Rs 247.26 crore annually, while net sown agricultural area contributes to Rs 170.93 crore annually. The present paper will provide a database for further research in this area and also contribute to the conservation of the reservoirs. It will also help policymakers, land use planners, academicians, etc. for proper land use planning, management, monitoring, implementation and adaptation to climate change.

Climate change has long-term impacts on precipitation patterns, magnitude, and intensity, affecting regional water resources availability. Besides, understanding the interannual to decadal variations of streamflows in a river basin is paramount for watershed management, primarily extreme events such as floods and droughts. This study investigates impact of climate change in streamflows estimation for four sub-basins of the Mahanadi River, in India. The study includes three major components: (i) Historical trend analysis of hydroclimatic variables, using Mann–Kendall test; (ii) Statistical downscaling of GCM generated precipitation using change factor method and KnnCAD V4 stochastic weather generator; (iii) Dependable flow analysis of future streamflows predicted using Soil Water Assessment Tool (SWAT) model for various future GCM scenarios. It is observed that during the historical period, there is a decrease in number of rainy days and total annual precipitation in all sub-basins. However, the analysis also indicates an increase in flood intensity in two of the sub-basins. The decadal future precipitation has a marginal decrease in precipitation (up to 10%) for future scenarios; however, the precipitation events with high intensities increase. The results indicate that the magnitudes of 5 and 10% dependable flows are higher than the historically observed streamflows, for all future scenarios. This indicates a significant increase in extreme flood events in the basin. Further, only one of the sub-basins has shown an increase in water availability for agriculture and drinking water purposes (75 and 95% dependable flows) in the future. Understanding future flood events in the Mahanadi basin can help decision-makers to implement appropriate mitigation strategies.

Hypsometric analysis is a powerful tool in identifying geomorphic stages and erosion status of a river basin. This study focuses on conducting hypsometric analyses on two prominent river basins in southern India, the Bharathapuzha River basin (BRB) and the Chaliyar River basin (CRB). The primary aim is to assess the erosion status of these basins by dividing them into sub-watersheds and analyzing the hypsometric parameters of each. The BRB was subdivided into 15 sub-watersheds, and we conducted individual hypsometric analyses for each of them. Among these sub-watersheds, W6, W8, W9, and W10 (eastern part of BRB) were identified as highly vulnerable to erosion. In the case of the CRB, hypsometric analysis indicated that 4 sub-watersheds are in mature stage and remaining in old stage. The four sub-watersheds in mature stage are susceptible to soil erosion when compared to others. This approach would also aid in the development of guidelines for managing soil, land, and water resources on a watershed level.

In the Anthropocene era, the fresh water resources deserve high importance due to various demands and hence its management and protection are very important. In the present work, the comparative study of the water quality of Kabini River in Kerala and Karnataka state has been made and data is subjected to principal component analysis (PCA) in order to understand the prominent sources of major ions along the region. In Kerala state, the surface water quality of Kabini basin falls in potable category, whereas the Karnataka region demarcates highly distress environmental conditions and unsuitability in terms of direct consumption. The constrains in potability in region is mostly influenced by man-made activities and natural processes. The PCA in Kerala demonstrated the weathering of nearby rocks and heavy usage of pesticides, whereas in Karnataka demonstrated rock–water interactions as well as industrial expansions and agricultural activities. The data generated from the present work would be useful for future decision makers to manage the issues in a holistic manner and can derive suitable steps for the management of the river basin both in Kerala and Karnataka states.

Unsustainable depletion of groundwater resources is increasingly evident and poses a significant concern for numerous developing nations. India, in particular, faces a severe water scarcity problem due to its rapidly expanding population, resulting in the encroachment of natural resources and disruption of hydrological processes. Consequently, essential surface water bodies are progressively vanishing, placing greater stress on groundwater reserves. The work was carried out in the Pullamapatti watershed in northern Tamil Nadu to delineate areas with groundwater potential. A multi-criteria approach, incorporating RS and GIS, was employed for this analysis. Seven parameters, viz., geomorphology, slope, lineament density, drainage density, soil composition, lithology, and land use/land cover (LULC), were utilized to find out groundwater potential zones (GWPZs). The resulting maps categorized these zones into low, moderate, and high-potential areas. The majority of the Pullamapatti watershed (84.9%) falls into the intermediate potential category.

The main objectives of this study are to find out the aquifer thickness and characterization of the aquifer by using geo-electrical resistivity Schlumberger’s technique in the lower Tamirabarani River Basin, Tamil Nadu, India. The electrical resistivity method, viz. Schlumberger configuration (48 VES Survey), was conducted using equal grid intersection points. The primary field data was interpreted using the manual curve-matching method at the field. Subsequently, geo-electrical sounding data can be calculated and analysed digitally by using the IPI2WIN software. The nine 2D profiles were prepared using IPIWIN software. Apart from that, VES up to 100 m depth categorises five subsurface resistivity layers. As a result of seawater seeping into the groundwater, small areas of less than 10 Ωm were found along the coastal track along the seashore villages like Palayakal, Kayalpattinam, Tiruchchendur, and Perungalam. The shallow depth (3.5–30 m of aquifer) of groundwater quality is affected by seawater intrusion.

In future, many sectors will depend on artificial intelligence (AI) play a key role in the smart identification of water resources. Gathering of diverse primary and secondary data about water resources, which will be analyzed by automatic machine learning. This kind of water resource potential and pollution model can be characterized by AI tools. The availability of hydrological data, such as for optimizing irrigation schemes, predicting floods and droughts, monitoring water quality, managing dams, managing water supply, and modeling contaminant transport, among others, provides an ideal condition to create AI that allows us to expand our existing knowledge to manage water resources. Artificial intelligence has enabled the creation of intelligent machine-learning training datasets to solve the problems of water resource management. This artificial intelligence study shows water resource potential problems and further improvement techniques. AI-based water network management provides an understanding of the tools to be developed in the field of hydrology and hydrogeology for quick identification of suspect problems. This program predicts water quality and quantity according to decision-making processes. Integrate the knowledge and skills needed to assess the impact on water resource planning and management due to population growth, climate change, and land use changes. Overall, data-driven and AI tools for water resources support decision-making for effective sustainable water resource management. This study is an attempt to present a review of the application of AI in water resource management in watersheds for planning, modeling, prediction-based decision systems, forecasting, decision support frameworks, and optimization.

The geology and hydrogeology of a study area primarily exert control over groundwater recharge and reserves, groundwater chemistry, suitability for various purposes, weathering processes in rocks and soils, as well as geochemical processes in groundwater. Establishing connections among these factors is crucial for gaining a comprehensive understanding of the groundwater regime. As such, the Chithar River basin, situated between latitudes 08° 48′ N–09° 14′ N and longitudes 77° 11′ N–77° 46′ E in Tirunelveli District, Tamil Nadu, India, has been selected for an integrated analysis of the aforementioned parameters. Examinations of the rock and soil composition reveal that the charnockites in this area are notably rich in quartz, plagioclase feldspars, and orthopyroxenes. Meanwhile, gneissic rocks in the region exhibit an abundance of potash feldspars and albite. Additionally, the limestone found here contains a higher concentration of mafic minerals, giving it a dolomitic characteristic. The weathering processes affecting soda feldspar (albite) and potash feldspars (orthoclase and microcline), which are prevalent in the biotite gneiss within the study area, significantly contribute Na⁺ and K⁺ ions to the groundwater. Similarly, calcic-plagioclase feldspars, pyroxenes, and amphiboles, commonly found in the silicate rocks of the study area, play a substantial role in introducing Ca²⁺ and Mg²⁺ ions into the groundwater through weathering processes.

This research work focused at the connections between ground water quality and the healthiness associated with drinking of contaminated water in the Kodavanar River Basin. Totally sixty samples were collected from river basin to know various elements like pH, alkalinity, TH, TDS, EC, Fe, Na, Ca, Mg, K, HCO₃, NO₃, Cl, SO₄², F, etc., to compare with WHO standard to measure the groundwater quality for domestic usage via entropy water quality index (EWQI). Based on EWQI it is observed that 50% of samples fell into the “good” class and 50% of samples fell into the poor class for consumption purpose. The results subjected into piper plot reveals that significant portion of the research field has the mixed Ca²⁺–Mg²⁺–Cl⁻ water type during all seasons. The spatial exposure of nitrate contaminated groundwater in around 1576 km² in all the seasons shows that 1502 and 986 km² fell into the health risk zone for both children and adults correspondingly. Similarly, the spatial analysis of sum of dermal and oral exposure of fluoride-contaminated groundwater zone identified around 1390 km² in all the seasons, which exposes 1401 km² and 744 km² identified health threat region for children and adults, respectively, in all the seasons like winter, summer, post-monsoon, and pre-monsoon. This study reveals the essentials for workable management of underground water in the region under study and advanced treatment methods such as reverse osmosis, membrane filtration techniques to be adopted to remediate the contaminated ground water in this area.

Current study assesses multidecal hydrochemical data of the Cauvery river basin (CRB) to understand spatio-temporal variations, hydrogeochemical facies, irrigation water quality, solute sources, and controlling mechanisms along with statistical analysis and pCO₂ estmations. The data used for this study are surface water quality data of CRB for years 1990–2016 on monthly basis. Spatial varations indiacte solutes in downstreams are several times higher than upstreams suggests influence of climatic conditions like sub-humid upstream to semi-arid downstream and anthropogenic activities. Temporal analysis reveals solute concentrations follow the order; pre-monsoon > post-monsoon > monsoon throughout basin suggests control of monsoonal climate in the basin like high precipitation in monsoon season (June–November) resulting in dilution while high temperatures during pre-monsoon season (March–May) leading to evaporation. Gibbs diagram suggests principal solute load regulating mechanism of CRB is water–rock/soil interaction i.e., chemical alteration (weathering) of minerals. The HCO3 normalized Na + K versus Ca + Mg diagram reveals the role of anthropogenic activities and are asserted by scatter plot of Na versus Cl. Further, the correlations and principal component analyses of multidecadal data evince that, chemical weathering follows anthropogenic and atmospheric inputs as the primary mechanism for acquiring solutes in CRB. The irrigation water quality index for year 2016 indicate most of the samples have low and no restriction to irrigational usage. Estimated aqueous pressure of CO₂ (pCO₂) of CRB waters are higher than the atmospheric pCO₂ irrespective of season throughout the basin and an observed decreasing trend of pCO₂ with respect to pH signify the extreme chemical weathering nature of the basin.

A study investigates characteristics of sediment textures, magnetic susceptibility (χlf), frequency dependence (χfd%), and mineral assemblages at selected five core samples collected from Uppanar estuary, Cauvery estuary, Nandalar estuary, Arasalar estuary, and Vettar estuary along the east coast of Tamil Nadu, Bay of Bengal. To establish the textural characteristics, an analysis of grain size distribution was performed (mean size, sorting, skewness and kurtosis) and its hydrodynamic energy conditions; the magnetic susceptibility (χlf) profile quantifies the magnetic components; and mineral assemblage unveils the magnetic minerals of the sediment transport and accumulation characteristics at different depths of different river estuaries. The anticipated findings is worth to notice the hydrodynamic energy plots reveals the Uppanar, Cauvery, and Arasalar core profile shows an higher energy environment conditions, which is higher than the Nandalar and Vettar core sediment estuary, it suggests an higher composition of sand and silt content of the percentage of grains distribution in the sediments. The magnetic susceptibility of (χlf) profile shows Uppanar core samples showing 41.96 × 10^–6 m³/kg to 94.34 × 10^–6 m³/kg, with an average of 54.48 × 10^–6 m³/kg; the Cauvery core samples displays 7.13 × 10^–6 m³/kg to 157.39 × 10^–6 m³/kg, with an average of 44.25 × 10^–6 m³/kg; the Arasalar core displays 8.67 × 10^–6 m³/kg to 196.57 × 10^–6 m³/kg, with an average of 45.96 × 10^–6 m³/kg. While the magnetic susceptibility value of Nandalar core is showing an 5.67 × 10^–6 m³/kg to 33.67 × 10^–6 m³/kg with an average of 13.01 × 10^–6 m³/kg; and Vettar core indicates 15.77 × 10^–6 m³/kg to 279.13 × 10^–6 m³/kg with an average of 127.78 × 10^–6 m³/kg, which is higher than that of Uppanar, Cauvery, and Arasalar estuary, it suggests an higher components of ferromagnetic minerals in the sediments. In five different cores, the sand, silt, and clay particles shows significant correlation with the low magnetic frequency (χlf), which infers that the size of the magnetic minerals are directly related to grain sizes. The magnetic mineral assemblages and sediment textures indicates the Uppanar, Cauvery core sediments having magnetite minerals, the Nandalar, and Vettar core sediments indicates maghemite, while Arasalar core sediments comprised of hematite minerals due to oxidization process, the magnetite converts to hematite in the estuarine river sediments accumulations. The χlf/fd value shows the magnetic sediment trap zones at a particular depth of all the core profile in the river estuaries. Therefore, the findings of this study suggest that relation of hydrodynamic characteristics and environmental magnetic studies can possibly applied as an efficient way for monitoring and assessing the sediments nature on a qualitative level.

This article presents geochemical characteristics of sediment and water samples of Musi River in part of Hyderabad city. The Musi River was once upon a time known as the ‘lifeline of twin cities’ as a primary drinking water source, now turned to a sewerage channel. Earlier workers have focussed on water quality, chemistry of soils in the proximal crop fields and groundwater quality on the banks of the river. Therefore, an attempt is made in this investigation to study chemistry of sediments along with that of the water. The sediment samples were analysed for granulometry (n = 9) as well as major oxides and trace element concentrations (n = 14). The water samples (n = 22) were analysed for physico-chemical characteristics. It is observed that the sediments as well as waters are heavily contaminated with objectionable odour overloaded with domestic waste. The sediments are very lepto kurtic (1.99–21.11) and very finely skewed (0.78–3.8) indicating high energy or agitative environment. The sediments are black in colour due to excessive content of organic matter. High concentrations of SiO₂ (50–60 wt%), Al₂O₃ (8–13wt%) and P₂O₅ (1745–20,167 wt%) indicate heavy industrial and agricultural contamination. The sediments are enriched in trace elements such as Li, Cu, Cr, V, Ni, Zr, Zn, and Pb, which are harmful for biota. The heavily contaminated waters of Musi within the city limits are of mixed type with unpleasant odour and are unsuitable for irrigation. The domestic sewerage occupies 5.3% of total influx while the major part comes out from industrial effluents. As a whole, the Musi River, within Hyderabad city limits, already reached a stage where its water quality cannot be repaired and restored.

The current study evaluated the extent of heavy metal concentrations in the bulk sediment samples of Neyyar River, a perennial river originating from the Western Ghats and flowing through the extreme south of Kerala State. In contrast to other rivers in India, Kerala rivers are very small and are severely degraded due to various types of human interventions. Mining for sand from river beds and banks, dumping of wastes, discharges from industrial and agricultural activities, etc., has imparted tremendous degradation in terms of weakening of river bank stability, modification of soil–water balance, pollution, structural loss of exposed riverine sediments, and change in normal river bed characteristics. The pollution status of the riverine systems can be well understood by analyzing the recent sediments. Hence, the evaluation of sediment pollution was conducted in Neyyar River using contaminant geochemical indices in the bulk sediment samples from 17 locations collected during Pre-Monsoon (PrMon), Monsoon (Mon), and Post-Monsoon (PoMon) seasons. The results suggested that the contamination factor (CNF) values for all metals except Cd were in low contamination category, whereas Cd values indicated moderate contamination (>1) at different sites. The PLI values obtained for the seventeen stations showed comparatively less status of sediment pollution in the riverine sediments. Although all metal concentrations in the sediment samples were below contamination and pollution levels, the mean EF values for Zn and Cd exhibited minor enrichment (2.08 and 2.77, respectively) suggesting the prevalence of these metals in the study area. Principal component analysis performed using eleven variables revealed both the geogenic and anthropogenic contribution of heavy metals into the riverine system.

The texture of sediments can reveal the source of evolution in river environments. This research was principally conducted to infer the source of the sedimentary process and the effect of the environmental factors on the river sediments in the Arasalar River. To extract the sediment transportation history and distribution of grain size, the research was attempted by analyzing textural properties, heavy mineral, and FT-IR studies of the river debris. The fundamentals of erosion, transportation, and deposition majorly depend on the dynamics of the statistical parameters such as an average or mean (Mz), skewness (Sk_i), standard deviation (σ₁), and kurtosis (K_G). The river's whole basin has extremely coarse to very fine sand that is very poorly sorted to moderately sorted. The sediment exhibited a range of grain sizes, ranging from coarse skewed to extremely fine skewed and had mesokurtic, platykurtic, and leptokurtic characteristics. The analysis of the linear discriminant function indicates that the sediments exhibit dominance in three main processes: fluvial, shallow marine, and turbidity. The beach environment and the presence of shallow, agitated water conditions are observed in the remaining sediment samples. Under CM diagram analysis, the majority of the sediment exhibits the bottom suspension and rolling category. The remaining samples were classified under rolling conditions. The region under consideration exhibits a variety of heavy mineral, including non-opaque and opaque minerals, which can be attributed to their origin in igneous and metamorphic rock formations. The current research focuses on the sediment originating from the Arasalar River, Pondicherry, southern Tamil Nadu, India.

The use of chloroquine (CQ) for the treatment of malaria has gained attention in recent years due to its presence in aquatic environments and the potential environmental threats associated with its persistence. CQ is a commonly prescribed medication during the COVID-19 pandemic, and its presence in river water has been reported. CQ enters into river systems through various pathways such as improper disposal of unused medication, excretion from medically treated individuals, and wastewater discharges from hospitals and pharmaceutical industries. Contamination of river water with CQ raises environmental concerns due to its impact on aquatic ecosystems and its potential threats to human health through drinking water supplies. This chapter provides an outline of the occurrence of CQ in the riverine environment and an in-depth review of all possible transport modelling methods. Transport modelling techniques offer insights into the behaviour and flow of CQ in river systems helping to guide pollution control efforts. Various mathematical models, viz. GREAT-ER, SWAT, WASP Model, and geographical information system (GIS)-based model, have been discussed in the current study. To the best of our knowledge, to date, there are no studies reported on modelling CQ transport in the riverine environment. This review compiles 45 research articles specifically related to models such as fate and transport, hydrodynamic, and GIS-based models used for the modelling of various chemical and emerging contaminants. These models help to identify potential hot spots of contamination and risk assessment to downstream communities. This review provides a new insight into the current knowledge, gaps, and future research needs on possible models which can be used to assess the fate and transport of CQ in the riverine environment.

Temperature can be used as a tracer to characterize vertical recharge rates of fluids through soil. The objective of the present study is to estimate the groundwater recharge from a percolation pond using temperature as a tracer and to assess the temporal and spatial variation on the effect of clogging. Temperature data from different depths at the pond bottom were collected for four different time periods using temperature sensors. These temperature measurements were modelled using the 1DTempPro software. Input parameters required for this model are depth to the temperature sensor from the pond bottom, time series temperature data and sediment properties such as porosity, thermal conductivity, dispersivity and heat capacity. The rate of recharge during the early periods of rainfall is more which gradually decreases afterwards. These results were also compared with the recharge rates calculated by conventional water balance method. The decrease in recharge rate at the pond bottom is attributed to the clogging of suspended particles present in the water. The groundwater temperature data and associated analytical tools are formal solutions for groundwater flow rates and are still underused and not yet utilized to its full potential.