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Über dieses Buch

This book contains selected peer-reviewed papers presented in the International Conference Down To Earth 2019, and is focused on Water Security and Sustainability. The topics covered in this book include sustainability of water resources, geospatial modelling and hydro-informatics, extreme hydrology (drought and flood), adaptation to climate-change impacts, vulnerability-risk-reliability-resilience, and hydrological risks in north-east India. The book also discusses innovative techniques and technologies for water resources assessment and management. Enriched with numerous case studies covering diverse topics, the book can be valuable for students, researchers, as well as industry professionals interested in water resources assessment, management and sustainable development.

Inhaltsverzeichnis

Frontmatter

Water Resources Assessment

Frontmatter

Numerical Analysis of Water Movement in Agricultural Fields with Heterogeneous Unsaturated Soils

Abstract
The natural variability exhibited by soil hydraulic properties poses severe challenges to model water movement through porous formations in agricultural fields. In this study, a 3D numerical approach coupled with the turning bands method to generate realizations of soil formation properties with different heterogeneity levels to solve the governing partial differential equation in variably saturated soils was used to simulate field scale water flow to investigate the impact of soil heterogeneity and root water uptake on subsurface flow dynamics in cropped fields. Soil moisture, suction head and hydraulic conductivity were observed to be significantly affected by heterogeneity of the media and root water uptake. Soil heterogeneity was found to increase soil water content while root water uptake was decreasing it. The effect of root water uptake on soil moisture distribution was more pronounced under homogenous soils than in heterogeneous soils. Soil suction head decreases with increasing soil heterogeneity whether root water uptake was considered or not. Hydraulic conductivity increases with increasing soil heterogeneity when root water uptake was ignored, and it depends on the heterogeneity level when root water uptake was accounted.
Ephrem Yetbarek, Richa Ojha

Three-Dimensional Numerical Simulation of Pressure-Flow Scour

Abstract
An estimate of scour depth is required in the design of bridges. Much of the research on scour estimation has focussed on the local scouring, i.e. scouring near abutments or around piers. In comparison, contraction scouring has received less attention. Contraction scouring occurs when the waterway is contracted either laterally or vertically. During extreme flood events, the water level may rise above the bottom chord of the bridge, creating a pressure-flow situation in the passage below the bridge. The pressure scour thus induced is not clearly understood in terms of its location, geometry and time evolution. Some recent experimental studies have tried to establish empirical relations between scour parameters and various properties of flow, fluid and bed material. However, numerical approach has not been employed to study the pressure scour. The present study is an attempt to numerically simulate the pressure scour caused due to vertical contraction. International River Interface Cooperative (iRIC) solver NAYSCube is used to simulate the flow over mobile bed. NAYSCube, an open source 3D flow solver, employs finite volume method to solve Navier–Stokes equations and couples turbulence and bed-load models. Due to the limitations of the computational capacity, the simulations are performed to generate the flow and bed data for a period of one hour. The approaching flow velocity, channel slope and the sediment size of the bed are kept constant. The results show that bed shear has the maximum value inside the contraction section. The scour hole is observed to develop within the contraction towards the upstream face of the contraction. The magnitude of maximum scour is found to increase with increase in degree of contraction or length of contraction or both. The study establishes the need to conduct more numerical simulations to investigate pressure-flow scouring.
Sofi Aamir Majid, Shivam Tripathi

Contamination of Arsenic in Groundwater of Bara District, Nepal

Abstract
Groundwater is the major source of water for drinking and household purposes in Nepal’s Tarai districts. This study was conducted to evaluate the concentration of arsenic (As) in deep and shallow groundwater and its association with iron, manganese, depth and age of the tube wells/dug wells in Bara District. Groundwater samples (36) were collected from randomly chosen wells (dug wells and tube wells) of Bara District, in 2017. As concentrations of water were measured by hydride generation atomic absorption spectrometry (AAS). About 50% of tube wells/dug wells exceeded permissible value 10 ppb of WHO drinking water guideline, but 16% tube wells/dug wells exceeded permissible values of Nepal Interim Standard of arsenic (50 ppb). As concentrations were highly correlated with iron and manganese. The higher concentrations of As in some of the sites of the study area were attributed to the groundwater geochemistry in the study area. As contamination was found high at the depth range of tube wells <20 m, which was constructed in last 10–15 years. The risk of As contamination to the people living in and around study area is high because the contaminated water has been used daily for household purposes such as cooking, drinking and other purposes.
Sadhana Pradhanang Kayastha, Kailash Pradhanang

Runoff Prediction Using Artificial Neural Network and SCS-CN Method: A Case Study of Mayurakshi River Catchment, India

Abstract
Runoff estimation, as well as forecasting, is a challenging hydro-climatological topic since governing physical processes is complex, and in reality, it is hardly represented by a system of the equations. Due to the complex nature and extreme spatial-temporal variability of the processes which control runoff, it is difficult to set up a reliable framework for runoff prediction and forecasting based on available observations only. In this research, two kinds of methods have been approached. The first one is a conceptual method, Soil Conservation Service Curve Number (SCS-CN) method, which combines the climatic factors and watershed parameters in one unit called the  Curve Number (CN). The other method is the Artificial Neural Network (ANN) modeling, where two different kinds of models, Feed Forward Back Propagation (FFBP) and Cascade Forward Back Propagation (CFBP) model have been applied. The runoff-rainfall coefficient has been chosen as the standard parameter of the study result. Among 16 years, the year 2000 has the highest annual, seasonal monthly total runoff (monsoon season, July to Sept.). In artificial neural network models, generated coefficient correlation (R) values varied from 0.96 to 0.99 range, which indicated a good correlation between the rainfall-runoff data set. The models developed for the present study can be utilized for further basin hydrologic analysis.
Subhadeep Mandal, Sujata Biswas

Water Quality and Designated Best Use (DBU) Determination of Bhim Taal Lake of Panchkula, Haryana

Abstract
There are large number of water sources available on earth such as oceans, springs, lakes, and ponds but not all the water sources can be considered as usable. Only 2.5% out of the available sources of water are freshwater and only 1% out of them can be considered as an accessible source; considering this fact lakes can be considered as a reliable source of water comprising of about 0.3% of freshwater resources available to humans for use, they have been used for years as a source of water for drinking, bathing, washing, swimming, and other recreational activities. Since there is an availability of limited amount of freshwater resources, the optimum utilization of the available resources should be the major area to focus upon. The sustainability concept needs to be implemented for the water resources because discovering the new water sources for fulfilling the ever-increasing demands of humans is not possible. The anthropogenic activities around the lakes have deteriorated the quality of lakes; therefore, there is a need for maintenance of these water resources based on the determination of degraded water quality characteristics and utilizing the water according to the designated best use based on the measured values of the parameters. In this study, we focus on the utilization of a lake as a source for drinking, bathing, propagation of wildlife and fisheries and industrial and irrigational use based on the parameters measured and in comparison with the guidelines issued by Central Pollution Control Board (CPCB). The site has been utilized for years by local communities for their personal use but no study has been made for the determination of the parameters and putting the water body to use according to the DBU neither the developmental activities has been seen and reported for the site to be used as a source of water for human and animal consumption. The samples were collected for the site and tested in the laboratory for determination of values of various parameters. The values were then compared with the values of DBU table issued by Central Pollution Control Board (CPCB) for various parameters to determine the designated uses of the water body. The project is at an initial stage and a single sampling program has been carried till now as a first step toward optimum utilization of the water source.
Prachi Vasistha, Rajiv Ganguly

Hydrochemical Analysis of Six Sacred Lakes of Sikkim

Abstract
Sikkim, the north-eastern state of India has more than 200 lakes, whose serene beauty attracts tourists from all over the world. Some of the lakes act as the sources for drinking water while some are considered sacred and are used for religious purpose. Chemical analysis of lake water may provide vital information about the possible reasons of anomaly, level of pollution, if any as well as effect of anthropogenic activities. In the present study, water chemistry of six important and sacred lakes of Sikkim, namely Gurudongmar, Lamapokhari, Kheheopalri, Karthok, Menmecho and Kupup, has been analysed and critically examined. Water samples were collected from these lakes and their chemical analysis has been carried out. General water quality parameters of these water samples were tested and compared with the standards laid by the Bureau of Indian Standards (BIS) and the World Health Organization (WHO) to find whether the lakes are suitable for domestic and agricultural uses. Results have revealed difference in the lake water quality of these lakes with respect to different chemical parameters. Anomalous concentrations of dissolved oxygen (DO), calcium (Ca) and total dissolved solids (TDS) obtained in water samples of certain lakes have been examined and correlated with natural and anthropogenic factors. This paper has discussed the possible reasons of anomalous chemistry of these sacred lakes and has advocated for their environmental protection.
Roshni Chettri, Dipankar Tuladhar, Chandrashekhar Bhuiyan

Determination of Best-Fit Probability Distribution of Rainfall Data in Sikkim, India

Abstract
Rainfall is an essential input in design of various hydraulic structures, urban planning, disaster management, and agriculture. In this study, an attempt is made to identify the probability distributions that best fits the rainfall data of Sikkim, India. Monthly rainfall data is collected in four rain gauge stations in Sikkim and the best-fit probability distributions of the rainfall data in each station in annual, dry, and wet seasons are identified. Goodness-of-fit tests such as χ2, log-likelihood, Akaike information criterion (AIC), and Bayesian information criterion (BIC) are used to test the fit of probability distributions on the empirical data.
S. Kiran, David Raj Micheal

Hydro-informatics and Geospatial Modelling

Frontmatter

Suitable Locations of Ocean Renewable Energy in Coastal Indian State—Kerala

Abstract
India, a diverse nation, is filled with variegate natural resources, most of which can be utilized for the production of energy, and in many cases, acting as an appropriate substitute to the pollution causing conventional power sources. Being largely a peninsula, India has a huge coastline facing the open ocean, representing a vast renewable energy source in the form of ocean currents, tidal energy, ocean winds, and wave energy, which can be utilized to account for an additional economical and eco-friendly energy reserve for the nation. This paper spatially explores Kerala, a state in India, having nearly 580 km of coastline in the Arabian Sea, using a Quantum Geographic Information System (Q-GIS)-based analysis, to gist out the areas available for generation of various forms of ocean renewable energy. Among the considered beaches, three beaches: Bekal, Kozhikode, and Cherai is found to be suitable for both wind and wave energy, while the other beaches adhere to either wind or wave energy. It is also concluded that ocean currents can be used as an energy source throughout the coastline of Kerala. Such an approach can also be applied to researches of similar nature, benefitting industries who are dealing with the same genre of development.
D. Ghose, S. Naskar, Shabbiruddin

Study of Temporal Behaviour of Homogeneity Maps for Estimating Representative Area of a Ground Sample Using Remote Sensing

Abstract
Modelling and prediction of hydro-meteorological variables over land and atmosphere involve ground sampling at selected locations over the study area. Optimally selecting the number and location of sampling points is important for making reliable predictions without escalating project costs. This study proposes an approach for selecting sampling locations by considering inter-dependency of predictor variables and the prediction variable using remote sensing data. A homogeneity map, i.e., a thematic map representing areas with the same expected value of the prediction variable, with a given level of uncertainty and spatial resolution, is generated. The homogeneity maps can be different at different times for the same location. Thus, along with the spatial variability of the prediction variable, its temporal variability is also obtained. Depending on the obtained variability, a decision on the number and location of sampling points can be taken prudently. In this paper, the proposed methodology is demonstrated by considering soil moisture over an experimental watershed as the prediction variable.
Prasad J. Deshpande, Anudeep Sure, Onkar Dikshit, Shivam Tripathi

Water Pipeline Routing Using GIS

Abstract
Pipeline route selection problem through an area is one of the oldest spatial challenges because of various influencing factors such as topography, geographic, geophysical, earth’s surrounding and anthropological. It is a demanding issue which requires advanced scientific approaches to determine the shortest, most direct and cost-efficient route. This study identifies and evaluate various factors (elevation, slope, land use, rail and road network, water areas, etc.) influencing the pipeline route selection and develop a Geographical Information System (GIS)-based model to find the optimal pipeline route from Hanumangarh District to Jhunjhunu District using least cost approach. The proposed methodology involves calculation and unsupervised classification of the Euclidian distance for all factors. Classified rasters are then further reclassified and weights for different factors are provided using weighted overlay method to combine all the raster into a single raster image. Finally, the least cost path of the pipeline is determined using least cost tool of ArcGIS software. This research results provide a time-saving and efficient least cost path and proves the suitability of using ArcGIS in planning an optimal pipeline route.
Varun Jain, Ramneek Singh Bhamra, Maitreya Mishra, Rajiv Gupta

Predicting Meander Migration of the Barak River by Empirical and Time Sequence Methods

Abstract
Common phenomena associated with the alluvial river is its ‘meandering’. Lateral migration of the Barak River creates geomorphic hazards in Assam, India. Predicting and preventing this migration are both difficult and necessary. In this article, we have tried to describe and evaluate the empirical approach and time sequence maps to predict meander migration. An empirical approach is based on correlations, while as, for a given meander, earlier observed movement is used in case of sequence method to predict the future migration. In this study, 12 meandering reaches of the Barak River are considered using multiperiod Landsat remote sensing images. In order to evaluate the accuracy of these methods, both predicted migrations, as well as measured migration, are compared. Results show that empirical methods are not precise and accurate, though some of the empirical methods are conservative, and some are unconservative. More accurate, precise information on the meandering movement is given by time sequence method to predict the radius of the best-fit circle of the future meander location.
Wajahat Annayat, Briti Sundar Sil

Identification of groundwater recharge potential zones using AHP and Fuzzy Logic: A blockwise study of western Purulia district, India

Abstract
Managing groundwater resources, particularly under data-scarce and dry regions, involves a lot of difficulties and problems which have driven the planners to apply remote sensing (RS) and geographic information system (GIS) based procedures. In the present study, groundwater recharge potential zones are delineated by integrating the Analytic Hierarchy Process (AHP), GIS, and RS methods in five blocks of Purulia district, India. At first, the adequate thematic layers of factors impacting the groundwater recharge potential, such as drainage density, geomorphology, soil types, land use, geology, rainfall, slope, and lineament density, are extracted from sources like satellite imagery and collateral data. The AHP method is utilized to estimate the weights of different layers for applying the hierarchical fuzzy logic to identify potential zones for groundwater recharge. It is found that about 186.35 km2 area has very good groundwater recharge potential (GRP), which is only 12.13% of the total study area. The area with good, average, and low GRP are about 359.08, 455.29, and 415.44 km2 respectively. Analyzing the blockwise distribution of potential zones, it is found that Baghmundi block having 21.9% and 27.76% of its area under very good and good GRP zones respectively, is most suitable for blockwise implementation of groundwater recharge sites.
Sauvik Santra, Sujata Biswas

Simulation of Runoff for Subarnarekha Catchment Using SWAT Model

Abstract
This paper is based on Soil and Water Assessment Tool (SWAT) which is a hydrological model that integrates the Geographic Information System (GIS) with the attribute database to simulate runoff. SWAT Model is basically executed in association with ArcGIS as ArcSWAT. The study area taken is Subarnarekha River which flows through the eastern part of India over the states of Jharkhand, West Bengal, and Odisha. In this paper, Digital Elevation Model (DEM) has been used for delineating the catchment area. Remote sensing data has been used as input in ArcSWAT for delineation of catchment area determination of drainage pattern, land use/land cover, slope, etc. To develop landuse/landcover map the satellite imagery from Landsat 8 was acquired and the soil map for the study area was obtained from Harmonized World Soil Database (HWSD) Raster world soil map. Hydrological Response Unit (HRU) analysis was performed which resulted in 25 subbasins and 194 HRUs. Then by using 11 years of daily rainfall data, SWAT simulation has been performed to estimate the monthly and yearly runoff for their respective rainfall. The annual rainfall-runoff of the Subarnarekha River from 2005 to 2015 has been plotted and found the maximum rainfall of 1811.62 mm and runoff of 595.65 mm is in the year 2007. The reliable accuracy of the model has been checked with the assessment of the model performance as with the rainfall-runoff correlation coefficient which was found to be 0.971.
R. Murmu, S. Murmu

Spatial Disparity in Access to Improved Source of Drinking Water and Sanitation Facility: A District-Level Assessment in India

Abstract
More than one billion people worldwide are deprived of basic facilities including clean water sources and sanitation. Although many countries achieved progress through the millennium development goal, countries in South Asia like India still face the problem. More than 163 million people in India do not have access to clean water. Out of the 60% of the world population without access to drinking water, India tops the list by contributing 19.33%. Poor sanitation not only has a direct influence on well-being but also has an indirect impact on the living conditions, reduced education outcomes, and poverty. As of 2018, about 8% of the population in India still do not have access to an improved sanitation facility. The present study aims to assess the presence of spatial clustering in the proportion of households with access to an improved source of drinking water and sanitation facility at the district-level in India, using the data from national surveys. The study also aims at the temporal assessment of the clustering pattern during the period of 2007–2008 and 2015–2016. Spatial analytical techniques such as exploratory mapping and spatial cluster analysis are performed. The findings of this study are useful in locating the districts that lack access to an improved source of drinking water and sanitation facility. This information can further help in implementing targeted intervention programs to achieve the sustainable development goal of clean water and sanitation by 2030.
Amitha Puranik, Nilima, Sushmitha Prabhu

Extreme Hydrology

Frontmatter

Flood Hazard Mapping and Vulnerability Analysis Along Seti River in Pokhara Metropolitan City

Abstract
Flood is frequent during every monsoon in Nepal which poses threat to life and property in lowland areas. Among 6000 rivers and rivulets, most are prone to floods in Nepal. Seti River flows from Machhapuchhre Rural Municipality in the north, along the center of Pokhara Metropolitan City, and toward Tanahu which meets with Madi River there. Seti flood of 2012 was one of the devastating floods which took the life of many people and destroyed infrastructures along its way. So, Pokhara Metropolitan City lies at a high risk of flood impacts. Hydrodynamic simulation using HEC-RAS and GIS is one of the important methods of estimating the probable loss due to flood of various scenarios quantitatively. In this study, flood hazard maps of Seti River across Pokhara Metropolitan City has been prepared for different flood scenarios. The flood frequency analysis was performed using Gumbel, Log-Pearson, Log Normal, and Fullers Method. The goodness of fit was performed using chi square test, and results of Gumbel method was used as it was found more appropriate than other methods for this basin. One-dimensional steady hydrodynamic modeling was done to create water surface profile which was used to prepare hazard maps and vulnerability maps for various return periods. The model was evaluated using statistical parameters, coefficient of determination R2), and Nash–Sutcliffe efficiency (NSE) whose values were found to be 0.951 and 0.819, respectively. The maps prepared can be used for planning the built-up areas along the river sides and may help in decision making for flood mitigation measures.
Anup Shrestha, Saraswati Thapa, Bhola Nath Sharma Ghimire

Bed-Bank Relationship and Flood Characterisation in the Upper Reach of the Brahmaputra Valley, Assam

Abstract
Brahmaputra valley relief of upper Assam in India bears plenty of evidences to suggest active structural control as well as remarkable unevenness in sediment budgeting. These two major forcings cause highly variable bed-bank relationships along different reaches of the Brahmaputra’s channel belt. Under steady average annual precipitation in decadal scale, flood vulnerability can be taken as directly proportional to the decreasing rate of bed-bank elevation difference. Normally, average bed elevation of the highest order river of a given valley reach is the base level of the reach. Bed-bank architecture over the years shows different reach scale possibilities. A big braided river like the Brahmaputra shows alternating narrower ‘nodes’ and wider ‘internodes’. Usually, nodes are deeper and anti-nodes are shallower. Reach scale widening of rivers over time on many occasions is accompanied by shallowing tendency as well. For the upper reach of the Brahmaputra River and the valley, reach scale plano-temporal variability for the period 1915–2015 was monitored. From the confluence of three major rivers, the Siang, the Dibang and the Lohit, up to 230 km downstream, 23 reaches each of 10 km width were chosen. Essentially we have four findings. First, by measuring plano-temporal variability of sandbar/channel areas we could locate reaches having steady rate of aggradation; secondly, two indices for depths and widths were developed which help to identify normalised deeper zones and zones showing normalised widening tendency over three different average widths (1915, 1975 and 2015). This also helps to test the validity of the general assumption whether shallower reaches show a general trend of widening or not for the upper reach of the Brahmaputra valley. Thirdly, by assuming discretisation of the flow into equal width reaches, probable flood inundation areas were identified for incremental jumps of water levels over the average bank elevations by 0.5, 1.0, 1.5, 2.0 and 2.5 m assuming absence of embankments. Lastly, assuming complete embankments for both the banks exclude the possibility of immediate flooding but accelerate thereby the river bed construction and practically zero bank construction which can be interpreted in terms of disaster incubation. For uniform aggradation all along the river bed of the study area, reaches having river bed elevation equal or higher than the bank elevation will be more prone towards embankment breaches. Accordingly, for different aggradation thickness values of 0.5, 1.0, 1.5, 2.0 and 2.5 m within the channel belt, the incubation of vulnerability for different reaches of both the banks was identified.
Siddhartha Kumar Lahiri, Angkuran Sarma, Robert James Wasson

Innovative Techniques and Technologies

Frontmatter

Control of Sediment Entry into Intake Canals Using Submerged Vanes with Collar

Abstract
Intake canals transport water and sediments from main rivers to power plants, irrigation fields, and for various other purposes. Increased sediment load in the intake canal leads to reduction in the quality and quantity of water. Submerged vanes are installed at the entrance of intake canals to counteract the secondary circulation and reduce the sediment entry into the intake canals. In the present study, collars have been introduced to submerged vanes to test its performance in the reduction of both sediment entry and local scour around vanes. The vane angles tested are 15°, 35°, 40° and 45°. The ratio of vane spacing to vane height is 5 and the two collar diameters considered are three and four times the vane height, respectively. It is found that 40° is the optimum vane angle for maximum reduction in sediment entry into the intake canal of 85.36%. Collars reduced the local scour and sediment entry (%) by a maximum of 69.08% and 24.84%, respectively, for a 15° vane angle. However, introduction of collar reduced the performance for vane angles 35°, 40°, and 45° in controlling sediment entry into the intake canal.
Sruthi Thazhathe Kalathil, Muralidharan Rethinam Murugesan, Venu Chandra

Effectiveness of River Bed Filtration in Pollutant Removal Along the River Tel, India

Abstract
Riverbank filtration (RBF) is a cost-effective water treatment technology. In this method, infiltrated surface water is extracted through a pumping well which is located nearby alluvial aquifer. In the process of infiltration surface water is treated by various mechanisms like biological, chemical, and physical processes; hence, water extracted from pumping well is free from pollutants. Although riverbank filtration (RBF) was used extensively in United States and Europe, but there are no proven scientific researches done related to RBF use in Odisha. This paper is aimed to present a concise summary of the theoretical foundations of the RBF technique and its benefits. The paper also reports the effectiveness of bed filtration in reducing turbidity, phosphates, coliform, and nitrates from water of River Tel at Belagaon, Balangir District, in Odisha.
Rajiv Lochan Sahu, Rakesh Roshan Dash, Pradip Kumar Pradhan, Sourava Sahu

Removal of Organic Matters and Nutrients by Using Bio-balls and Corn Cobs as Bio-film Carrier in MBBR Technology

Abstract
Water is our life’s most significant component. It is used to cook, bathe, drink, wash, and for various industrial purposes. Due to urbanization, over exploitation and industrialization of water bodies throughout the world lead to degradation of water quality. Therefore, high water quality is needed, resulting in the need to develop modern and cost-effective techniques to remove organic matter and nutrients from wastewater. Moving-bed bio-film reactor (MBBR) method is one of those methods that are used effectively in this situation. The purpose of this research was to explore the effectiveness of the MBBR method in removing chemical oxygen demand (COD), nitrate, phosphate from wastewater using bio-balls and corn cobs as bio-film media. Synthetic wastewater was prepared in laboratory by taking different concentration of COD, nitrate, and phosphate. By using bio-balls as a bio-film carrier, the maximum removal efficiency of COD, nitrate, and phosphate was obtained to be 84%, 95.48%, and 96.93%, respectively, whereas for corn cobs, the maximum removal efficiency of COD, nitrate, and phosphate was found to be 72.39%, 94.63%, and 93.7%, respectively. The result obtained from the experiment confirmed that this process can be effectively used to treat domestic and industrial wastewater containing different pollutants.
Akankshya, Rakesh Roshan Dash, Siprasthiti Mohanty

An Overview on the Photocatalytic Application of Transition Metal–ZnO Nano-Photocomposites for Degradation of Textile Effluents in Water

Abstract
Water remediation has become an urgent requirement to meet the growing need of water scarcity. Organic dyes emanating from the textile industries without proper treatment are a major source of water pollution and, therefore require urgent treatment. This overview is based on one such strategy of converting organic dyes present in aqueous medium into inorganic components by the process of photocatalysis. Photocatalytic dye degradation has been considered with transition metal–zinc oxide (ZnO) nano-photocomposites (NPC) owing to their excellent photo-physical properties. This overview covers three important aspects of photocatalysis using transition metal–ZnO NPC: (i) requirement of photocatalytic dye degradation and photocatalysis, (ii) need for an optimum transition metal dopant/deposit percentage and (iii) the underlying mechanism occurring during photocatalysis upon UV, visible and UV–Visible light irradiations.
Parita Basnet, Somenath Chatterjee

An IoT-Based Water Management System for Smart Cities

Abstract
Water conservation is one of the prime concerns in the current scenario where environmental conditions are deteriorating at an alarming rate. Smart cities, unlike the conventional system of living, are in the frontline of innovation in terms of both connectivity and technological advancement. The main idea is to use the available technology to make life easy with lesser harm to the environment. An Internet of Things (IoT) and data analytics (DA) based water management system will be a basic ground for implementation and future research on how data and IoT can be used to make this happen. This paper proposes an Internet of Things (IoT) and data analytics (DA) based water distribution cum management system that would help in optimal distribution of water based on user consumption at the plot holding level. The proposed system would not only save water misuse but also help in storing usage data for analysis and town planning at a macro-level.
Immanuel Savio Donbosco, Udit Kr. Chakraborty

Comparative Study of Scouring Around Bridge Piers

Abstract
Excessive scouring around bridge piers is one of the main causes for bridge failures. Scour is not easily noticeable because it is hidden under the channel flow. Scour around a bridge pier is a challenging problem to planners and hydraulics researchers because of the adaptation of some empirical formulas. The basic reason of such adaptation of empirical formulas is due to lack of monitoring of such complex problem, and hence, the mechanism of scouring is not fully understood. Most of these scour prediction empirical formulas was based primarily on flume experiments. Thus, the knowledge of precise maximum scour depth for a given hydraulic and geotechnical condition is essential for proper design of foundation of the bridge piers as under predicted scour depth will lead to bridge failures, and over prediction of scour depth will lead to unnecessary construction costs. Since most of the scour prediction equations are based on laboratory experiments, it is important to analyse the hydraulic characteristics of the river before and after the construction of the bridge. In this study, analysis has been carried out to understand the influence of different parameters such as sediment size and the shape of the pier using different empirical equations. In India, Indian codes for scour estimation uses Lacey’s regime equation for scour depth estimation for the hydraulic design of bridges, which are having certain limitations. Thus, the objective of this study is to obtain a better understanding of the mechanism which causes scouring by considering hydraulic and geotechnical characteristics. Therefore, in the present study, an attempt has been made to investigate the effect of different parameters on scour around bridge piers. The results obtained were compared with equations and models used by other researchers and found that Lacey’s equation is giving over predicted values than other empirical equations.
P. Sreeja, Supradeep Singh

Quantification and Characterization of Microplastics in Kanke Lake, a Freshwater System of Ranchi, Jharkhand, India

Abstract
Plastics of particle size less than 5 mm are termed as microplastics. These are one of the most influential emerging contaminants, in terms of sustainable water resource. The present study shows the degradation of quality of freshwater systems in terms of occurrence and abundance of microplastics in surface water and sediments of freshwater systems, which leads to degradation of drinking water quality. This study was executed on Kanke dam (a lake), located in Ranchi district, which is the prime source of drinking water for the population of urban settlements. The sampling was carried out in three stretches, i.e., pisciculture area, water supply area and Ranchi municipal park area. The sampling of surface water is done with the help of Manta net, fabricated using mesh size of 125 µm, and sediments were collected with the help of trawl in aluminum foil. The trapped particles in Manta net were collected and sieved through 63 µm sieve. The raw sample was purified using H2O2 in presence of Fenton’s reagent which acts as catalyst, followed by density separation using NaCl. The supernatant was collected on filter paper and quantified using stereomicroscope (fluorescence microscopy). The concentration of microplastic particles was maximum in pisciculture area followed by park area and water supply area. The count of microplastics particles quantified was 300 particles in 100 m3 of water. The chemical nature of the collected microplastics was identified using FTIR technique. Polystyrene, polypropylene, polyethylene (low-density and high-density) and polyurethane were common polymers observed in the samples. Identification of the chemical nature of the microplastics indicates their probable sources and thus can be a useful tool to minimize the abundance by source correction.
Vicky Singh, Sukalyan Chakraborty

Numerical Simulation of Positive Surge Moving Upstream

Abstract
The study is focused on numerical simulation of one-dimensional unsteady flow in open channels using MacCormack Scheme. This scheme is an explicit numerical method for simulating one-dimensional and two-dimensional unsteady flow. This study is focused on depth and velocity variation in different sections of a rectangular flume at different time intervals. A series of experiments were performed on a multipurpose tilting flume on two different slopes viz., (a) nearly horizontal (zero slope) and (b) 3% slope. Experimental results are compared with the results of a computer program developed on the FORTRAN 90–95 programming language for simulating the MacCormack scheme. Results obtained from the developed code show comparable trends with the experimental result.
Yatindra Kumar, Dhrubajyoti Sen, V. R. Desai, Abhranil Adak

Error Estimation for Forecasting of Orographic Rainfall Using Regression Method

Abstract
Forecasting model of monthly orographic rainfall, which is fundamentally characterized by a long occurrence period within a year not having much of maximum rain rate values, has been developed using regression approach. The analysis has been done on the basis of historical data of rainfall of two hill stations of different altitude, Majitar and Ghum. Performance of the developed model is evaluated through exhaustive error calculation. Goodness of fit value shows that the performance of the developed model is acceptable for the two stations having different altitude. F-test shows the statistical reliability of the prediction of rainfall. Lower root mean square error (RMSE) value indicates good prediction of stochastic-deterministic events like orographic rainfall.
Pooja Verma, Swastika Chakraborty, Pragya Jaiswal
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