609 research outputs found
Institutional Vacuum in Sardar-Sarovar Project: Framing ‘Rules-of-the-Game’
No full textFew large irrigation projects in India have been as elaborately planned as the Sardar- Sarovar Project (SSP), incorporating as it did the lessons of decades of irrigation project design and management. The project was to blaze a new trail in farmer-participatory irrigation project design and management with water user associations (WUAs) building their own distribution systems. However, as it unfolds, the institutional reality of the project is seen to be vastly different from its plans. If SSP is to chart a different course from scores of earlier large irrigationprojects, it must invent and put into place new rules of the irrigation management game.Length: pp.95-106Irrigation programsRiver basinsGroundwater irrigationSurface irrigationWater users associationsWater allocation
Investigation of groundwater consumption to cope with the inadequate piped water supply in continuous and intermittent supply systems: A case study in Bangalore, India
No full text[EN] Although the supply of piped water to the Indian cities is increasing, the demand is not always fulfilled. This gap in water demand and supply is usually bridged by using alternate sources of water, mostly groundwater. Bangalore, the capital city of Karnataka, is one of the fastest developing metropolitan cities in India is also facing piped water supply issues. The groundwater is the main source of alternate water supply in the city. In the present study, a District Metered Area (DMA) is selected in the Bangalore South-West division; this DMA has both intermittent and continuous water supply systems. The water distribution network (WDN) of study DMA contains four inlets and three supply zones. The first is a continuous water supply system whereas the second and third are the intermittent systems. The impact of inequitable supply in the study DMA is evaluated and the consumption of groundwater to cope with insufficient water supply is analyzed. The Lorenz Curve and Gini Coefficient are used to assess the inequity in groundwater extraction under intermittent and continuous supply zones. The data from the field flowmeters, consumer meter reading, and door-to-door questionnaire survey are used for the analysis. The questionnaire survey includes RR number, presence of wells/borewells, horsepower (HP) of the pumps used, building type, the number of inhabitants, and the floors in each building. In the continuous supply system, a questionnaire survey was untaken for 80% of the connections, whereas in the intermittent supply system random sampling was used. The questionnaire survey analysis showed that 53% of the consumers in the continuous supply system rely on piped water supply, whereas others used groundwater as well as piped water supply. The study illustrated the gap in groundwater consumption between supply zones within intermittent water supply systems as well as between intermittent and continuous water supply zones. Reliability on groundwater was high even in continuous supply systems indicating insufficient pressures resulting in unsatisfied demands. The study indicated that just increasing the access to the piped water supply to the consumers is not sufficient, the acceptable quality with adequate pressure of water should be delivered to reduce the use of groundwater. The inferences from the study can be used to regulate groundwater extraction.Priyanka, B.; Bharanidharan, B.; Sheetal Kumar, K.; Mohan Kumar, M.; Srinivas, V.; Nibgoor, SR.; Kishore, Y. (2024). Investigation of groundwater consumption to cope with the inadequate piped water supply in continuous and intermittent supply systems: A case study in Bangalore, India. Editorial Universitat Politècnica de València. https://doi.org/10.4995/WDSA-CCWI2022.2022.14821OC
Three-Dimensional Modelling of Heterogeneous Coastal Aquifer: Upscaling from Local Scale
No full textThe aquifer heterogeneity is often simplified while conceptualizing numerical model due to lack of field data. Conducting field measurements to estimate all the parameters at the aquifer scale may not be feasible. Therefore, it is essential to determine the most significant parameters which require field characterization. For this purpose, the sensitivity analysis is performed on aquifer parameters, viz., anisotropic hydraulic conductivity, effective porosity and longitudinal dispersivity. The results of the sensitivity index and root mean square deviation indicated, that the longitudinal dispersivity and anisotropic hydraulic conductivity are the sensitive aquifer parameters to evaluate seawater intrusion in the study area. The sensitive parameters are further characterized at discrete points or at local scale by using regression analysis. The longitudinal dispersivity is estimated at discrete well points based on Xu and Eckstein regression formula. The anisotropic hydraulic conductivity is estimated based on established regression relationship between hydraulic conductivity and electrical resistivity with R2 of 0.924. The estimated hydraulic conductivity in x and y-direction are upscaled by considering the heterogeneous medium as statistically homogeneous at each layer. The upscaled model output is compared with the transversely isotropic model output. The bias error and root mean square error indicated that the upscaled model performed better than the transversely isotropic model. Thus, this investigation demonstrates the necessity of considering spatial heterogeneous parameters for effective modelling of the seawater intrusion in a layered coastal aquifer
Direct and Inverse Modeling of Seawater Intrusion: A Perspective
No full textSea Water Intrusion (SWI) is one of the major hydrological problem in coastal aquifers. This global issue is aggravated by increasing demands for freshwater in coastal regions. In this paper, different approaches of modeling SWI and the parameters affecting the process of SWI are introduced. This is followed by the discussion on the numerical models to solve the complex, three dimensional (3D) groundwater and solute transport problems in coastal aquifer. The importance of considering aquifer characteristics while modeling the groundwater system for flow and solute transport is emphasized. A brief discussion on previous methodology, novelty and limitations on direct simulation of SWI are tabulated. The significant aspects to be considered while direct modeling of coastal aquifers are discussed and the recent focus of research in this area of interest are stated. In direct modeling, information on aquifer parameters are often unknown, therefore, an inverse approach is explained briefly. The previous studies relating to determistic inverse modeling for coupled groundwater flow and solute transport problems reported in literature are summarized. The insights about prior information, estimated parameter sensitivities, variances and correlations are reported. The paper identifies some of the existing gaps in the modeling of SWI based on the previous work and provides comprehensive understanding on direct and deterministic inverse SWI modeling
Comparison of ANN models for predicting water quality in distribution systems
No full textDeterministic models have been widely used to predict water quality in distribution systems, but their calibration requires extensive and accurate data sets for numerous parameters. In this study, alternative data-driven modeling approaches based on artificial neural networks (ANNs) were used to predict temporal variations of two important characteristics of water quality chlorine residual and biomass concentrations. The authors considered three types of ANN algorithms. Of these, the Levenberg-Marquardt algorithm provided the best results in predicting residual chlorine and biomass with error-free and ``noisy'' data. The
ANN models developed here can generate water quality scenarios of piped systems in real time to help utilities determine weak points of low chlorine residual and high biomass concentration and select optimum remedial strategies
Numerical modelling of oxygen mass transfer in diffused aeration systems: A CFD-PBM approach
No full text•Multiphase CFD model coupled with discrete PBM equation.•Effective air bubble size reduces with height of water column.•Bubbles have a wide distribution, with larger diameter near bottom.•Bubbles have a narrow distribution with small bubble size at the top.•Higher H/B ratio result in increased rate of DO saturation at fixed airflow rate.
The diffused aeration process is the most energy-intensive operation of bioreactor treatment, amounting to 45–75 % of the plant energy costs. To improve its efficiency, it is essential to measure the oxygen transfer rate from the aerators to wastewater. In this study, a multiphase mixture computational fluid dynamics (CFD) model is developed using k-ε turbulence closure equations along with a discrete population balance model (PBM) add-on with specific bubble classes, to predict the oxygen mass transfer. The transfer of oxygen species from air to water is modeled using the species transport model. The PBM is used to analyze the formation, growth, breakage, and coalescence of air bubbles. The validated model is then extended for sensitivity analysis for a diffused aeration system in a bench-scale aeration tank. Results show that, the volumetric oxygen mass transfer coefficient increases by 15 %, with a decrease of air bubble size by 10 %. The air bubbles have a wider distribution, with a larger diameter near the bottom of the bioreactor and a narrow distribution with a smaller bubble size at the top. Results show that, in the bioreactor, the dissolved oxygen concentration reaches the equilibrium or saturation value when the height by breadth ratio is 2.5 and does not increase further with increase in height of the water column. Also, the air bubble size of 6 mm was the efficient bubble size for a fixed airflow rate of 1.45 m3 h−1
Tuning of PID controllers for water networks—different approaches
No full textBetter operational control of water networks can help reduce leakage, maintain pressure, and control flow. Proportional integral derivative (PID) controllers, with proper fine-tuning, can help water utility operators achieve targets faster without creating undue transients. The authors compared three tuning methods, in different test situations, involving flow and level control to different reservoirs. Although target values were reached with all three tuning methods, the methods’ performances varied significantly. The lowest performer among the three was the method most widely used in the industry—standard tuning by the Ziegler-Nichols method. Achieving better results was offline tuning by genetic algorithms. Achieving the best control, though, was a fuzzy logic–based online tuning approach—the FZPID controller. The FZPID controller had fewer overshoots and took significantly less time to tune the gains for each problem. This new tuning approach for PID controllers can be applied to a variety of problems and can increase the performance of water networks of any size and structur
H. J. Bhabha : a case study of synchronous references
No full textQuantitative analysis of the events of synchronous references in the research papers followed throughout the publishing career of an individual scientist revealed interesting highlights on the knowledge-generating-system. In the case study of Homi Jehangir Bhabha first quinquennium and fifth quinquennium of his research career had low Self-references; third quinquennium and fourth quinquennium had moderate Self-references; whereas second quinquennium had highest Self-references. The two major clusters of Self-references occurring during the second and third quinquennium were indicators of active periods of knowledgegenerating and faster communications.(Revised version published in 2006 in International Journal of Nuclear Knowledge Management,Vol.2. No.1. pp.14-30. see PDF2
Comparative study of three types of controllers for water distribution networks
No full textA water distribution system consists of numerous appurtenances that are interconnected, creating a network comprising nodes and branches. Basic process variables are used to describe the behavior of these elements and nodes, and control of these process variables is important for proper operation of a distribution system. The authors describe an alternative controller that combines the nonlinear control technique known as dynamic inversion (DI) with proportional integral derivative (PID) features to cope with existing control problems. Proportional derivative (PD) and PID controllers are presented and compared with DI-based robust nonlinear controllers. In this study, emphasis is given to determining how quickly a water distribution system can be controlled in order. to reach different targets within a short time and without creating undue transients. In this regard control algorithms play an important role in real-time control of a water distribution system. Thus, development of controllers for pumping and valve operations can significantly improve any water distribution system with respect to reducing leakage, maintaining pressure, and controlling flow in the entire network
Effect of capillarity and heterogeneity in the numerical modelling of multiphase flow of fluids in unsaturated porous medium
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