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DRASTIC method's vulnerability assessment for estimating the potential risk of contamination in shallow groundwater aquifers is the most acceptable technique. The method uses seven parameters, namely, depth to groundwater table, net recharge, aquifer media, soil media, topography, land use and land cover, and hydraulic conductivity to obtain vulnerability index values. These index values are validated with one or a few elements of water characteristics as pollution indicators. In most of the reported studies, the correlation coefficient between the DRASTIC index and the concentration of individual element(s) was low. The present study uses the water quality index (WQI) to correlate with the DRASTIC index value. In this paper, 11 physical and chemical water characteristics data of 31 well locations within the Faridabad District of Haryana, India are utilized to estimate the WQI. The correlation coefficients for single element concentration with DRASTIC index vary between the range of 0.104 to 0.304. The correlation coefficients for the concentration of NO3 - and WQI are found to be 0.104 and 0.533, respectively. Thus, the DRASTIC index demonstrates a stronger correlation with the WQI when compared to single element concentration. [ABSTRACT FROM AUTHOR]

With the increasing population and per capita demand for freshwater, the burden of natural resources has increased many folds. Indian agriculture is still largely dependent on conventional methods of crop production that are mainly inefficient. Water security is essential for social and economic development, having an indispensable role in enhancing health, well-being, and economic progress, particularly in a developing country like India. Water footprint (WF) is an important indicator that helps ascertain the direct and indirect use of water in any process. WF modeling in agriculture enables us to pinpoint the impacts and limitations of the current crop production system. Assessing vulnerabilities across various regions and time helps us prepare actions to improve water productivity and promote sustainable water use. There is considerable spatial variability in blue, green, and gray WF among the different states of India due to their varied climate, soil, and topographic characteristics. WF assessment is critical for developing water allocation strategies, planning water trade, making policies, and implementing remedial measures. This paper describes the significance of WF and its proper management for sustainable crop production in India. [ABSTRACT FROM AUTHOR]

The groundwater recharge area is one of the crucial components in regional development. Many studies in determining groundwater recharge areas with a combination of Geographic Information System and Multi-criteria Decision Analysis have been carried out. The development of studies over the last ten years is reviewed in this paper using the PRISMA systematic review method to find out the study’s progress. A total of 31 studies were found in the previous ten years based on the review results. Information about the country of origin of the study, dominant geology, climatic conditions, criteria used, decision-making and weighting methods, and the validation process for each study were extracted. The results show 12 countries researching this topic, with five dominant geological classes and nine classes of climatic conditions, and 33 criteria are used in the 2011–2021 range with eight dominant criteria used. Four decision rules and the weighted method are used, and a validation process is commonly used with well data. From systematic review and meta-analysis, we conclude: India has become the country that has most researched this topic. Hard-rock-class geology is dominant and arid and semi-arid climate conditions have become the main focus of studies. The variability of criteria is up to 33 with 18 criteria still used only once in each study, and eight dominant criteria have been used. Analytical Hierarchy Process (AHP) and Multiple Influence Factor (MIF) have become the most-used methods for assigned weight, and Frequency Ratio (FR) is the newest method for assigned weight. Lithology has the highest weight compared with the other seven dominant criteria, and well data has become the most common data for verification of groundwater recharge. [ABSTRACT FROM AUTHOR]

Munroe Island in Kollam District of Kerala is a typical backwater village situated at the confluence of the Ashtamudi backwater and the Kallada River system. It is an amalgamation of eight small islands with a total area of 13.4 km². Salinity intrusion has been a serious threat in the downstream areas of Kallada River for more than one and half decades, affecting the groundwater quality of Munroe Island. The present study focuses on the seasonal variation in physico-chemical characteristics of the underground water system of Munroe Island and Kallada River with special reference to saline water intrusion. Physico-chemical analysis of ground water revealed that samples were unsuitable for drinking due to higher content of Na, Ca, and K. Microbiological analysis of island groundwater showed the presence of coliform and E. coli bacteria above the permissible limit. Results indicated a significant correlation between salinity and major anions viz., Cl- and SO4² and cations viz., Mg, Na, Ca, and K of both river surface and island groundwater. In the present study it is clearly evident the occurrence of saltwater intrusion in Kallada River from Ashtamudy Lake and the its severity become higher during premonsoon season. The results also indicated that the salinity increase in Kallada River has a negative impact on island groundwater quality. The paper also suggests suitable management strategies for overcoming the saltwater intrusion thereby upgrading island sustainability. [ABSTRACT FROM AUTHOR]

About 3,500 small community based reverse osmosis (RO) plants have been installed in Rajasthan, India to comply with the recent Government of India guidelines for drinking water quality in rural areas. This paper presents the performance of four RO plants of Bharatpur, which face frequent replacement of membrane modules primarily due to accelerated scaling of carbonates and sulphates of calcium. A detailed chemical analysis of different streams from these plants was carried out to assess the reasons of scaling through a mass balance approach. The chemical analysis was substantiated through ion balance and the scaling potentials were analysed through different saturation indices. Efficacy of antiscalant usage plants was further assessed through mass balance approach followed by detailed characterization of the RO membrane to understand the complete fouling process, which brought out subtle differences in brackish and seawater desalination. The membranes adopting commonly used antiscalant showed an enhanced life span of 2-2.5 year by reducing calcium carbonate scaling but not calcium sulphate scaling. This study highlights the requirement of customized antiscalant application according to the feed characteristics. With a better understanding of the fouling phenomenon, this study would help enhance the life of membrane in RO plants treating brackish water. [ABSTRACT FROM AUTHOR]

Water supply services in India are currently not regulated and remain essential monopolies under the strict control of government. These services are mostly perceived as inefficient, reflecting insufficient municipal revenue generations which result in loss-making municipalities that need to be subsidized by the government. The efficiencies and productivities remain largely unmeasured and undetermined, and therefore the perception of inefficient services is not backed by scientific studies. This paper therefore sets up a framework for measuring the performance and productivity of Indian water supply operations. The study utilizes panel data on 21 municipalities observed over the financial years 2005 and 2010, to analyze the relative efficiencies and productivity growths of utilities. Data envelopment analysis is used to obtain efficiency scores and productivity measures such as the Malmquist index. The results indicate the presence of large relative inefficiencies and decreasing productivity of water supply services over time, alluding to a failure to revise tariffs upwards despite increasing input costs over time, thereby driving the need for sector regulation and tariff revision in accordance with X-factors, which was found to have a mean value of 2.4% for possible price cap regulation in the sector. The paper highlights related policy implications. [ABSTRACT FROM AUTHOR]

Security concerns about water distribution networks (WDNs) have led to increased interest in optimizing sensor locations in WDNs achieved through a calibrated hydraulic model. This paper presents a methodology, which consists of two stages. The first stage consists of calibration of a hydraulic model using a genetic algorithm (GA). A real-life network of one of the hydraulic zones of Nagpur city, India, is considered, which optimizes the settings of a throttled controlled valve at different timings for calibration. In this stage, a detailed case study, GA calibration model, methodology and results of calibrated models are discussed. The second stage consists of identifying optimal sensor locations using a newly developed software tool named 'S-PLACE GA' and its efficiency and effectiveness are discussed. It can be used for the dual purpose of routine monitoring of water quality and for early detection of contamination. The optimal locations are obtained considering two objective metrics, 'Demand Coverage' and 'Time-Constrained Detection Likelihood'. These two objectives are combined into a single objective by using weights. Key features, input data required for the software and their applications on (1) BWSN network 1 and result comparison with others and (2) calibrated model of the first stage are discussed. Results showed the effectiveness of S-PLACE GA for practical applications. [ABSTRACT FROM AUTHOR]

Calibration of a hydraulic model is a challenging task as it considers the involvement of a large number of uncertain parameters. There are some parameters like length and diameter of pipes, for which fairly accurate values can be obtained. As with all hydraulic models, water demands are one of the main parameters that cause the most uncertainty in the model outputs. The calibration of the water demands is usually not feasible, which is attributable to the limited quantity of available measurements in most real water networks. However, some parameters like nodal demands and pipe roughness coefficients are estimated close to the actual values. Various types of valves are used for flow control by throttling. Hence, their setting in the field is also an important input to the model. Having more precise data helps in reducing time and results in better calibration as presented in the case study of one hydraulic zone served from Ramnagar Elevated Service Reservoir (ESR) (Zone II) in Nagpur City, Maharashtra State, India. This paper aims at presenting the complexities and challenges involved in calibration of the study area. It further describes the entire process from collection of the required data to the calibration of the network. [ABSTRACT FROM AUTHOR]

The past decade has witnessed discussions on various options to overcome groundwater depletion, such as rainwater harvesting (RWH) and 'artificial recharge' methods. This paper addresses law and policy issues relating to managed aquifer recharge (MAR). Based on an analysis of the National Water Policy of India and water polices and laws of the Indian states, a concrete case study, namely Chennai metropolitan area, has been studied in detail. The city of Chennai and the State of Tamil Nadu provide a favorable atmosphere for groundwater recharge, making, e.g. RWH mandatory. However, the legal framework does not support more systematic approaches towards MAR and the administrative praxis does not ensure that groundwater recharge is offset by an increase of illegal groundwater extraction. [ABSTRACT FROM AUTHOR]