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Publications:
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Abstract
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In the last decade, researchers have underscored the need for carrying out climate change analysis at regional and sub-regional levels. Against this backdrop, we analyzed the climatic variability and environmental changes that occurred during the last seven decades (1958 -2019) and their impact on groundwater variability in South Bihar, India. We employed a mixed-method approach and analyzed both the quantitative scientific data and qualitative ethnographic data collected from the local farmers. The scientific data was compiled for the climatic parameters (rainfall and temperature), hydrological parameters (runoff, actual evapotranspiration, potential evapotranspiration, and climate water deficit), terrestrial water storage, and groundwater storage capacity using TerraClimate model and Global Land Data Assimilation System. The public perception of climatic variability and environmental change was analyzed using farmers' understanding of environmental variability in selected villages of South Bihar. In terms of climatic variations, the historical climatic data showed rainfall variability over the last seven decades. Higher unpredictability in monsoon rainfall is evident from the 1990s onwards. The average temperature had gone up by 0.5 oC over the study period. The surface and groundwater deficit across South Bihar was relatively high (above 600 mm) with a significant sub-regional variation. From the public understanding perspective, the climatic variations were mostly narrated in terms of deficit and erratic rainfall, which increased in recent decades. Farmers explained the groundwater scarcity and associated environmental changes based on their lived experience. Both scientific and farmers' understanding of environmental variability explains the high climatic variability during the last three decades.
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Abstract
In India in recent decades, groundwater has emerged as a principal source for meeting drinking and irrigation needs. As a result, groundwater depletion and overextraction are acknowledged as a major concern. Different policy interventions are being explored to augment the management of aquifers. Aquifer storage and recovery (ASR) is one such intervention that is becoming popular among government agencies, developmental actors, and even farmers for recharging and recovering water from aquifers. However, the selection of a suitable location and appropriate aquifer for recharge is challenging. The main objective of this study was to classify site selection criteria for ASR installations in different types of aquifers in North India. In this study, both scientific indicators (i.e., rainfall, elevation, soil and aquifer characteristics, surface and groundwater quality) and social characteristics (tacit knowledge, land ownership, willingness to participate) were evaluated to create an integrated ASR site selection criterion. The results indicated that ASR sites could not be appropriately identified solely based on available metrological, geospatial, and geohydrological data. Socioeconomic parameters should be an integral part of the decision-making process for the site selection for ASR. Based on these scientific indicators and social characteristics, a total of seven potential ASR sites (three in the village of Nekpur and four in the village of Meyar) were selected at Rajgir, Nalanda, Bihar, India. Although this integrated site-assessment framework was designed based on 12 indicators in the context of the marginal alluvial plains for the mid-Ganga regions in this study, the general principles adopted in this study can be applicable to other regions.
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Abstract
Growing dependence on groundwater to fulfill the water demands has led to continuous depletion of groundwater levels and, consequently, poses the maintenance of optimum groundwater and management challenge. The region of South Bihar faces regular drought and flood situations, and due to the excessive pumping, the groundwater resources are declining. Rainwater harvesting has been recommended for the region; however, there are no hydrogeological studies concerning groundwater recharge. Aquifer storage and recovery (ASR) is a managed aquifer recharge technique to store excess water in the aquifer through borewells to meet the high-water demand in the dry season. Therefore, this paper presents the hydrogeological feasibility for possible ASR installations in shallow aquifers of South Bihar with the help of flowing fluid electrical conductivity (FFEC) logging. For modeling, the well logging data of two shallow borewells (16- and 47-m depth) at Rajgir, Nalanda, were used to obtain the transmissivity and thickness of the aquifers. The estimated transmissivities were 804 m2 /day with an aquifer thickness of 5 m (in between 11 and 16 m) at Ajatshatru Residential Hall (ARH) well. They were 353 and 1,154 m2 /day with the aquifer thicknesses of 6 m (in between 16 and 22 m) and 2 m (in between 45 and 47 m), respectively, at Nalanda University Campus (NUC) well. Despite the acceptable transmissivities at these sites, those aquifers may not be fruitful for the medium- to large-scale (more than 100-m3 /day injection rate) ASR as the thickness of the aquifers is relatively small and may not efficiently store and withdraw a large amount of water. However, these aquifers can be adequate for small (up to 20- m3 /day injection rate) ASR, for example, groundwater recharge using rooftop water. For medium- to large-scale ASR, deeper aquifers need to be further explored on these sites or aquifers with similar characteristics.
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4. Sharma, A. & Sharma, P. (2022) How climate vulnerability in South Bihar takes a toll on its groundwater. Down To Earth, Center for Science and Environment, New Delhi.
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5. Sharma, P. (2022). Role of aquifer storage & recovery on water resources management, international webinar on geospatial technology & water resources management, International Institute of Geospatial Science & Technology, Kolkata, India.
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Abstract
Among the several options of managed aquifer recharge (MAR) techniques, the aquifer storage and recovery (ASR) is a well-known sub-surface technique to replenish depleted aquifers, which is contingent upon the selection of appropriate sites. This paper explores the potential of ASR for groundwater recharge in the hydrological, hydrogeological, social, and economic context of South Bihar in India. Based on the water samples from more than 137 wells and socio-economic surveys, ASR installations were piloted through seven selected entrepreneurial farmers in two villages of South Bihar. The feasibility of ASR in both hard rock and deep alluvial aquifers was demonstrated for the prominent aquifer types in the marginal alluvial plains of South Bihar and elsewhere. It was postulated through this pilot study that a successful spread of ASR in South Bihar can augment usable water resources for agriculture during the winter cropping season. More importantly, ASR can adapt to local circumstances and challenges under changing climatic conditions. The flexible and participatory approach in this pilot study also allowed the farmers to creatively engage with the design and governance aspects of the recharge pit. The entrepreneurial farmers-led model builds local accountability, creates avenues for private investments, and opens up the space for continued innovation in technology and management, while also committing to resource distributive justice and environmental sustainability.
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7. Sharma, P. (2021). An integrated site selection model for aquifer storage and recovery, Indian National Chapter of International Association of Hydrogeologists.
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9. Verma, P. et. al. (2020). Integrating top-down and bottom-up perspectives for site selection for aquifer storage and recharge. Fall Meeting, AGU Fall Meeting, San Francisco, CA, H163-0013.
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11. Sharma, P. et. al. (2019). Artificial recharge and reuse of suddenly available water in South Bihar, India. Fall Meeting, AGU Fall Meeting, San Francisco, CA, H11L-1659.
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