Browsing by Author "Sharma, Rakesh K."
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Item Open Access Assessment of traditional rainwater harvesting system in barren lands of a semi-arid region: a case study of Rajasthan (India)(Elsevier, 2022-06-25) Yadav, Basant; Patidar, Nitesh; Sharma, Anupma; Panigrahi, Niranjan; Sharma, Rakesh K.; Loganathan, V.; Krishan, Gopal; Singh, Jaswant; Kumar, Suraj; Parker, AlisonStudy region Dudu station, Rajasthan, India Study focus Rainwater harvesting can be used as a method to recharge aquifers. This can happen with a variety of scales and technologies. One such example is shallow infiltration ponds (Chaukas) which recharge groundwater and increase soil moisture facilitating pastureland development. A HYDRUS-1D model was used to estimate potential groundwater recharge. The model was calibrated using field data from 2019 and validated using data from 2020. The time series of Normalized Difference Vegetation Index (NDVI) was derived at annual scale to assess changes in the vegetation cover. New hydrological insights for the region The modeling revealed that an additional 5% of the rainfall depth was being recharged into the groundwater. In addition, the additional soil moisture was allowing natural grass cover to develop, which could be used by the local community as pastureland. These twin benefits that the local communities are realizing could be scaled up beyond Dudu, to India, and worldwide, as many regions have barren land that is slightly sloping, together with permeable soils, which are the only conditions for the construction of Chaukas. These Chauka systems have helped in sustainable water resources management in these water-stressed regions and the additional livelihood support through developed pastures for animal husbandry.Item Embargo Release of geogenic fluoride from contaminated soils of Rajasthan, India: experiments and geochemical modeling(Elsevier, 2023-07-12) Thakur, Bhawna; Loganathan, Vijay A.; Sharma, Anupma; Sharma, Rakesh K.; Parker, AlisonManagement of groundwater contaminants, that are primarily of geogenic origin, such as fluoride, is a major public health concern. Worldwide, around 200 million people are dependent on drinking water resources that contain elevated levels of fluoride that exceeds WHO’s drinking water threshold limit of 1.5 mg/L. According to the Ministry of Drinking Water and Sanitation of India, about 11.7 million people, mostly in the Rajasthan state, are exposed to high fluoride risk. It is important to understand the soil–water interaction mechanisms to properly assess the fluoride contamination that are primrily due to geogenic origins prevalent in the region. In this study, batch desorption experiments were performed with soils obtained from varied depths at two sites in Rajasthan that has high fluoride levels in groundwater. The fluoride release kinetics followed a pseudo first-order kinetic model. The results of the batch experiments indicate higher release of fluoride from lower soil layers when compared to the upper layers. Further, the release of fluoride was dependent on pH wherein higher release was noticed under basic pH. Since the natural pH of the soils from this region is ca. pH 8 it is expected to play a vital role in the continued release of fluoride to the groundwater system. Furthermore, a simplified geochemical model, incorporating a general composite approach, has been used to simulate the experimental results that include dissolved Al and Al-F surface complexes. The model was able to capture the observed experimental results for various soils within a reasonable RMSE of 11.74%. The results of this study not only further the current understanding of the fate and transport mechanisms of fluoride in the contaminated subsurface but also would aid in designing remedial strategies to ensure future water security in this region.