Suchergebnisse

To minimize and counter decline of groundwater levels and improve the availability of water for cropproduction, Managed Aquifer Recharge (MAR) interventions are widely adopted across India, often ini-tiated or supported by, local communities, state and central governments to improve the availability ofwater for irrigation. While the literature on MAR in India is vast, the science of their construction is lack-ing. Furthermore, there is an absence of a structured approach to evaluate the performance and impactof MAR interventions. Often, performance and impacts of MAR have been commented upon together,without distinguishing the two.In this article, we aim to propose that performance and impact are different from each other, andthat the evaluation of MAR interventions should take into account such differences between them. Aframework for performance and impact analysis, based on three levels, viz. primary, secondary and ter-tiary, is outlined. It is then applied to seven selected MAR interventions in India, Adarsha watershed –Andhra Pradesh, Gokulpura-Goverdhanpura watershed – Rajasthan, Kodangipalayam watershed – TamilNadu, Chikalgaon watershed – Maharashtra, Rajasamadhiyala watershed – Gujarat, Satlasana watershed– Gujarat and Sujalam Sufalam Yojana – Gujarat. Although, the evaluations of these case studies reportedwere not categorized into performance and impact, most of them have addressed both. However, noneof them could explicitly demonstrate that reported impacts were uniquely related to MAR interventions.If impacts are used as a surrogate for performance, it must be shown that impacts are uniquely linked toMAR interventions.

Abstract. The present research is aimed at accessing the relationship between variation in the soil gases radon (222Rn) and helium (4He) and recently developed fissures and other neotectonic features in Nurpur and Nadha areas of the NW Himalayas, India. Two soil-gas surveys were conducted on/near known faults to reconfirm their position using soil gas technique and to check their present activity. During these surveys, soil-gas samples were collected along traverses crossing the observed structures. The data analysis reveals that the concentrations of radon and helium along the Dehar lineament and the longitudinal profile (Profile D) are very high compared to any other thrust/lineament of the Nurpur area. The Nadha area shows high values of radon and helium concentrations along/near the Himalayan Frontal Fault (HFF) as compared to the adjoining areas. This indicates the presence of some buried fault/fault zone running parallel to the HFF, not exposed to the surface and not delineated by satellite data but is geochemically active and might be tectonically active too. Hence, soil helium and radon gas patterns have been combined with morphological and geological observations to supply useful constraints for deformation of tectonic environments.