International audienceThe major part of groundwater in India is found in granitic aquifers. Fluoride in groundwater from a crystalline aquifer in a semi-arid region of granitic rocks in India, known as Maheshwaram watershed, was analyzed for spatial and temporal variability during 1999-2002 to assess the effect of hydrogeological factors on fluoride concentration. Samples were collected from 32 representative wells in the area for the pre- and post-monsoon seasons and analyzed for F content. The CHESS computer program was used to calculate ionic activities of aqueous species and the mineral saturation index (SI) for calcite and fluorite. The GARDENIA computer program was used to calculate the recharge values in the study area. The influences of dissolution kinetics of fluoride minerals and recharge from rainfall on fluoride concentration were of interest and results clearly indicate that fluoride content in groundwater depends on the interaction period of groundwater with host rock. Results could also be utilized for designing remedial measures particularly with dilution method in an optimal way
International audienceIrrigation return flow coefficients, i.e. the ratio between the quantity of water returned from the cultivated area to the groundwater system and the amount of abstraction, vary by more than 50% for rice cultivation using standing water irrigation to 0% in the case of drip irrigation technique. This component of the groundwater budget plays an important role, particularly in intensively irrigated areas. Thus, to avoid any inaccurate aquifer budgeting, modelling and consequently any erroneous watershed management, this component needs to be accurately assessed for a particular time-step (e.g. weekly, seasonally) onto the studied area. The present paper proposes a cost-effective and useful methodology for assessing irrigation return flow coefficients (Cf D irrigation return flow/pumping flow) based on (i) basic crops field survey and meteorological data and (ii) the use of a simple hydraulic model that combines both water balance technique and unsaturated/saturated flow theory. An attempt to estimate the uncertainty of irrigation return flow coefficient estimates based on the uncertainty introduced by the pumping and the natural spatial variability of the soil characteristics is also proposed. Results have been compared to real field conditions and allow us to (i) estimate the uncertainty and (ii) validate and demonstrate the robustness of the applied methodology. The proposed methodology allows relatively good estimates of the irrigation return flow coefficients at watershed and seasonal scale. The irrigation return flow coefficients are calculated as: 51 š 8% in rainy season (Kharif) and 48 š 4% in summer (Rabi) for rice; 26 š 11% in rainy season and 24 š 4% in summer for vegetables; 13 š 8% in rainy season and 11 š 3% in summer for flowers. These results were found to be consistent with the existing literature
derstanding groundwater systems and their functioning through the study of stable water isotopes in a hard-rock aquifer (Maheshwaram watershed, India). Journal of Hydrology, Elsevier, 2011, 397 (1-2), pp. 55-70. 10.1016/j.jhydrol.2010.11.033 . hal Groundwater degradation through abstraction, contamination, etc., shows a world-wide 15 increase and has been of growing concern for the past decades. In this light, the stable
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.