Evaluation of water quality of Thuthapuzha Sub-basin of Bharathapuzha, Kerala, India

Abstract Hydrochemical investigation of open well and river water samples of Thuthapuzha Sub-basin of Bharathapuzha, Kerala, was carried out to determine the spatial and temporal variations in the physico-chemical parameters. The suitability of water for drinking and irrigation purposes and the processes controlling the water chemistry were also assessed. The study area experiences a humid tropical climate and heavy rainfall of ~ 3830 mm/year. Thirty-five open well and nine river water samples were collected during the pre-monsoon, monsoon and post-monsoon seasons. The chemical properties of the river water samples were dominated by alkaline earths and weak acids (CaHCO3 type). Even though majority of the open well samples belonged to CaHCO3 type, few samples belonged to NaCl, mixed CaMgCl and mixed CaNaHCO3 water type. The groundwater and river water chemistry of the region was influenced by the chemistry of the host rock rather than precipitation and evaporation. Except pH and the total iron concentration, all other physico-chemical parameters of the open well samples of the study area were within the acceptable limit of drinking purposes. The physico-chemical parameters of the entire river water samples were within the acceptable limit for drinking purpose. The entire open well and river water samples were suitable for irrigation purposes

Isotopic characterization and mass balance reveals groundwater recharge pattern in Chaliyar river basin, Kerala, India

AbstractStudy regionThe Chaliyar river basin, Kerala State, India.Study focusDetailed understanding about spatio-temporal variation in the interaction and exchange of water between surface and sub-surface reservoirs is important for effective watershed management. Spatio-temporal variations in the oxygen isotopic composition (δ18O) were used to understand the interaction between groundwater and river water, and to estimate the groundwater recharge from river water in the Chaliyar river basin.New hydrological insights for the regionBased on the spatio-temporal variation in δ18O values of river and groundwater and fluctuation in ground water levels, following important inferences are made: (1) estimated river water contribution to post-monsoon groundwater recharge is ∼16% in the lowland coastal area of the Chaliyar river basin and 29% in midland region; (2) northeast winter monsoon rains contribute to the groundwater of Chaliyar river basin only in an insignificant manner, and with a delayed response; (3) unlike river water samples which exhibit both seasonal and spatial variation of more than 3‰, the groundwater samples vary only marginally (∼1‰) between the seasons and across the physiographic zones; (4) groundwater samples exhibit inverse altitude gradient in δ18O values in the highland zone, in all the three seasons. This may be due to flow of the isotopically depleted groundwater down the gradient and evaporation of residual water in the upper reaches of the basin

Studies on stable isotopic composition of daily rainfall from Kozhikode, Kerala, India

<p>The stable isotopic compositions of all major daily rain fall samples (<i>n</i> = 113) collected from Kozhikode station in Kerala, India, for the year 2010 representing the pre-monsoon, southwest and northeast monsoon seasons are examined. The isotopic variations δ¹⁸O, δ²H and <i>d</i>-excess in daily rainfall ranged from δ¹⁸O: −4.4 to 2 ‰, δ²H: −25.3 to 13.8 ‰, and <i>d</i>-excess: −2.4 to 15.3 ‰; δ¹⁸O: −9.7 to −0.6 ‰, δ²H: −61.7 to 5.3 ‰, and <i>d</i>-excess 5.8 to 17.4 ‰; δ¹⁸O −11.3 to −1.4 ‰, δ²H: −75.3 to 0.9 ‰, and <i>d</i>-excess: 8.8 to 21.3 ‰ during the pre-, southwest and northeast monsoon periods, respectively. Thus, daily rainfall events during two monsoon periods had a distinct range of isotopic variations. The daily rain events within the two monsoon seasons also exhibited periodic variations. The isotopic composition of rain events during pre-monsoon and a few low-intensity events during the southwest monsoon period had imprints of secondary evaporation. This study analysing the stable isotopic characteristics of individual rain events in southern India, which is influenced by dual monsoon rainfall, will aid in a better understanding of its mechanism.</p

A study on landslides and subsurface piping, facilitated by dykes, using vertical electrical sounding and δO \u3c sup\u3e 18 \u3c/sup\u3e and δH \u3c sup\u3e 2 \u3c/sup\u3e stable isotopes

© 2017, Springer-Verlag Berlin Heidelberg. A combination of vertical electrical sounding (VES) and δO18 and δH2 stable isotope geochemistry is used in this study to trace out the extension of a dyke and for deciphering the subsurface piping phenomena in a landslide-affected hamlet, Pasukadavu, in the Western Ghats of Kerala, India. VES was successful in extracting three to four different subsurface layers characterized by differing resistivity. Two VES sections were prepared from 24 different VES locations, each one for understanding the dyke extension and for delineating subsurface conduits. The dyke was characterized by high resistivity of 800–5000 Ω.m and shows varying thickness. In the second profile, the void zone, which is characteristic of piping, is delineated through a low resistivity zone (75 to 350 Ω.m). δO18 and δH2 stable isotopes collected along the second VES profile show the same chemistry, indicating that it is the same water which flows all along the VES profile 2. A four-stage conceptual model was developed to illustrate and narrate the sequence of development of the piping phenomena and landslide activity