EGU21-14145, updated on 04 Mar 2021
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Spatial distribution of groundwater-surface water connectivity in the Kosimegafan, north India

Zafar Beg1, Suneel Kumar Joshi2, Kumar Gaurav1, and Sudhir Kumar2
Zafar Beg et al.
  • 1Department of Earth and Environmental Sciences, Indian Institute of Science Education and Research, Bhopal, India (zafar17, kgaurav)
  • 2Hydrological Investigations Division, National Institute of Hydrology Roorkee, Uttarakhand, India (joshisuneelkumar, sudhir.nih)

We conducted a systematically integrated surface water and groundwater interaction study in the Kosimegafan in north India using the stable isotopes (δ18O and δ2H) of water and depth to water level data. In a field campaign in December 2019, we have collected a water sample from 65 different locations for isotopic analysis. This includes 21 samples from the groundwater and 44 from different surface water bodies (Kosi River-02, streams-09, waterlogged patches-29, and canal-04).

The δ18O and D-excess values of groundwater and waterlogged samples show marked spatial variation across the study area. Using a two-component mixing model, we estimate the fraction contribution of streams and rainwater in the groundwater and waterlogged patches. This shows a marked spatial and depth-related variability in stream water contribution to the groundwater recharge and varies from about 83% (maximum) at 6 m below ground level (bgl) to 45% (minimum) at 9 m bgl. We also analysed the spatial and temporal variation in groundwater levels from 1996 to 2017. During this period, the water level shows a significant variation from 1.1 to 7.8 m bgl. Further, using the water table fluctuation approach, we estimate the recharge rate. We found a higher recharge rate (22 mm/year) in the central part of the western lobe and northern part of the central lobe, and minimum (1 mm/year)in both the northern part of the western and southern part of the central lobe of the Kosi fan. This study provides new insight into the recharge processes in the study area.

How to cite: Beg, Z., Joshi, S. K., Gaurav, K., and Kumar, S.: Spatial distribution of groundwater-surface water connectivity in the Kosimegafan, north India, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-14145,, 2021.