Details

Autor(en) / Beteiligte

• Das, Prerona
• Mukherjee, Abhijit
• Hussain, Syed Aaquib
• Jamal, Md. Shahid
• Das, Kousik
• Shaw, Ashok
• Layek, Mrinal K.
• Sengupta, Probal

Titel

Stable isotope dynamics of groundwater interactions with Ganges river

Ist Teil von

• Hydrological processes, 2021-01, Vol.35 (1), p.n/a

Ort / Verlag

Hoboken, USA: John Wiley & Sons, Inc

Erscheinungsjahr

2021

Quelle

Wiley Online Library

Beschreibungen/Notizen

• Groundwater depletion has been an emerging crisis in recent years, especially in highly urbanized areas as a result of unregulated exploitation, thus leaving behind an insufficient volume of usable freshwater. Presently Ganges river basin, the sixth largest prolific fluvial system and sustaining a huge population in South Asia, is witnessed to face (i) aquifer vulnerability through surface waterborne pollutant and (ii) groundwater stress due to summer drying of river as a result of indiscriminate groundwater ion. The present study focuses on a detailed sub‐hourly to seasonally varying interaction study and flux quantification between river Ganges and groundwater in the Indian subcontinent which is one of the first documentations done on a drying perennial river system that feeds an enormous population. Contributing parameters to the total discharge of a river at its middle course on both temporal and spatial scale is estimated through three‐component hydrograph separation and end‐member mixing analysis using high‐resolution water isotope (δ18O and δ2H) and electrical conductivity data. Results from this model report groundwater discharge in river to be the highest in pre‐monsoon, that is, 30%, whereas, during post‐monsoon the contribution lowers to 25%; on the contrary, during peak monsoon, the flow direction reverses thus recharging the groundwater which is also justified using annual piezometric hydrographs of both river water and groundwater. River water‐groundwater interaction also shows quantitative variability depending on river morphometry. The current study also provides insight on aquifer vulnerability as a result of pollutant mixing through interaction and plausible attempts towards groundwater management. The present study is one of the first in South Asian countries that provides temporally and spatially variable detailed quantification of baseflow and estimates contributing parameters to the river for a drying mega fluvial system. Temporally and spatially variable river baseflow quantification and differential interaction of river water and groundwater is evaluated through mixing model using high‐resolution stable isotope signatures of water. This hydrological exchange pattern varies depending on river morphometry. The results from this model helped in understanding multi‐scale hydrodynamics, hydro‐chemical response and aquifer vulnerability for a growing population on a prolific fluvial aquifer system.