Critical Assessment of Groundwater Overflow Zone for Sustainable Management in North East India

Groundwater level depletion has now become a crisis that requires global concern. Most of the rivers of Tripura, India are perennial in nature but in recent days they became dry due to siltation in the upper and lower sections of the streams hampering the conjunctive interaction between riverine and groundwater systems. Groundwater overflow zone acts like an artesian well where it perceives a pressure by the overlying hard rock terrain within the aquifer resulting in the rise of groundwater above the ground level without using a pump. The objective of the present study is to identify the aquiferic overflow zones over the plain land and hilly areas and to assess the impact of hydrological parameters over the aquifer discharge for sustainable conservation. The required hydro-meteorological, hydrogeological, and morphological datasets of the study have been collected from different primary and secondary sources of government and non-government organizations. Geophysical and geoelectrical surveys are carried out at different points and which validated accordingly with the help of lithological strata as obtained from bore log data. The discharge rate of the aquifers is obtained through 48 h continuous pumping test conducted under the study. Overflow zones are delineated in the map using AutoCAD. Valley-wise discharge rate varied between 29.5 m3/h and 136.3 m3/h having an aquifer thickness of 28.5 m and 36.4 m respectively embedded with different types of sandstone within the overflow zone. The results show a quantitative aquifer discharge from the flat areas compared with the hilly regions. The study concludes that the uncontrolled discharge from the groundwater potential zones may cause the deterioration of water quality and flooding problem may occur in the areas as well. Water retaining structures at suitable location could be an alternative measure for long-term sustainable solution.