Groundwater Flow Modeling of a Hard Rock Aquifer: Case Study

Abstract

The present study area is primarily underlain by granites, basalts, and a little bit of laterites. Groundwater occurs under unconfined to semiconfined conditions, in weathered and fractured formations, respectively. A three-dimensional groundwater flow model for the Osmansagar and Himayathsagar catchments-a semiarid hard rock area in India with two conceptual layers-is developed under transient conditions using visual MODFLOW software for the period 2005 to 2009. The 15-20 m top layer is a weathered zone, followed by second 20-25 m-layer fractured zone based on hydrogeophysical studies and borehole lithologs. The groundwater recharge estimation is achieved with the help of geographical information system (GIS) and the water table fluctuation method that is well fitted into the flow model with an average recharge value of 21% of the average annual rainfall. The results derived from modeling indicate that the average input to the aquifer system is 321.96 million cubic meters (mcm), and the output is 322.14 mcm. If the same withdrawal is continued up until the year 2020, the water level is believed to decline more than 45 m over the entire study area. To avoid this critical stage, the present draft should be decreased by nearly 40%.

Integrated hydrogeological modelling of hard-rock semi-arid terrain: supporting sustainable agricultural groundwater use in Hout catchment, Limpopo Province, South Africa

“…This assumption is valid where fractures are prolific, and fracture openings are relatively small compared to the rock volume containing the fractures, and these openings are interconnected (Tiedeman et al 2003). The EPM approach has been successfully applied in fractured rock aquifers (Tiedeman et al 2003;Varalakshmi et al 2012;Hassan et al 2014) and in highly heterogeneous karst aquifers (Larocque et al 1999;Scanlon et al 2003;Ghasemizadeh et al 2015).…”

Application of ERT, Saline Tracer and Numerical Studies to Delineate Preferential Paths in Fractured Granites

“…In this research, the aquifer system was simulated using: (1) EPM and (2) DCM approaches. Most of the fractured aquifer systems in India are being idealized and simulated considering EPM approach (Varalakshmi et al ; Mahadevaswamy et al ; Surinaidu et al ; Ansari et al ). This might be realistic at macroscopic scale, wherein a vague approximation of the complex system with a single continuum may hold good.…”

Current and future groundwater withdrawals: Effects, management and energy policy options for a semi-arid Indian watershed

“…Irrigation withdrawals are a significant water balance component in the semi-arid settings however, because of lack of measured data it is commonly estimated using farmer surveys and sec-ondary data ( Varalakshmi et al, 2012 ). Such estimations can introduce large uncertainty and transfer errors to other components (e.g.…”