Ground water flow modeling for calibrating steady state using MODFLOW software: a case study of Mahesh River basin, India

Abstract

MODFLOW is a groundwater modelling program. It can be compiled and remedied according to the practical applications. Because structure and fixed data format, MODFLOW can be integrated with geographic information system (GIS) for ground water resource management. Groundwater is a distinguished component of the hydrologic cycle. Groundwater is the water which occupies the voids in the saturated zone of earth’s crust (rocks). It moves and stores in pore space (voids) of sedimentary rocks or in the fractures and joints of hard rocks. The uncertainty about the occurrence, distribution and quality aspect of groundwater and the energy requirement for its withdrawal impose restriction on exploitation of groundwater. In spite of its uncertainty, groundwater is much protected from pollution; it requires little treatment before it use; it is available almost everywhere; it can be developed with little gestation period and can be supplied at a fairly steady rate. A groundwater model is thus a simplified version of the real system that approximately simulates the input–output stresses and response relations of the system. One has to understand here that normally the real system is simplified to model the system as such there is no unique model for a given groundwater system. Groundwater flow models are used to calculate the rate and direction of movement of groundwater through aquifers. The outputs from model simulation are the hydraulic heads and groundwater flow rates which are in equilibrium with the specified hydrogeological conditions (i.e. hydrogeological framework, hydrologic boundaries, initial and transient conditions, hydraulic properties and sources) defined for the modelled area. Groundwater models play an important role in the development and management of groundwater resources, and in predicting effects of management measures. With rapid increases in computation power and the wide availability of computers and model software, groundwater modelling has become a standard tool for professional hydrogeologists to effectively perform most tasks. Then, boundary conditions are adjusted with the aid of a scattergram to reduce bias of the simulated hydraulic head distribution of the equivalent homogeneous aquifer. The differences between the simulated mean hydraulic head and the observed hydraulic head, resulting from small-scale heterogeneities are then reduced by adjustment of local transmissivity values based on the hydrological and geological information. The results of this case study, which produced a number of reasonable as well as some unsatisfying simulations, demonstrate the potential of coupling a surface water model and a groundwater model to obtain more complex and accurate analyses and simulations of hydrologic systems. This paper presents the results of a mathematical groundwater model developed for the Mahesh River basin in the Akola and Buldhana districts, employing conceptual groundwater modelling approach. For this purpose, groundwater modelling software (GMS) was used which supports the Visual Modular three Dimensional Flow-20011 code. For the purpose of modelling the source/sink coverage, recharge coverage, extraction coverage, return flow coverage and soil coverage were considered. The model was calibrated against the historical and observed water level data for the period of 2013 and 2014.