Simulation of Groundwater levels in Malaprabha Command Area using Visual Modflow Flex
Two layered conceptual model covering an area of 705 km2 was prepared using Visual MODFLOW FLEX version 2014.2 to represent the aquifers within Ramdurg, Saundatti (Belgaum district) and Nargund taluks (Gadag district) in the state of Karnataka where the first layer represented the soil layer and second layer was taken as a hard rock layer. Groundwater level data of eight wells available were used for the model simulation. Model domain was split into 120 rows and 120 columns, with each cell having size 472.11 m × 204.03 m. It was simulated for a time period from January 2008 to December 2014 in the transient state with the necessary boundary conditions such as river, reservoir and recharge. After translation and running the model once, it was calibrated by altering the values of sensitive parameters using PEST. Results indicated that the groundwater flow was taking place in two different directions in the study area and was in accordance with the topographical elevation. Dry cells were appearing in the simulated results. which prevented the calibration to be carried out effectively. Hydraulic conductivity, specific storage, specific yield of the first layer and hydraulic conductivity, specific storage of the second layer were sensitive to the model results. Continuous increase in the groundwater head was observed in second layer as the years progressed. Surface water from the Reservoir was contributing to the groundwater in the southern portion of the study area while it remain unaffected to the northern portion of the study area, respectively.
Key Words - Groundwater modeling, Malaprabha Command area, Visual MODFLOW FLEX.