Neyveli basin (Tamil Nadu) is one of the largest sources of Lignite in India. It is present in the 4th layer under ground. After the Lignite is mined, there is a void left by and water gets filled in it during monsoon. My research is to incorporate this void in the existing model (of this area) and see the variation of Ground water level with the variation of Water Level in this void. Is the LAKPackage provided by MOD-FLOW sufficient for this?
Here by, attaching the LAKPackage.
At the end of the day MODFLOW-LAK is just a type 3 BC, so it could probably do the trick, but it's definitely not intended for that kind of void simulation. For that purpose, you could also try to use the GHB condition on the "void" cells, and provide the different water levels as a time series, as this package requires less inputs than the LAK one.
But depending on the size of these voids, you could probably use MODFLOW-CFP. This package is intended for simulation of voids such as fractures, preferential flow layers or submerged mine galleries, which sounds closer than the lake package to what you need to model.
We used very-high-hydraulic conductivity cells (and high storage coefficient) to mimic the dynamics of the mine voids. Also use the STR or SFR (stream flow routing) packages to handle internal mine-to-mine connections across barriers, and discharges via drainage tunnels. A couple of references:
Water budgets and groundwater volumes for abandoned underground mines in the Western Middle Anthracite Coalfield, Schuylkill, Columbia, and Northumberland Counties, Pennsylvania-Preliminary estimates with identification of data needs; 2011; SIR; 2010-5261; Goode, Daniel J.; Cravotta, Charles A. III; Hornberger, Roger J.; Hewitt, Michael A.; Hughes, Robert E.; Koury, Daniel J.; Eicholtz, Lee W.
https://doi.org/10.3133/sir20105261
Surface-water and groundwater interactions in an extensively mined watershed, upper Schuylkill River, Pennsylvania, USA; 2014; Article; Journal; Hydrological Processes; Cravotta, Charles A., III; Goode, Daniel J.; Bartles, Michael D.; Risser, Dennis W.; Galeone, Daniel G. Article Surface water and groundwater interactions in an extensively...
It depends on how long the water stay on the void, the whole year? or just during rainy season only. This will determine which package to use in MODFLOW. As i understand from your question, the water exist only during Monsoon(rainy) season, it means that water has two fate. infiltrate(recharge) or evaporate.If you have a way to determine how much of the water infiltrate, use a positive WELL package, injecting that amount of water toward your aquifer.
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