I agree with Kevin M Befus

2D method if properly interpreted can give the distribution of subsurface hydraulic/geologic/electrical properties. MUDFLOW/MODPATH uses locally refined grids to simulate groundwater flow within the subsurface or on surface. The interpretation of the MUDFLOW/MODPATH can give information about the hydraulic and hydrogeologic units. With the 2D data interpretation, salinity concentration can be determined with fidelity if the analysis/interpretation is constrained by nearby lithologic logs and the water levels can be determined using MUDFLOW/MODPATH.

I agree with Kevin M Befus and Nyakno jimmy George .

I would add that if your only concerns are groundwater levels and concentrations, it's probably more effective to drill a few boreholes to take direct measurements because they do not tend to vary abruptly in space (of course you can always do a surface ERT survey before your drill). Logging the boreholes will also help you come up with K values. ERT is most helpful when you have established the basics of the geology and then extend and refine your interpretation spatially and temporally (w/ time-lapse surveys).

MODFLOW may not be suitable if unsaturated zone process is important to you. It is primarily a groundwater simulator and it uses a recharge coefficient to account for unsaturated zone process, instead of the Richards equation (although there is the VSF package). The most popular Richards equation simulator for the unsaturated zone is HYDRUS but there are many more codes out there.

Hope this helps!

from geoelcetrical sections we can infer subsurface geology with respect the appearant resistivity values and how many layers are there with the help of boreholes data if available (caliperation)

the most important things we can infer the saturated zone ( low resistance )

but I think GOCD software is better