DATA & METHODS
The requisite data required for the study such as soil flow properties,
groundwater abstraction, rainfall, geological formation, and observation
wells was obtained from concerned Government Departments & Agencies.
The initial groundwater heads were taken from 32 boreholes drilled in
2011 by the ‘Punjab Mines & Mineral Department’ for mining purposes.
These boreholes also provide information regarding subsurface geology of
the soil layers. The formations exposed near Katas and its vicinity
indicate the presence of alluvium clay mixed with sand gravel having a
thickness of 05 m from the top surface. The sand/gravel exists from 05
to 100 m and beyond 100 m shale is encountered. The rainfall data for
the last 10 years (2010-2020) was used for model development. One
hundred forty-nine agriculture tube wells abstracting 59,174
m3/day, 15 domestic water supply schemes abstracting
6,242 m3/day, and 27 industrial tube wells abstracting
10,284 m3/day are operational in the study area.
Groundwater Flow Model
Development
Across the globe, there are many groundwater simulation platforms/ flow
models such as AQUA3D, FLOWPATH, GFLOW, GMS, PROCESSING MODFLOW (PMWIN),
SEAWAT, MODPATH, etc., but MODFLOW is the most commonly used
three-dimensional numerical groundwater flow model developed originally
by USGS (McDonald & Harbaugh, 1988).
MODFLOW is based on partial differential finite difference schemes that
simulate three-dimensional groundwater flow for the solution of the
governing mathematical flow equations
(Harbaugh, Banta, Hill, & McDonald,
2000). It has more advantages like facilities for easy data input,
compatibility with other software, availability of source code, output
visualization in two & three-dimensions, worldwide experience, and
relatively low price (Kumar, 2002). The
finite difference-based MODFLOW uses a three-dimensional flow equation
(Equation 1) combining with Darcy’s Law and the principle of
conservation of mass (Kumar, 2013).