Hello Pooja, following Mr ...

Hello Pooja, following Mr Nithin's very brief description, may I expand slightly on his suggestion:

the surface area of the catchment will normally be approximately the surface area of the surface runoff catchment.  This means estimating the catchment boundaries based on the contours.  You may need to modify this when you look at a geological map and identify dykes and faults which may either reduce or expand the size of your catchment, as well as stream flows passing through the catchment from neighboring sub-catchments.

also try to identify boundary issues of the catchment - e.g. which boundaries are confined and which are unconfined (allowing leakage out of the aquifer).

secondly determining the percolation coefficient is a major challenge as it is likely to vary across the catchment, and will also be different depending on the antecedent moisture content of the catchment.  This means that you may need to sub-divide your catchment into areas for which the percolation coefficient is more or less uniform (e.g. rocky areas, grassland, natural vegetation of trees and shrubs, cultivated land, urban land, etc.  In dry years the percolation will only initiate once sufficient rainfall has occurred to moisten the underlying soil layers, and hence use of only the average annual rainfall will give you an average infiltration, but not a probability distribution to determine your acceptable pumping rate.

Note that pumping tests evaluate the permeability of the aquifer, but not the recharge rate.