Wells equally spaced around the perimeter of a 30 m wide circular arrangement must lower the water table by a minimum of 4.5 m below the existing groundwater table. The

water-bearing stratum of alternative sandy layers (see profile below) is under laid by an impermeable layer. Well radii are 0.15 m. Find the minimum number of wells required to satisfy the drawdown condition. Assume no free discharge height and a radius of influence of 20 m.