Question $4(20$ marks$)$:

A well is to be developed in an unconfined aquifer as shown in Figure $2.$ You may assume that approximately $5$ km from the well, conditions are such that the piezometric levels are constant at an elevation $6$ m above the impermeable level as shown. The anisotropic aquifer material consists of a $4-$m thick sandy soil overlaying a $4-$m thick gravel with saturated hydraulic conductivities of $0\mathrm{.}05$ and $0\mathrm{.}20c\frac{m}{s},$ respectively.

a$)(10$ marks$)$ Calculate equivalent horizontal $K_x$ and vertical $K_y$ hydraulic conductivities of the anisotropic aquifer.

b$)(10$ marks$)$ What drawdown, at distances of $10$ and $100m$ from the pumping well, can be expected at a uniform pumping rate of $50,000\frac{L}{?}$ day?