A long lake is located in a range of hills. Beneath the lake there is a weathered dyke inclined at 60o to the horizontal which connects to a gravel aquifer, a section through which is shown in Figure 3. The surrounding rock mass may be regarded as impermeable. Tests on gravel aquifer indicate that it has a coefficient of permeability of 0.15m/s and flow measurement at the aquifer outlet spring gave a value of 0.015 m3 /s per meter run
a) Determine the coefficient of permeability of the weathered dyke.
b) An inclined borehole is to be installed as shown in the figure. Determine the RL of the water level in the borehole a long time after drilling the hole.

 

RL: 100 m 2m Weathered dyke 5m 60 RL: 90 m RL: 55 m Inclined bore hole Gravel aquifer 120m RL: 40 m Spring outlet