Problem $4$

The figure below shows a lake which lies above a limestone aquifer $($leaky confined aquifer$).$ When a monitoring well is drilled in the aquifer $($very close to the lake$)$ the water in the well rises $100ft$ above mean sea level. Assume that the average water level in the lake during the winter is constant at $110ft$ above mean sea level $($for $7$ months$)$ and during the summer $108ft$ above mean sea level $($for $5$ months$).$

a$)$ Determine the direction of flow through the silt and clay layers. Is this lake recharging the aquifer or the opposite? Support your answer.

b$)$ If this lake is the size of Folsom Lake, calculate how many acre$-$feet of water the aquifer gains $($or losses$)$ in one year through the silt and clay layers.

You can obtain any necessary parameter values from the literature $($i$.$e$.$ hydraulic conductivity for slit and clay or any other property needed$).$