3 Exercises
Exercise 1) A sand filter has its base at 0 meters and is 10 meters high. A plan view, to-scale diagram of it is shown below. These features are the same on every horizontal slice. There is an impermeable pillar in the center of the filter. Reservoirs on the left and right are separated from the sand by a screen that only crosses a portion of the reservoir wall. The hydraulic head in the inlet reservoir on the left is 20 m and the outlet reservoir on the right is 12 m. Hydraulic conductivity of the sand is: K=1×10-3 m/s.
Draw and label a flow net.
Calculate the discharge through the system using units of cubic meters and seconds.
What is the hydraulic head in meters at the location of the * at the top of the tank?
What is the pressure head in meters at that location?
Click here for the solution to Exercise 1
Exercise 2) An impermeable sheet pile is driven 5 m into the ground and extends 22 m in the direction perpendicular to the figure below. The sheet pile impounds 10 m of standing water on the left. Assume that the impounded water can seep through the underlying material with a hydraulic conductivity of 2 m/d to discharge at the ground surface on the right of the sheet pile.
What is the volumetric flow rate under the sheet pile wall?
Click here for the solution to Exercise 2
Exercise 3) An earth embankment retains water as shown in the diagram below. The earth material has a hydraulic conductivity of 0.2 m/d resting on an impermeable bed. The dam extends 28 m in the direction perpendicular to the diagram, and is capped with impermeable material such that water is prevented from infiltrating the surface of the dam. The upgradient reservoir has an elevation of 5.3 m. The gravel drain is keyed into the top of the impermeable bed on the right.
Draw and label a flow net of the system.
Calculate the discharge through the system using units of cubic meters and seconds.
Click here for the solution to Exercise 3
Exercise 4) A portion of an anisotropic (Kx=225 m/d and Ky = 9 m/d), 100 m thick, confined aquifer is shown in map-view in the diagram below. The area is 281 km long and 144 km wide, and bounded by impermeable boundaries on the north and south. An impermeable material cuts through the aquifer as shown by the black zone. Head is measured at 1000 m on the west boundary, 900 m on the northeast boundary and 800 m on the southeast boundary.
Draw and label a flow net of the system.
Calculate the discharge through the system using units of cubic meters and seconds.
