The minimum thickness of the drainage layer of a landfill cover system is dependent on the hydraulic properties as well as the geometrical configuration of the layer. A rectangular landfill in the New England area is 175 m in width, and sloped at the uniform angle of 75 degrees. Its cover system includes a drainage layer constructed of clean, medium sand (Ks = 10^-2 cm/s). The results of a study of stormwater percolation at this site is presented below.
A. For this landfill, what is the relationship between precipitation rate and then resulting rise in water level within the drainage layer? Display your analysis graphically, corresponding to a minimum of the five rainfall intensities of magnitude 1-5".
B. If the angle of the landfill was increased to 7.8 degrees, what would be the corresponding relationship? What if the slope was reduced to 7.2 degrees?
Rainfall Intensity (in) Maximum Infiltration (cm/s)
0.5 3.430 X 10^-8
1.7 5.370 X 10^-7
3.3 2.104 X 10^-5
5.2 1.640 X 10^-3