Calculate the headloss through a filter bed consisting of 30.0 in. of stratified sand with the gradation given below. Assume a filtration rate of 5.0 gpm/ft2, a clean bed porosity of 0.42 and a temperature of 40i F.

U.S. Sieve Number 50

40 30 20 18 16

Sieve Opening (mm) 0.297

0.420 0.590 0.840 1.000 1.190

Percent Passing (by wt.) 0.10

6.50 22.00 76.00 90.00 98.00