Compute the infiltration rate incheshour if 01 gal of water

Compute the infiltration rate (inches/hour) if 0.1 gal of water moves downward from the central ring of 10-in. diameter double-ring infiltrometer in 30 minutes (1 gal = 231 in.^3)

Solution

If 0.1 gal of water moves downward from central ring in 30 minutes then 0.2 gal goes downward in an hour. This means 0.2gal/hour is volume flow rate through the ring. Infiltration rate in inches/hour = 0.2*231/3.14*10*10 = 0.147 inches/hour.( where 3.14*10*10 = crossection area through which it is flowing)