Right !! they say that if you put an empty tin can onto the ground and either measure the rain or sprinkler in the can.if its an inch deep then youve had an inch of rain.An inch is helluva lot as when I was trying to gauge this after installin sprinklers it took ages to get 1/4 inch of water measured and the turf was saturated.
stuart
www.simplesprinklers.bravehost.com