I too am in the irrigation and plumbing business and have given this alot of thought in the past. The big problem for most tracks is the water supply. Not alot of places have the pressure or volume to run those bigger sprinkler heads all at once like a golf course does. So by the time you break them up into zones and wait for them to go trough the cycle you could have watered with a few hoses. Also, unless your track is fairly flat you are gonna have problems with coverage because of the elevation change and the jumps. One side of a jump will get soaked and shield the other side. Marcus, I think has the best idea if funds were not an issue as an overhead system would simulate rain and cover quickly and evenly. With that ruled out though I think a good track team with hoses is the best way to water.