The photo above shows the Spray Nozzle.
It connects to 1.5 inch hose via hose clamps, It delivers 7 gpm at 100 psi.
The spray nozzles are spaced 10 feet apart.
The hinged lid of the cradle is placed at ground level. The 2 holes in the front side of cradle have nothing to do with water. They prevent the nozzle from rotating by using zip ties if that is necessary.
The cradle supports the weight of an auto.
The hinged top of the cradle is set at ground level.