Most rural fire departments don't have the luxury of having pressurized fire mains. The trucks have to carry their water with them or draft the water from a brook, a pond or an underground cistern. This is where suction lines with a box strainer or a dry hydrant come into play. A dry hydrant is basically an empty standpipe in the pond or underground cistern with a fitting on the end to attach the suction lines ( a misnomer) to the fire truck. When the pump operator on the truck starts the pump he'll pull the primer which causes a negative pressure (vacuum) in the standpipe and suction hoses and pump. Atmospheric pressure pushes down on you, me, the water in the pond and dry hydrant, which in turn pushes the water through the vacuum in the line to the pump on the truck. A perfect vacuum is measured at 28 inches in a column of mercury, which means theoretically a pumper fire truck should be able to draft water from 28 ft. below the truck pump. For all practical purposes because of friction from the hoses and fittings the maximum it can do is 25 ft.
To find the cache, go from the cache at 36 degrees magnetic at 112 ft.to the waypoint.