Gaging stations are facilities used by hydrologists to automatically monitor streams, wells, lakes, canals, reservoirs and or other water bodies. Instruments at these stations collect information such as water height, discharge, water chemistry and water temperature.
Some have a Wire Weight gage (such as this one). Permanently mounted on the side of a bridge a wire weight gage has a weight, a reel of wire, and a manual crank. The weight is lowered until it touches the water. A calibrated spool accurately determines how much wire was required for the weight to reach the water. This number is used to calculate the stage of the stream.
The cache is not on the banks of the river, but it is close by. As such, please keep an eye on all young children. Do not touch any of the equipment (the cache is far enough away from all equipment that you have no need to be even near it). Finally, the land to the south is private property (as marked by the signs) do not trespass.