Determines the evaporation rate by measuring changing water level in an evaporation pan. The gauge is intended for use with a National Weather Service, class A pan.

The instrument consists of a float, chain, and counterweight attached to a precision 1000-ohm potentiometer mounted through a sprocket assembly in a weatherproof housing. The triangular base plate is equipped with three leveling screws and a bubble level indicator. The potentiometer produces a resistance output proportional to the position of the float which can be monitored on site using a data logger or monitored remotely by telemetry equipment.

Full Details Here