Description

6529-1: The Evaporation Monitoring System measures how much water evaporates from a Class A evaporation pan by measuring the water level in an adjoining stillwell. The stillwell reduces fluctuations in the pan’s water level caused by wind.

6529-2: Semiautomatic Evaporation System records water level using a modified Model 6541C-31-C Water Level Instrument that is fitted with a 100mm circumference pulley. This provides measurements with a resolution of 0.5mm. An optional thermistor probe float assembly may be purchased to rest on the surface of the water in the pan to obtain a surface temperature reading.
WLI also has an LCD that shows the current depth in the evaporation pan. The stillwell, the measurement system, and water level instrument including an LCD and micrologger are housed in an aluminium enclosure.

6529-3: Automatic Evaporation System is designed to operate for long periods without maintenance. It is similar to the 6529-2 but automatically refills and discharges water from the evaporation pan.
The 6529-3 operates an evaporation pan and records evaporation and rainfall data. The instrument is normally supplied as a complete package with a US Class A evaporation pan and all installation fittings. Still, it can be connected to any other type of pan.
The 6529-3 system is designed to operate for long periods without maintenance. The water level instrument and data logger operate for one year from internal batteries and water level control system, refill and discharge of water from the evaporation pan, is solar-powered. The water supply to refill the evaporation pan is provided by the user from a tank or a reticulated water supply pipe. Rainfall removed from the pan can be recycled if required.
The datalogger included with the unit is fully programmable and has all the STARLOG features. Some of these are event and time interval recording, programmable measurement and recording intervals, signal processing such as average, max, min and computations, including flow conversions and rating tables.
A water temperature sensor and a range of weather sensors can be added to the system to identify the relationship between pan evaporation and site conditions. These are required for evaporation and evapotranspiration studies and modelling.
The traditional micrologger can be replaced with the Unidata Neon Remote Terminal that can use ether cellular or satellite communication links to transmit the logged data to a central Neon server, and the data can be then viewed on a standard web browser, in near real-time.