The sensing devices are the conventional Hydrological Services' pressure sensing unit, the floatwell system, the Druck pressure transducer, the Vega 72-1 ultrasonic transducer and the Zwarts Electro-magnetic transducer.

The logging systems consist of the MHL solid state floatwell and pressure recording systems, the Hydromace TRS and 2000 and the Datataker 50 data logger. For the solid state floatwell system developed at the MHL, the water level is sensed by a float connected to an optical shaft encoder which is read every 10 seconds for 160 seconds, averaged then stored on the quarter hour Eastern Standard Time. This data is then stored by a solid state recorder which can retain up to a maximum of six months of data. The data is either returned to the Laboratory at the end of this period or downloaded in the field by a portable computer.

Once data has been transferred onto the MHL Alpha Server 1200 computer, a suite of programs runs routines to ensure the data is acceptable for inclusion in the database. At this stage water level data is available for external users. Only hourly water level data is available on-line. The raw data files, which are copied and stored on magnetic tape and optical disk, consist of either the one or fifteen minute files. This data can be loaded onto the computer on request.