ABSTRACT
Measurement of hydrological parameters dates back many centuries. In early times daily readings from single water level gauges were taken for the benefit of agriculture or navigation. Later on the first hydrological networks were set up, in which various parameters were measured (water levels, discharges and rainfall) which were related to one another. Nowadays hydrological networks are installed in large and small watersheds, whereas the field data are collected automatically and transmitted by telemetry systems. In addition to the usual water quantity data, in many cases water quality parameters (oxygen, pH, nutrients and others) are measured as well.
