Some challenges in hydrometry

Abstract

Hydrometry has always been an important branch in hydrology. Even so, the quality of streamflow data might not have evolved in accordance with the advances in hydrological sciences. A too large uncertainty in published data is still a challenge in hydrometry. Hydrometric field work is a diverse profession. Technical equipment and personnel competence are usually in accordance with accepted standards. Hence, there are no technical or practical reasons that should indicate that it is impossible to achieve accurate data for a particular gauging station, given that it is reasonably located in the river channel. This short note argues that two main reasons for a too large uncertainty in published data are too comprehensive hydrometric networks and no criteria for accuracy of published data. It is also argued that the chief uncertainty factor in rating curves is extrapolation uncertainty. A short description of a project in Statkraft that has been launched to minimize extrapolation of rating curves in the network owned by the company is also given.