Calibration of tipping bucket hyetographs

Abstract

The Institute for Hydraulics and Hydrology of the Technical University Graz, Austria operates two hydrological observation nets - one in the area of Eastern Styria and the other one in the city of Graz. Precipitation, meteorological and runoff data are collected.

Comparative measurements of the tipping bucket hyetographs have shown the deviation between the recorded and the real precipitation intensity. Aim of the presented project was to get calibration curves for all tested precipitation gauges.

The following steps were necessary:

a) Development of a micro processor controlled calibration system. The calibration instrument is able to record a series of measurements for determining calibration factors.

b) Development of a control software for the calibration device, that is able to take over the menu control with a laptop and store the determined values in an MS Excel worksheet. These values are used for calculating correction values and to display them in an adequate graphical way.

c) Development of a practicable application software for correction of the measured precipitation data.

The determined correction factors permit to consider the source of failure (e.g. location, ageing and wear of the material) and make available improved hydrological data.