TR(BR)-22/99-2000 : Field testing of weighing rain gauge

Abstract

Reliable and accurate measurement of rainfall is an essential requirement in hydrological studies. For automated recording of rainfall data, tipping bucket rain gauges are generally used. It has been reported that the tipping bucket mechanism of such rain gauges frequently malfunctions and gives erroneous data, especially during high intensity rainstorms. Weighing type rain gauges are considered worldwide as accurate and reliable. With the weighing rain gauges, the ability to measure rainfall over very short time intervals (e.g. minutes) offers an advantage not generally available with conventional rain gauges.

Development and testing of a weighing rain gauge, using components and systems available indigenously, is reported. With the reported rain gauge, the total amount of rainfall can be measured continuously, and the rainfall intensity can be derived. Rainfall observations from the reported WRG were compared with that of the other standard rain gauges, e.g. SRRG and ORG, at a site in Roorkee (India) The instrument would require further field testing under different rain spells of sizeable magnitudes and duration. The results of the limited field testing carried out during 1999-2000 are presented in the report.