HYDROLOGICAL DATA MONITORING FOR URBAN STORMWATER DRAINAGE SYSTEMS

Abstract

Good quality hydrologic data are required to develop and calibrate simulation models, which are often used to plan, design and upgrade urban stormwater drainage systems. These good quality data can be obtained from a successful data collection program. This paper describes the issues that should be considered in conducting such a successful and cost-effective hydrologic data monitoring program. The issues addressed include considerations given in the selection of suitable monitoring sites, the selection of appropriate measuring equipment and the calibration and installation of the measuring equipment. Furthermore, the techniques that were used to test the accuracy and consistency of the measured data are also outlined. In addition to these issues, the effects of rainfall measuring resolution of pluviometers and data logging interval of flowmeters on the accuracy of rainfall and stormwater runoff data, and computer modelling results were investigated. These investigations revealed that tipping bucket resolutions up to 0.5mm would give reasonably accurate results in urban stormwater modelling. A two-minute data logging interval was found to be suitable for flow data monitoring. The results of the investigations also suggest that a combination of low cost simple flow measurements and limited high cost sophisticated measurements can be used to reduce the data acquisition cost without compromising the accuracy of flow hydrographs measured in stormwater conduits.