Statistical quality control method for automated water flow measurements in concrete dam foundation drainage systems

Abstract

Seepage through the foundation is a relevant condition for the structural assessment of concrete dams. The knowledge of the water flow measured in the drainage system installed to reduce the uplift pressure in a dam's foundation is, therefore, a main issue in the safety control of concrete dams. Monitoring systems include measuring devices to determine the water collected from drains and weirs in order to evaluate the amount of water that flows through the dam. In most large concrete dams, both manual and automated water flow measurements are possible. This paper proposes a statistical quality control method for automatic measuring systems based on simultaneous manual water flow measurements and the knowledge of the corresponding measurement uncertainties. Experimental tests performed in a weir of a Portuguese concrete dam are described and paired water flow estimates and corresponding measurement uncertainties are presented and applied to the proposed method. The results of this study show that the method allows statistical quality control of automated water flow measurement systems applied in concrete dam drainage systems.