The implications of climate change effects on the response parameters of concrete arch dams with respect to anomaly detection

Abstract

Anomaly detection is of great significance in dam safety management. There is an abundance of literature looking at anomaly detection, but they have not accounted for the effects of climate change. Research has shown that climate change will affect the water temperatures (loads) acting of concrete arch dams by 2050, the change in the water temperature load will influence the response parameters of the dam. These effects have not been accounted for by any literature into anomaly detection of arch dams for present day and in the future. The aim of this article was to predict the deformations (response parameter) of Roode Elsberg dam deformations using the risk-based framework, with an account to daily operational behaviour of the dam and with respect to the South African climate change scenarios by mid-century, 2053 using nonparametric machine learning model and look at the implications of the results with respect to anomaly detection of arch dams. The variables used were the ambient temperature, water temperature, water level as loads and the radial deformations as the systems response. There were three water level scenarios that were used, the recorded water level (RWL) scenario, the full dam steady state (FSS) and the low-level steady state (LSS). RWL had water temperatures available for 2012-2017 and the water temperatures for 2048-2053, with water temperatures for the FSS and the LSS for 2012-2017 and 2048-2053 were predicted. Climate change models MIROC-ESM-CHEM at RCP4.5 and ACCESS1-0 at RCP8.5 were used as the warmer and the hotter model, respectively. SGBM was chosen as the best model for making prediction at root mean square error (RMSE) of 0.0019. Roode Elsberg radial deformations are expected to move upstream during winter as a subset of the three water level scenarios. The precipitation of Roode Elsberg catchment is expected to decrease therefore the highest probability of occurrence of seasonal rainfalls matching the LSS. Warmer (<3°C) and drier conditions will cause Roode Elsberg dam to move upstream during winter and spring between 2012-2017 and 2048-2053, while hotter (>3°C) and drier conditions will cause the dam to move upstream during winter and spring with slight upstream movement in autumn.