A failure in a hydro project under construction hit the news headlines earlier this month. In China, a landslide in the southeastern Fujian province cost the lives of 34 people.
The landslide was triggered by heavy rain and hit a hydroelectric power station that was under construction in Fujian’s Taining County. The government has blamed breaches of construction safety rules for that disaster and a number of officials have been arrested. This is the latest accident of this kind and questions have been raised about China’s industrial safety standards and lack of oversight over years of rapid economic growth. Earlier in December, a landslide in the southern city of Shenzhen buried 77 people.
Post a failure event in the construction insurance industry, the same questions are raised. Was it foreseeable or unforeseen? Was there a proper risk assessment carried out and could the failure and its consequences have been avoided?
For hydro projects, particular attention must be paid to the portal areas of the tunnels, including headrace, pressure and construction adits, and to the location of the dams and the powerhouses. It is imperative that a landslide hazard map is prepared in the design and construction stages, indicating the hazard impact and likelihood, making use of all the available information, i.e. from geological maps and aerial photographs to geophysical campaigns and intrusive ground investigations. Detailed ground investigations may be necessary for assessment of small areas and specific sites during construction. Based on a study as such, an assessment of the risk can be performed and a decision can be drawn on implementing (or not) particular landslide risk mitigation measures. The hazards can range from catastrophic and dramatic effects to the barely perceptible but persistent processes such as slow creep movements and localised rockfall events. The areas that will be assessed as of major or critical risk must be avoided during optimization of the different scheme layouts. Those rated as moderate risk should mostly be avoided, but where areas rated as moderate risk are unavoidable, mitigation or monitoring measures shall be designed and put in place as part of the detailed design. Landslide hazards resulting from seismic activity must be identified as well since the seismicity will act as a trigger increasing the likelihood of landslide events.
A proactive and targeted risk engineering and management approach and attitude can highly improve the situation with significant gains for the insurance market and benefits for the involved project stakeholders. The importance and benefits of such risk management exercises in the insurance industry have been qualitatively outlined in a WTC2014 paper, which I was glad to co-author.
A proactive risk engineering management attitude and probabilistic approaches can efficiently contribute in reducing the size and frequency of major incidents, especially by integrating all important lessons learnt from past years in a continuous live updating process.
