NATIONAL DATABASE FOR MITIGATIVE MEASURES AGAINST RAPID GRAVITY MASS FLOWS AND ROCK FALLS

2 Now at Shell of Norway ABSTRACT: Mitigation measures against natural catastrophes, such as rapid gravity mass flows and rock falls, have been built in Norway for centuries. Over the last few decades the number of new constructions has been increasing due to stricter safety requirements and increased population in exposed areas. The Norwegian Geotechnical Institute (NGI) initiated a project in early 2011 to investigate the condition of mitigation measures, and to suggest improved methods for maintaining them. Our study revealed that most mitigation measures were left without any plans for control or maintenance. Additional field work also revealed that many of the structures required repairs. An increasing number of mitigation measures are being built every year, and there is an urgent need to establish plans for controlling and maintaining these measures in the near future. For such plans to be established, we found that a system for maintaining information about the measures is required. The system should involve the following processes: 1) acquiring consistent information about all mitigation measures, both planned and built, 2) registering the need for maintenance for each measure an d 3) making a plan for future maintenance and/or rebuilding of structures. Based on these findings, we established a GIS-based pilot database in 2011, and started the initial registration of known measures. This pilot system was successful, and we are continuing the work throughout 2012. The results have been presented and discussed with three governmental agencies in charge of mitigation measures against different natural hazards, which has allowed the work to be continued in the NIFS project.