BOULDER: Accounting for BOUlders in Landslide-flood Disaster Evaluation and Resilience

Landslides and floods are globally occurring natural hazards that pose a significant threat to human life and sustainable development. The most severe losses due to landslides occur in the less economically developed countries of Asia and South America, particularly in those with mountainous topography, earthquakes and monsoonal climates. Landslides and rockfalls in these regions often detach fractured bedrock and deliver large boulders downslope that block roads, destroy buildings and kill people. On entering the river channel network, boulders may be bulldozed by large floods and block hydropower infrastructure, jeopardizing electricity supply and the economy. Thus, boulders may cause a cascade of hazards. This project addresses specific landslide and flood risk management problems brought to our attention by stakeholders impacted by boulders in the Upper Bhote Koshi catchment in Nepal, one of the most landslide and flood-prone countries in the world. This project also addresses a lack of data and scientific understanding of (i) boulder production on hillslopes (e.g. by landslides), (ii) boulder transport in floods. In this two year project, an inter-disciplinary team of researchers will work closely with project partners to (1) map boulders and investigate the controls on boulder production on hillslopes by landslides and rockfalls, (2) develop a new real-time GPS boulder tracking system with which to improve understanding of boulder movement in floods and monitor hazardous boulders (3) engage with stakeholders to incorporate findings into disaster management plans and ultimately to increase resilience to landslide and flood hazards.

The project will focus on the Upper Bhote Koshi (UBK) catchment to the north east of Kathmandu, Nepal, and has been designed with specific end users in mind in the UBK that are dealing with boulder hazards related to landslide and floods. This area is particularly vulnerable to boulder hazards as it is the main road link between Nepal and China and contains several major hydroelectric power plants including the Upper Bhote Koshi Hydroelectric Power plant (UBKHEP). The catchment encapsulates the multitude of natural hazards faced by Nepal. In 2015 the catchment was shaken by the Gorkha earthquake generating some of the highest densities of landsliding anywhere in Nepal. In July 2016, a complex monsoon flash flood entrained extremely large boulders (>8 m) some of which became jammed in the sluice gates of the UBKHEP culminating in more than $110 m damage to the power station. The power station remains closed resulting in lost revenue and compromising Nepal's energy supply. As the power company rebuilds and a further hydroelectric power station is built just downstream, it will be vital to properly account for future boulder hazards in landslide and floods.

The project brings together an interdisciplinary team of researchers based in the UK, Germany and Nepal with several project partners that have helped to define the problems that this project will address. The boulder hazard map and boulder tracking system developed in this research will help make the Bhote Koshi Power Company and wider hydropower industry more resilient to landslide and flood hazards. The research will also benefit organizations managing transport infrastructure and communities living on steep, landslide prone hillslopes in the Bhote Koshi. We will hold two project workshops bringing together project partners and relevant stakeholders from industry, local communities and government institutions with the help of Practical Action Consulting Nepal, to research boulder hazard perception and enhance uptake of this research into risk management practice at local and national governance level and ultimately to aid development in Nepal and South Asia.

Ultimately, we envisage the proposed research will have global impact regarding best practice for the assessment and management of landslide and flood hazards, through enhancing understanding of boulder production and transport and accounting for boulders transported within landslides and floods in landslide and flood hazard assessment for the first time. More immediately, the research will benefit a range of stakeholders in the Bhote Koshi catchment in Nepal. We will also work closely with project partners and stakeholders to scale up the research impact to the wider region of Nepal and south Asia.

The research will directly benefit the Bhote Koshi Power Company (BKPC) whose hydroelectric power station was damaged by large boulders in a flash flood in July 2016. We will meet with the BKPC during our first field visit and will design our real-time boulder monitoring system in close coordination with them. At the end of the project we will share this system with BKPC access enabling them to monitor boulders upstream of the power station. We will also work with them to integrate boulder hazards into their disaster management plan as they rebuild their power plant. Through Reynolds International Ltd, one of our project partners, our knowledge of boulder hazards and boulder tracking system produced in this research will be communicated to government agencies such as the Departments of Hydrology and Meteorology and Geology and Mines. By increasing preparedness and resilience of the BKPC and wider hydropower industry to future flood hazards, the research will also have impact on communities that rely on electricity generated by this industry.

The research will also benefit transport infrastructure and users of transport infrastructure in the catchment through quantifying risks posed by boulders to roads and bridges. Bennett has already engaged with Project Partner, Michael Whitworth, AECOM, who has for the past 3 years been investigating the impact of both earthquake and monsoon induced landslides on communities and transport infrastructure in Nepal. We will coordinate with Whitworth to discuss ways in which the proposed research could contribute to efforts by AECOM to improve the resilience of the transport infrastructure in the UBK. The research will also benefit communities through sharing maps of boulder hazards and making communities aware of the particular risks posed by boulders with the help of PAC and Scott Wilson Nepal. We will also research the perception of boulder hazards amongst communities. Through these efforts, we will explore how to increase resilience of people to large boulders within landslide and rockfall masses.

This collaborative project includes scientists from different disciplines and different nations (UK, Germany and Nepal) with an NGO, industry partners and stakeholders and takes advantage of new technology tested at UEA. We see it as a clear advantage that PAC are already involved in two other UK research council projects in Nepal, including a SHEAR project that focuses on other aspects of floods and landslides in Nepal and India, and thus that ideas will inevitably be shared between projects leading to wider reaching and unforeseen impacts. Furthermore, Bennett has already discussed proposed research with Project Partner GFZ Potsdam and discussed ways in which the proposed research would complement ongoing research in the UBK. Thus, we envisage this project catalysing further collaborative research into landslide and flood hazards in the UBK and across the wider region with the ultimate aim of increasing resilience to these hazards. Through Practical Action Consulting and RIL, our research will also be communicated with relevant government agencies like Department of Soil Conservation and Watershed Management, and non-government agencies to translate these findings into wider policy making regarding boulder hazard integration in flood and landslide risk management in Nepal.