Floods remain among the most widespread and impactful natural disasters, particularly in mountainous areas. Mountains represent areas of complex terrain, high relief, large precipitation variability, limited accessibility, and scarcity of hydrometeorological and pedological information. Hence, floods in mountainous areas present unique challenges in flood forecasting, response, and recovery.
Flood generation processes associated with localized, extreme events, such as cloudbursts, landslides, and glacial lake outbursts, are poorly understood. Furthermore, issues with remoteness, limited communication networks, and weak or inadequately supported governance structures make it difficult to establish effective forecasting and response systems in mountain areas. The result is greater flood vulnerability and increased potential for loss of life. Because mountain areas are particularly sensitive to climate change, their flood vulnerability will increase as changing precipitation, temperature, and snow and glacier extent affect the frequency and severity of many processes that trigger floods in mountains.
To identify the key challenges and find solutions for reducing flood losses in mountain areas, an international group of hydrologists, engineers, and managers convened in mid-February in Folsom, Calif. Funded by the Indo-U.S. Science and Technology Forum, the goal of the workshop was to bring together scientists and engineers from academia, industry, and government agencies in the United States and India for a discussion of ideas, techniques, and experiences.
Technical sessions focused on different facets of flood generation in mountain forecasting, hazard modeling, and management. Discussions and presentations centered on identifying the unique hydrometeorological, geological, socioeconomic, and governance conditions associated with flooding in mountainous areas and determining the key scientific and management needs for decreasing the potential of flood hazards turning into a flood disaster.
Outcomes included the identification of critical but unreported knowledge gaps in understanding atmospheric processes and their interactions with the mountain landscape. These gaps include the role of orography in driving extreme precipitation and the convergence of large-scale monsoon cells in the atmosphere. In addition, the group identified instrumentation needs specific to mountainous areas for advancing knowledge on flood generation, including specialized technologies for improved and wider monitoring of hillslopes, hydrometeorology, hydraulics, and glacial lakes.
Participants also specified five management principles that address the unique challenges in reducing flood losses in mountains and summarized case studies in which those principles were successfully applied. For example, one principle argues for implementation of mitigation measures that are effective under limited or short forecasting times, including nonstructural flood infrastructure, land use planning and regulation, and early warning systems. A second principle calls for training local people and officials in disaster planning, response, and recovery. All principles are based on the premise that the forecasting, mitigation, and communication of flood hazards require additional efforts in mountain areas.
Data, details, and implications of the workshop are analyzed and reviewed in three manuscripts on the topics of mountain flood processes, forecasting, and management. These papers are currently in the final stages of preparation.
—Desirée Tullos, Oregon State University, Corvallis; email: [email protected]; and Sharad Kumar Jain, National Institute of Hydrology, Roorkee, India
Citation: Tullos, D., and S. K. Jain (2015), Addressing challenges of mitigating flood risk in mountain areas, Eos, 96, doi:10.1029/2015EO030887. Published on 8 June 2015.