Sediment Connectivity in Proglacial Areas

Sediment connectivity is an emerging property of geomorphic systems and has become a key issue in research on geomorphic processes and sediment cascades. Sediment connectivity represents coupling relationships between system compartments and elementary units, and thus its understanding has important implications for the behaviour of hydro-geomorphic systems. The investigation and characterization of sediment connectivity and its evolution through time are of particular importance in proglacial areas and high-mountain environments since they are subject to intense morphodynamics and frequent changes in their structure and subsequent variations in sediment connectivity. This chapter aims to review the state of the art of sediment connectivity in proglacial and high-mountain environments studies, provides a synopsis of the most widespread landforms in mountain headwater catchments and describes their role with respect to coarse sediment connectivity. In addition, a section of the chapter is dedicated to the description of a recently developed topography-based sediment connectivity index. An example application to two contrasting alpine glacier forefields shows the effectiveness of this index for investigating and interpreting spatial patterns of connectivity in high-mountain catchments. Finally, we sketch avenues for future research regarding sediment connectivity (not only) in proglacial systems

An integrated socio-environmental framework for glacier hazard management and climate change adaptation: lessons from Lake 513, Cordillera Blanca, Peru

Glacier hazards threaten societies in mountain regions worldwide. Glacial lake outburst floods (GLOFs) pose risks to exposed and vulnerable populations and can be linked in part to long-term post-Little Ice Age climate change because precariously dammed glacial lakes sometimes formed as glaciers generally retreated after the mid-1800s. This paper provides an interdisciplinary and historical analysis of 40 years of glacier hazard management on Mount Hualcán, at glacial Lake 513, and in the city of Carhuaz in Peru’s Cordillera Blanca mountain range. The case study examines attempted hazard zoning, glacial lake evolution and monitoring, and emergency engineering projects to drain Lake 513. It also analyzes the 11 April 2010 Hualcán rock-ice avalanche that triggered a Lake 513 GLOF; we offer both a scientific assessment of the possible role of temperature on slope stability and a GIS spatial analysis of human impacts. Qualitative historical analysis of glacier hazard management since 1970 allows us to identify and explain why certain actions and policies to reduce risk were implemented or omitted. We extrapolate these case-specific variables to generate a broader socio-environmental framework identifying factors that can facilitate or impede disaster risk reduction and climate change adaptation. Facilitating factors are technical capacity, disaster events with visible hazards, institutional support, committed individuals, and international involvement. Impediments include divergent risk perceptions, imposed government policies, institutional instability, knowledge disparities, and invisible hazards. This framework emerges from an empirical analysis of a coupled social-ecological system and offers a holistic approach for integrating disaster risk reduction and climate change adaptation