Landslide Sediment Connectivity to Stream Networks in a Highly Cultivated Tropical Landscape

Keywords: Hillslope debris flow, Landslides, Runout distance, Catchment connectivity, Puerto Rico, Hurricane María
Abstract Type: Poster Abstract

Abstract

As a result of climate change, the Caribbean is expected to see an increase in the frequency and duration of drought periods as well as the frequency and magnitude of tropical cyclones. High intensity tropical storms are capable of displacing large volumes of sediment from hillslopes to downstream water reservoirs through mass wasting. In Puerto Rico, these factors contribute to reservoir sedimentation, which likely induces strain to water availability for agricultural irrigation, domestic water supply, and hydroelectric power production. The current literature on modeling landslide runout lengths has been well researched in the uncultivated temperate mountains of Idaho and Switzerland, using in-situ data collection techniques to classify and measure downslope runout lengths. However, little research evaluating landslide runout lengths currently exists in highly cultivated wet subtropical/tropical hillslopes settings using high resolution (1m) digital elevation models, GIS, and remote sensing technology to classify and measure travel distance of landslides and degree of sediment connectivity with stream networks. Using a database of landslides induced by rainfall during Hurricane María in 2017, landslide runout length equations were developed for debris flows and debris slides in Lago Lucchetti and Loco. This poster assesses the accuracy of current landslide runout length models in the subtropical/tropical mountains of Puerto Rico and applies remote sensing data and GIS techniques to generate new landslide runout length equations. These equations estimate a total volume of mobilized sediment in the Lago Lucchetti Watershed and the extent of connectivity with fluvial networks.