Sediment transport dynamics in a glacierized Andean basin: lessons from the Estero Morales, Chile

Abstract

Suspended and bedload transport dynamics on rivers draining glacierized basins depend on complex processes of runoff generation along with the degree of sediment connectivity and coupling at the basin scale. This thesis presents a recent dataset of sediment transport in the Estero Morales, a 27 km2 glacier-fed basin in Chile where suspended sediment concentration (SSC) and bedload (BL) fluxes have been continued monitored during two ablation seasons. The relationship between discharge and SSC depends on the origin of runoff, being transported in higher quantities during glacier melting, although the hysteresis index reveals that sediment sources are closer to the outlet during snowmelt. As for suspended sediment transport, bedload yield and availability depend on the origin of runoff. The relationship between discharge and BL reveals that early glacier melt period transport higher quantities of coarse sediments, and with higher efficiency, and the hysteresis suggests that sediments are provided by the proglacial area. Differences in volumes of transported sediments between the two studied ablation periods reveal differences in coupling mechanism on the sediment cascade, due to progressive changes of type and location of the main sources of runoff and sediments in this glacierized basin.