Impacts of extreme hydrological events on Amazon floodplain hydrology and inundation dynamics

Prajjwal K Panday, Woods Hole Research Center, ppanday@whrc.org (Presenter)
Michael T Coe, Woods Hole Research Center, mtcoe@whrc.org
Paul Lefebvre, Woods Hole Research Center, paul@whrc.org
Marcia Macedo, Woods Hole Research Center, mmacedo@whrc.org
Leandro Castello, Virginia Polytechnic Institute and State University, leandro@vt.edu

Seasonally inundated floodplains and wetlands cover one fifth of the Amazon basin, promoting diverse biological communities and highly productive fisheries that sustain human populations in the region. Extreme droughts and floods trigger changes in the timing and extent of seasonal inundation, with potential feedbacks on the productivity of floodplain forests, macrophytes, and fisheries. The extreme droughts of 2005 and 2010, for example, caused river levels to drop to among the lowest recorded. This study examines the historical impacts of droughts and floods on the floodplain hydrology and inundation dynamics of the central Amazon, using coupled land surface and river/floodplain numerical models. We simulated historical river discharge and flooding in the central Amazon using the IBIS (Integrated Biosphere Simulator) and the THMB (Terrestrial Hydrology Model and Biogeochemistry) models, along with CRU (Climate Research Unit; CRU TS, v.3.21) climate data from 1940–2011. Observations at stations in the study area indicate that discharge is well-simulated for tributaries originating in Brazil, but is underestimated by more than 30% in basins originating in the non-Brazilian Amazon. Previous studies have suggested that this is driven by gross underestimation of precipitation in the Andes. To address this, we used the volume bias from the simulated and observed runoff to correct the input precipitation across the major tributaries draining the Andean Amazon (e.g. the Solimões, Japuŕa, Madeira, and Negro River Basins). We derived density weights based on elevation and annual precipitation using piecewise linear interpolation and applied it to distribute the volume bias across these four major tributaries. We present preliminary results from these analyses and validate simulated flood height and extent using existing satellite altimetry data and inundation maps derived from ALOS-PALSAR radar data.

Presentation Type:  Poster

Session:  Theme 4: Human influence on global ecosystems   (Mon 4:30 PM)

Associated Project(s): 

• Castello, Leandro: Impacts of floods and droughts on aquatic macrophytes, forests, and fisheries of central Amazonian river floodplains ...details

Poster Location ID: 87