Cumulative Effects of Climate Change and Anthropogenic Activities on Madeira Watershed Hydrosedimentology

Código

PAP084

Autores

Trey Crouch, DAVID KAPLAN

Tema

MUDANÇAS CLIMÁTICAS E PROCESSOS HIDROSSEDIMENTOLÓGICOS CONTINENTAIS E COSTEIROS

Resumo

Like much of the Amazon basin, the Madeira River watershed is in a state of transition, driven by land-use/land-coverchange (LULCC), hydropower development, and a changing climate. In this study, we present a non-parametric framework to quantifythe sensitivity(or elasticity) of Madeira River flow (Q) and sediment load (Qs) to projected changes in climate (potential evapotranspiration and rainfall) and proposed development. An empirical model from the literature was used to predict present-day,long-term sediment loads. This simple model, referred to as ?BQART?, is the basis for the distributed rainfall-runoff, sediment load estimationsto be used inthe elasticity analysis. Preliminary results show that the empirical model performed fairly well, overpredicting long-termsediment load for the Porto Velho monitoring station by 8% and under-predicting sediment load by 14% at the Rurrenabaque station.Deviations between observed and estimatedQsmay be due to underestimating human impacts(e.g., deforestation and land clearing for agriculture) and sediment trapping. These preliminaryresults show promise for continuation of the proposed modeling framework, which consists of comparing BQART model results for present-day conditions with alternative scenarios that include projected climate and development as separate inputs.We hypothesize that the sediment trapped by planned dams will exceed that of the climatechangeand LULCC-induced increases in sediment load.Resulting sediment trapping is expected to significantly change suspended sediment concentrations andgrain size distributions. The proposed modelwill also provide a platform for testing hypotheses aboutchanges to dominate sediment production processes and optimal dam scenarios.Major assumptions and shortcomings of the model and elasticity analysis are discussed throughout.