Anthropogenic Modifications of Global River Delta Plains and their impact on Riverine Sediment Fluxes

Abstract:

River deltas are among the highest populated areas on the planet. Valuable natural resources, fertile grounds, and convenient locations for trade have proven deltaic land to become hot spots for urbanization, industrialization, and food production over the last few decades. Human settlements, consequently, have modified deltaic land through agriculture, construction activities, sand mining, and aquaculture, and thus have significantly altered the sediment flux contributions to the river channel network within the delta plain.

This study’s main goal was to understand the contributions of sediment fluxes to the channel network explicitly from within the delta plain. We use recently released global datasets; two vectorized datasets with attributes on global scale river reaches and their hydraulic parameters, and three raster products on human modification to global land surfaces, on 45 large river deltas, in addressing the research goal.

Results of the study provide (a) quantitative understandings of sediment flux loadings to the channel network from delta plains including exploratory relationships of fluxes between different channel orders, (b) the degree to which humans have modified delta plains from their pristine conditions, and what the governing factors (e.g. agriculture, transportation, energy, settlements) of these modifications are, and (c) quantitative understandings of how these different governing factors of human influence control sediment fluxes in the channel network within the delta plain.

The outcomes of this study yield several novel insights into delta plain channel fluxes of the 21^st century, and not only transforms our analytical capabilities for studying human influences on river deltas, globally, but also provide a platform to better estimating fluxes at the feeder river outfall(s), large scale flux modeling endeavors, erosion/accretion in different parts of the deltaic land-sea interface, and zonal planning operations for long-term sustainability of deltas.