Deltas contain complex self-organizing channel networks that nourish the surface with sediment and nutrients. Developing a quantitative understanding of how controlling physical mechanisms of delta formation relate to the channel networks they imprint on the landscape remains an open problem, hindering further progress on quantitative delta classification and understanding process from form. Here we isolate the effect of sediment composition on network structure by analyzing Delft3D river-dominated deltas within the recently introduced graph-theoretic framework for quantifying complexity of delta channel networks. We demonstrate that deltas with coarser incoming sediment tend to be more complex topologically (increased number of pathways) but simpler dynamically (reduced flux exchange between subnetworks) and that once a morphodynamic steady state is reached, complexity also achieves a steady state. By positioning simulated deltas on the so-called TopoDynamic complexity space and comparing with field deltas, we propose a quantitative framework for exploring complexity toward systematic inference and classification.
Bibliographical noteFunding Information:
Partial support by the FESD Delta Dynamics Collaboratory (NSF grant EAR-1135427) and the Water Sustainability and Climate Program (NSF grant EAR1209402) is gratefully acknowledged. This work is part of the International BF-DELTAS project on Catalyzing action towards sustainability of deltaic systems funded by the Belmont Forum (NSF grant EAR-1342944). It is also a tribute to the Sustainable Deltas 2015 (SD2015) Initiative endorsed by the International Council of Scientific Unions (ICSU), which aims to increase awareness of delta vulnerability worldwide and foster international collaboration, knowledge, and data exchange for actionable research toward delta sustainability. This research benefited from collaborations made possible by NSF grant EAR-1242458 under Science Across Virtual Institutes (SAVI): LIFE (Linked Institutions for Future Earth). A.T. acknowledges financial support from the National Center for Earth-surface Dynamics 2 (NSF grant EAR-1246761) postdoctoral fellowship.
- channel networks
- delta classification
- graph theory