Influence of Magnitude and Period of Sea-Level Cycles on Flow Confinement in Delta Distributary Channels

Deltas sit at the interface between land and sea, and therefore display some of the earliest responses to rising global sea level and environmental change. One of the ways that deltas react to changes in the environment is through adjustments in the geometries and behaviours of their distributary channel networks. This response of delta distributary channels can be reflected in changes to channel mobility, channel geometry, and the ways in which water is routed through channels and across floodplains.

This study uses a previously published dataset from a physical delta experiment conducted in 2015 in the Tulane Delta Basin (TDB-15) to examine the effects of sea-level rise on the degree of flow channelization across the delta surface. A moderately cohesive sediment mixture was used in the experiment, and relative sea-level cycles were imposed on two-time scales: the first scenario was low magnitude, long period cycles, and the second was high magnitude, short period. The data consist of overhead images taken every 15 minutes, which are used to quantify changes in flow channelization by classifying image pixels into three categories: dry, channelized flow, and sheet (unchannelized) flow. These measurements allow us to analyze the effect of rising sea-level on delta distributary channel networks to better understand the behaviour of natural systems.