Impact of Discharge Variability on Sedimentary Characteristics in Shallow-Water Deltas

Discharge variability significantly impacts the sedimentary characteristics and growth processes of river-dominated shallow-water deltas. In this study it aims to explore the macroscopic morphology and internal architecture of deltas under different discharge variability conditions. Based on modern sedimentological and hydrological data, numerical simulations of deltaic sedimentation under varying discharge conditions were conducted using a hydrodynamic modeling software. The findings indicate that flow variation controls channel migration rates and avulsion frequencies, thereby influencing the geomorphic and architectural features of deltas. Under high flow variation conditions, deltas exhibit fan-shaped geometries, frequent avulsion, bifurcation, and abandonment of distributary channels, resulting in complex channel networks. Channel numbers increase significantly, sedimentary material expands laterally, delta areas grow larger, and shorelines become smoother. In contrast, under low flow variation conditions, deltas are primarily bird-foot shaped, with fewer and more stable distributary channels. Sediments concentrate at the river mouth, and shoreline roughness is higher. These findings provide a scientific basis for analyzing similar deltaic sedimentary patterns and predicting hydrocarbon reservoir architectures.