Giosan, Liviu1, Cornel Olariu2, Janok Bhattacharya2,
(1) Woods Hole Oceanographic Institution, Woods Hole, MA
(2) University of Texas at Dallas, Richardson, TX
(3) University of Bucharest, Romania
ABSTRACT: Large Scale Coastal Behavior in Deltas: An Overview of the Danube Delta
Studies of large-scale morphodynamics are necessary in establishing the key controls on
deltaic development; they are also essential steps in refining numerical models that
address the 4D architecture of deltas. Although there has been much progress in
understanding sediment deposition from river plumes, it is also necessary to study the
interaction between the plume and the wave-driven, longshore sediment transport system.
Wave-current interactions lead to convergence and sediment deposition at the mouth and
feedbacks develop between the morphology initiated by river plume deposition and
subsequent modifications by waves (and vice versa).
Sediment derived from the river could also impose heterogeneity in the nearshore (e.g., forced accumulation of muds in an otherwise energetic environment), leading to a strong coupling between hydrodynamic and morphodynamic processes even in regions far from the river mouth.
The longshore drift is the main linkage between adjacent coastal compartments and transmits morphological signals along the coast; this is clearly seen in coastal reorientations, a phenomenon common in deltas. Besides instabilities at river mouths, large-scale shoreline features can also arise from instabilities inherent in the relationship between longshore sediment transport and local shoreline; they are particularly important where a reorientation modifies significantly the nearshore wave regime.
We will discuss the large-scale coastal behavior of the Danube delta; this leads to a series of clarifications on its evolution and to concepts applicable to other locales.
AAPG Search and Discovery Article #90026©2004 AAPG Annual Meeting, Dallas, Texas, April 18-21, 2004.