Abstract
The accumulation of pollutants near the shoreline can result in low quality coastal water with negative effects on human health. To understand the role of mixing by tidal flows in coastal water quality, we study the nearshore Lagrangian circulation of four recreational beaches in Miami, FL, who, despite close proximity, have varying microbial levels. Specifically, we reveal Lagrangian Coherent Structures (LCSs), i.e., distinguished material curves which shape global mixing patterns and thus act as skeletons of the Lagrangian circulation. We show how these material curves, which shape circulation and mixing patterns, can be used to explain the incongruous states of the water at each that should comparable. We construct low-cost, satellite-tracked drifters for use in very shallow coastal areas and perform field experiments at each of the four beaches to validate the LCSs extracted from simulated currents.