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Israeli Mediterranean river mouths are characterized by an extremely dynamic morphology, as their channels tend to migrate hundreds of meters north and south along the shoreline. This study aims to characterize the impact of the topographic setting of the beach on the dynamic morphology of seven of these river mouths. This was achieved by morphologically mapping and monitoring the natural channel dynamics of each mouth over time; recognizing their spatial and temporal migration and avulsion patterns; describing, generalizing and classifying the different types of river mouths present on the coast; and investigating the influence of the adjacent topography on their morphology. Detailed geomorphologic mapping was achieved using remote sensing and GIS techniques, utilizing more than 300 aerial photographs taken between 1918 and 2005. This study revealed a number of typical differences in these patterns, attributed to differences in the topographic setting of the beach in the vicinity of the mouths. “Elongated strip” topography coasts demonstrate a uniform slope beach with equally spaced elevation contours, forming a narrow sandy strip between the shoreline and the back-berm. “Funnel” topography coasts exhibit a non-uniform slope with a funnel-shaped topographic depression adjacent to the river mouth. Similarities were found between the spatial and the temporal morphological patterns of river mouths flowing in each of these two topographical settings. Elongated strip mouths are deflected alongshore a barrier and demonstrate high migration distances and little temporal change. The morphology of funnel mouths was found to be highly temporally variable yet less spatially dynamic, as these mouths' channels are restricted by their funnel topography. This study concludes that the topographic setting of the beach, a constant element in the temporal scale of this study, is a primary factor influencing the morphology of the studied mouths. |
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