Shoreline sensitivity to oil spills, the Mediterranean coast of Israel: Assessment and analysis
Abstract This study, which was carried out during 1999–2002, deals with the identification of the environmental sensitivity of the Mediterranean coastline of Israel to marine oil spills. It includes GIS sensitivity mapping and an analysis of the environmental vulnerability of Israel's shoreline resources. The study analyses the main sources of risk for maritime accidents in the southeastern Mediterranean and develops scenarios for possible oil spills incidents, including an analysis of the priorities for protection of the various coastal ecosystems, in an event of a large spill. It describes the morphology of the coastline of Israel, as well as the main hydrographic and meteorological patterns that dominate and control the dynamics of the shorelines, and of potential major oil spills. The study also discusses the different ways in which oil spills may affect natural ecosystems and socio-economic resources along the coastline of Israel. The basic research question of the study was how different geomorphic and land-use types of the Mediterranean shoreline would be affected by large quantities of spilled oil washing ashore from the sea. The study aims at determining the relative sensitivity of different types of shoreline and ‘prioritizing’ the different types of shoreline and coastal resources to be protected following a large oil spill. The study also aims at presenting the data collected and analyzed to both the scientific and environmental communities, and to the operational national authorities responsible for oil spill preparedness and response, in a clear and useful way. One of the main conclusions of the study is that generally, the sensitivity of the Israeli Mediterranean coastline to oil spills could be considered moderate, compared with other fragile ecosystems. This is mainly because of the morphology of the sandy beaches and the high exposure of most types of beaches to energetic natural cleanup processes. Still, along the southeastern Mediterranean coastline there are ecosystems, habitats, shoreline types and coastal resources that are sensitive to oil spills.
Dynamics and management of sand along the Israeli coastline
L'augmentation considerable de la densite de population dans la plaine cotiere d'Israel depuis le debut du siecle a modifie les processus naturels, entrainant un deficit en sable de cette cote. On estime a quelque 20 millions de m 3 le sable disparu du systeme cotier en raison de l'extraction sur les plages et des retenues provoquees par les structures immergees. On possede deja des indications sur le degre d'erosion cotiere qui resulte de ce deficit. Le volume de sable naturellement depose par le transport littoral de sediment est estime a 170 000-540 000 m 3 par an; cet apport ne suffira pas a reparer les dommages deja occasionnes et encore moins a repondre a la demande entrainee par le developpement important des infrastructures sur le littoral israelien, prevu pour les deux prochaines decennies. Deux sources d'approvisionnement en sable pourraient etre explorees: un gisement eventuel sous une couche de boue au centre et aux marges du plateau continental ainsi que des importations en provenance des vastes dunes du nord du Sinai, en Egypte.
LONGSHORE TRANSPORT PREDICTION - SPM 1973 EQUATION
The 1973 Shore Protection Manual (SPM) predicts longshore transport rates that are 83% higher than its 1966 predecessor, for the same wave conditions. This upward revision is the result of concurrent increases due to (1) deletion of all laboratory data used to establish the 1966 prediction, (2) addition of Komar's (1969) field observations, and (3) limiting energy flux values computed from previously unused data obtained at Santa Barbara (Johnson, 1952). A derivation based on conservation of energy shows that P. is the longshore component of the energy flux confined between two wave orthogonals spaced a unit distance apart in the longshore direction, and that a term previously identified as the onshore component of energy flux is identical with the total energy flux in the direction of wave travel between these orthogonals. Use of submerged weight transport rates has no engineering benefit at the present time because: (1) all available data are in terms of volume rates, (2) conversion to submerged weight requires estimates of the void ratio and sand grain density which have been assumed constant in practice, and (3) the engineering problem needs volume rates which would require reconversion back to volume rates if an immersed weight prediction were established.