The Mediterranean is a relatively small, semi-enclosed sea, and it therefore serves as the drainage basin for everything that takes place on the land mass that surrounds it, including pollutants. Five major rivers flow into the Mediterranean: the Rhône (France), the Po (Italy), the Ebro (Spain), the Aksu (Turkey) and the Nile (Egypt), as well as hundreds of smaller rivers. The Mediterranean region has a temperate climate, causing considerable evaporation. The water that evaporates is replaced by water flowing in, mainly from the Atlantic Ocean, and the rate of water replacement – in other words, the time taken for all the water in the sea to be replaced – is around 80 years.
Some 150 million people live along the approximately 46,000 kilometers of Mediterranean coastline today, and during the summer months this figure is doubled by the influx of another 150 million tourists. This causes a heavy environmental burden on the coastal region.
The area of the Mediterranean Sea is only about 3% of all the seas and oceans which together cover 71% of the earth's surface. However, it carries around 30% of all global marine traffic and transport, which adds to the high pollution load.
All these factors, together with the increasing pace of development, urbanization and industrialization along the Mediterranean coast, are cause for concern.
Unlike the Mediterranean Sea by most of the countries along its northern coast, the sea off Israel's shores is not clear, deep and calm but instead is of moderate depth, and is characterized by a very stormy system and considerable mixing of sand and sea, sometimes creating a certain turgidity of the water.