We are lucky to live on the Gulf of Trieste, it is always spectacular. Some days it is flat and slick like a mirror without even a ripple. Other times it is churning with cresting white caps thanks to the bluster of the Bora. Sometimes it is a myriad of baby pinks and blues at sunrise, fiery orange as it reflects the incredible Triestine sunsets and black as pitch at night while the full moon dives below its surface.
And then there are those rare times, usually after a big rain storm, that you look out and see something quite unusual; the convergence. One part of the gulf is its usual azure while another part is almost a milky blue with a very clear line of demarcation separating the two. What creates this weird effect you ask? The Isonzo river overflowing into the gulf.
The Isonzo (Soča in Slovene; Isonzo in Italian; Lusinç in Friulian) is a 137 km long river that originates in the Alpine area of western Slovenia. From the Karst springs located in the Zadnja Trenta at 1050 meters above sea level, the river flows through Slovenia through the glacial valley of Trenta and the Bovec basin, passes through Kobarid, Tolmin and Kanal ob Soči up to Solkan. After 96 kilometers it crosses the border and flows through the cities of Gorizia, Gradisca, Villesse and Turriaco where it empties out into the gulf of Trieste on the Adriatic Sea.
Since ancient times the Isonzo, whose name derives from the Celtic “Eson”, was the site of many conflicts given it’s strategic location. In the surroundings of the river, it is common to find ruins of ancient castellieri (fortifications), as well as signs of the many previous populations that inhabited the territory, from the Romans, to the Lombards and the Byzantines, medieval strongholds and Venetian and Austrian fortresses. Although the river perhaps is best remembered for the twelve battles of Isonzo during WW1 between May 1915 and November 1917, in which over 300,000 Austro-Hungarian and Italian soldiers lost their lives.
Despite this brutal past, the river’s beauty is indisputable. It has an incredible greenish hue that it maintains along its entire course and which does not ever completely fade. The river is in fact known as ‘the emerald beauty’. It owes this incredible color to small particles of bedrock suspended in the water, silt composed of limestone and marl deposits typical of the region.
It is this silty river water that spills out into the Gulf after a rainstorm that creates the convergence of the sweet river waters into the salty waters of the sea resulting in this startling effect.