The Su Gologone spring’s highs and lows
The Su Gologone spring is a place where we often stop with groups and also privately, it’s an excellent quick stop to score some valuable points, and besides that a good spot for a coffee and a toilet break when you’re on the road.
Sometimes they organise events, life music, open air yoga sessions etc.
However when it rains heavily hell breaks loose!
What happens is that the river brings down water to the lake, the spring and the Sa Oche cave too, and the level of the lake can even rise a few dozen meters further down stream. In that case the whole area around the spring floods, and can rise by even more than 10 meters.
Fortunately the water doesn’t come down with a lot of violence, but still, it’s strong enough to lift up and move the terrace covering of the kiosk for example as happened in 2013 and leaves a big mess in general. After the dam is opened up the water level slowly comes down again and mud and branches are left everywhere and the guys running the bar and guide service have to clean for days and put a lot of effort into getting ready again for the season.
Here is how it all works:
Su Gologone is a very impressive fresh water spring, where hundreds of liters of water per second come to the surface. The proven depth is 135 meters, which makes it one of the deepest pot holes filled with water in Europe. Basically the spring is the exit of a karst system, more than 3o km long and with a capacity that’s bigger than the lake it borders on. Exit, because the surrounding mountains where it gets it’s water from, and the cave system underneath them are all higher than the spring, which lies at only just over 100 meters above sea level.
– karst actually means limestone, the Karst mountains are situated on the border between Slovenia and Italy, they are composed of limestone, and this was the first area where research was carried out on limestone erosion and the topography caused by it. Hence karst became synonimous for limestone and therefore it’s also used here in the Supramonte mountains.
Parts of this intricate karst – cave – system hav been explored, by the various local caving clubs, however big parts of these caves are at least partially filled with water, and that’s where the cave divers come into play. Different hazardous expeditions have been carried out throughout the years, and the italian cave diver Alberto Cavedon ( is his name a coincidence or what?) reached the incredible depth of 135 m in 2010.
What comes after these 135 meters of depth is still a mistery, but due to tests with coloured water it is known that the springs are connected with several other caves in the Supramonte area which are up to even 20 km away in a straight line.
Therefore it is known that the surface area from which it gathers its water is around the 180 square kilometers big. So when it starts raining heavily hell breaks loose! From the surface the rain water sipples and runs down into the underground cave systems which are literally more than 30 km long and a lot of this water than ends up running out of the spring of Su Gologone. Not all of it though, some fills up the underground lakes so that also when it’s not raining the spring is active, and then a big part of the excess water runs out of the Sa Oche cave in the Lanaitto valley, about 5 km away.
Both the excess water from the spring and from the Sa Oche cave bring their water to the artificial Cedrino lake, that extends for some 7 km. The Cedrino lake springs in the Supramonte of Orgosolo at around 1200 m. a.s.l., and also big a big part of the rain water fills the river before it reaches the spring.
All in all this can cause the Cedrino lake to fill up even overnight! So in the time of year when the heavy rains can be expected the water company Abbanoa (litt. new water) has to make sure that the lake is empty. If not they have to open the dam, which causes problems in the towns further downstream. The risk in Galtelli and Orosei is that they get their feet wet and their basements full of water! And of course this has happened a few times in the last 15 years.
Which is one of the reasons that the dam in the Cedrino river was built (in the seventies) in the first place, so not just as a water reservoir, but also as a protection against flooding.