I have a mild obsession with endorheic basins, those magical places where where water flows into them and never flows out except through evaporation. They’ve appeared several times on the pages of Twelve Mile Circle over the years. I’ve even discussed an example in Europe before, Lake Neusiedl on the border between Austria and Hungary. There were a few more of those special spots in Europe with similar properties so I decided to take a moment to explore them vicariously. None of them were particularly large although they fascinated me nonetheless since Europe wasn’t generally known for having endorheic basins. Each of them also seemed to be noteworthy in a way completely distinct from their unusual lack of drainage.
Lake Trasimeno, Italy
isola maggiore by Olga e Zanni via Flickr (cc)
Italy’s Lake Trasimeno (Lago Trasimeno) was the largest of the latest set I examined, with a surface area of 128 square kilometres (49.4 square miles). That made it big enough to be Italy’s fourth largest lake. It formed in the region of Umbria, about as far as one could get from a coastline in the middle of the long Italian leg. The lake had been part of a shallow sea three million years ago, created in a depression formed by fractures in the underlying stone. It retained that shallow shape in modern times with an average depth of only about five metres. However, Lake Trasimeno varied greatly in size and depth based on cycles of rainfall and evaporation, expanding and retracting dramatically at times.
To me, the most fascinating aspect wasn’t so much the lake as the three islands set upon the lake. Medieval inhabitants used this topography to create protected spaces with a picturesque, natural moat. One of the islands, Isola Maggiore (map), included a village with a large Franciscan monastery. It was noted by many sources that St. Francis of Assisi lived as a hermit on Isola Maggiore for 40 days during Lent, possibly in the year 1211, when it was uninhabited. A few people still live on the island today, albeit with regular ferry service and a steady stream of tourists connecting it to the outside world.
Lake of Banyoles, Spain
Another endorheic basin developed in Catalonia, Spain. Lake of Banyoles (Estany de Banyoles) formed next to a geological fault line (map). The Catalan version of Wikipedia had a rather detailed explanation. It was essentially sandwiched between an area of porous karst limestone on one side and a layer of waterproof stone on the other that blocked any outward flow. Unlike Lake Trasimeno, the primary source of water for Lake of Banyoles could be traced to the local aquifer. Water flowed easily into the lake through porous karst, thus replenishing water lost through evaporation in a reliable manner, and keeping lake levels relatively stable. Man-made canals were added to drain swampy areas and create a spillway for times of particularly heavy rainfall. Technically, I supposed, that converted Lake of Banyoles into something not quite completely endorheic since it drained to the nearby Terri River at times. I still kept it on the list.
Even though it was the largest lake in Catalonia, Lake of Banyoles was still pretty small and covered an area of only about 1.12 km2 (0.43 sq mi). Nonetheless it formed in a long, skinny manner making it absolutely perfect for the sport of rowing. Many rowing championships have been held on the placid waters of Lake of Banyoles in recent decades including all fourteen of the rowing events for the 1992 summer Olympics based in Barcelona. The video, for example, showed the medal round held on the lake for the Men’s Coxless Pair competition. Great Britain won the gold medal. My juvenile sense of humor found the phrase "Men’s Coxless Pair" to be slightly amusing. I should probably move on to the next section before it crosses over a line into something distasteful.
Lasithi Plateau, Greece
view from Zeus's Cave, Lassithi Plateau, Crete, October 2012 by alljengi on Flickr (cc)
The final spot I examined didn’t include a catchment area large enough to produce a lake. Nonetheless the Lasithi Plateau on the Greek island of Crete was a fertile valley with a long history of settlement, with sufficient rainfall and snow melt to support a steady population. I found it particularly fascinating that an endorheic basin emerged on an island, and yet there it was covering a good 18 km2 (48 sq mi), hemmed in on all sides by mountains.
The adjacent mountain caves actually attracted my attention more than the plateau itself. One in particular near the village of Psychro was called Diktaion Andron, or Diktaean or Dikteon or other variations (map). Its spectacular formations were known to Neolithic people and later it became a sacred place of worship and sanctuary during the Minoan period. Greek mythology held that the god Zeus was born in this cave. That gave a pretty good indication of the prominence Diktaion Andron held for the people of that time. It pleased me that Zeus would have been born next to a geo-oddity.