I have a mild obsession with endorheic basins. Those are magical places 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.
A few more of those special spots with similar properties exist in Europe. So I decided to take a moment to explore them vicariously. None of them covered a large area. However, they fascinated me nonetheless because of their rarity here. Each of them also seemed to be noteworthy in a way completely distinct from their unusual lack of drainage.
Lake Trasimeno, Italy
Italy’s Lake Trasimeno (Lago Trasimeno) covered the greatest territory of the current set. It stretched across a surface area of 128 square kilometres (49.4 square miles). That made it big enough to be Italy’s fourth largest lake. This one sat 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. It formed in a depression formed by fractures in the underlying stone. Likewise, it retained that same 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. Many sources noted 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 appeared in Catalonia, Spain. Lake of Banyoles (Estany de Banyoles) formed next to a geological fault line (map). The Catalan version of Wikipedia provided a rather detailed explanation. It fell within 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, a local aquifer became the primary source of water for Lake of Banyoles . 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.
Later, people added canals 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. Nonetheless, 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). But it formed in a long, skinny manner making it absolutely perfect for the sport of rowing. Many rowing championships take place on the placid waters of Lake of Banyoles. This included all fourteen of the rowing events for the 1992 summer Olympics based in Barcelona. One event involved the Men’s Coxless Pair competition where 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
The final spot I examined didn’t include a catchment area large enough to produce a lake. Even so, 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. Local residents called one particular cave near the village of Psychro something like Diktaion Andron, or Diktaean or Dikteon or other variations (map).
Neolithic people knew about these spectacular formations. 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.
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