Working as a conservation scientist I care for cultural heritage. My “problem” is that I’m also interested in the history of decay, including catastrophic events; just these phenomena that turn old masonry to rubble. But I’ve never seen it “live” (few have!) or just after it happened. Hence, on my visits to the medieval castle ruins in Surselva (Graubünden, Switzerland), deep down there is a secret wish that I may watch them falling down, crumbling to pieces or being taken by avalanches! Yet boldly rejecting to fulfil my desires is, for example, Cartatscha by Trun; at the very edge of the abyss the small tower should have fallen years ago. But this stout ruin with the region’s finest masonry has decided to live on. For how long?
Surselva – or Vorderrheintal, the valley which hosts one of the two sources of the river Rhine – is a region densely packed with castle ruins, remains of the medieval expansion and feudal system. It is also a volatile alpine landscape with frequent avalanches, rockslides and landslides. It even has one of the largest rockslides ever recorded globally, the Flims rockslide. After the last Ice Age, during warmer climatic conditions around 8.000 BC (European Mesolithic), 10 cubic kilometres(!) of rock loosened, slid 2000 metres down and dammed the valley east of the modern town Ilanz. Several lakes formed, and as the dams broke, catastrophic flooding resulted. Since then the river Rhine has eroded its way through the rockslide debris and created the famous and impressive Ruinaulta (Rhine gorge).
Though not in this elevated class of catastrophes, the numerous avalanches, rock and landslides in historic times have put their mark on the landscape – and in the minds of the people. Examples from the last decades include the 1984 avalanche in Sumvitg (Somvix), which destroyed the medieval St. Benedict church, as well as the 2002 debris flow that shattered the village of Schlans. And in the villages of Trun and Zignau debris flows and avalanches are so frequent that large-scale protection measures have been necessary in order to save lives and infrastructure.
We don’t really know how many of the about 50 castle ruins in the region that have been destroyed by such forces of nature. But it probably cannot have been many, for most ruins stand high up on solid bedrock or at terraces. Thus, their ruined condition is mostly a result of their use as stone quarries after they were given up, fire, neglect and perhaps earthquake, as well combinations of poor building construction and rain, snow, ice and wind – in other words natural weathering.
In this context the Cartatscha ruin by Trun is special. The tower has probably been used as a stone quarry, but what remains is in almost perfect order, despite neglect, growth of vegetation and heavy weathering of mortar joints. It was simply built very well. The builders were certainly also selecting the place carefully, but they didn’t bother much about the ground conditions and refrained from proper foundations: The problem of the ruin is its location on top of a high, eroding end moraine at the mouth of the steep Punteglias valley, a side valley to Vorderrheintal. The moraine developed as the Punteglias glacier was much bigger than today. Over the millennia it has retreated some five-six kilometres up the valley.
The history of the now two storey tower is obscure. It was probably built in the 13th century, four storeys high and part of a larger structure that may have belonged to a ministerial or governor at the nearby Disentis abbey. Perhaps it was in one way or another connected to the significant medieval and later iron and copper mines in the Punteglias valley? (Though works here are first documented by written sources in the 15th century.)
Local, green Verrucano (metamorphic sandstone/conglomerate) and erratic blocks of Punteglias granite are the main building materials, roughly dressed to form longish, ashlar-like stone. The stones were put up in very regular courses, which is the primary reason why the tower has fared so well. Only two or three other medieval towers in the region display similar masonry (e.g. Surcasti).
When Erwin Poeschel, the father of medieval castle research in Graubünden, visited Cartatscha just before 1930, there was no sign of erosion of the moraine. But as Urs Clavadetscher and Werner Meyer wrote their new Graubünden castle book half a century later (1984), a small landslide on the west side of the ruin had taken place. As I first visited the ruin in 2005 I was horrified to see the eroding edge partially below the single foundation stone at the southwest corner. However, with the good building construction in mind, it seemed clear that larger parts of the ruin ought to be undermined before it would collapse entirely.
Over the last six years smaller and larger stones along the eroding edge have fallen and it is slowly coming closer to the entire west wall. Also a former protective measure, a sort of wall in the zone of erosion, has disappeared during the same time span. Apparently, there is nothing that will stop the slow erosion, but yet unclear whether a further, real landslide can take place during heavy rain or thawing in spring time.
Through the years of regular visits, my secret wishes of catastrophe and collapse have given way for a humble desire that the fine little tower may stand stout for another few centuries. Rather typical; the more one gets to know a special building or ruin, the stronger the wish for preservation! But is this possible in the case of Cartatscha?
As always, preservation will have to take place along the line between the values we attribute the monument and the available means, technical, economical and otherwise. Is it desirable with heavy-duty stabilisation using concrete and anything else available for modern man? Or should one go for an eco-friendly approach, trying to plant bushes and trees that eventually may develop roots strong enough to consolidate the moraine? Or should one just let nature have its way, hoping that erosion will not speed up?
In the latter case we may look forward to a spectacular collapse in a year or two – or perhaps in a century!
Links & literature
Earlier posts at this blog on ruins in Surselva:
- A Mauerzahn at Grünenfels castle ruin (CH): Surviving 2011?
- The Mauerzahn at Grünenfels castle ruin (CH) revisited after massive snowfall
Ruins and other monuments at Wikipedia:
The Flims rockslide and Rhine gorge:
- Erwin Poeschel: Das Burgenbuch von Graubünden, Zürich 1930
- Otto P. Clavadetscher & Werner Meyer: Das Burgenbuch von Graubünden, Zürich 1984
- Graubünden und Naturgefahren
- Nature catastrophes in Surselva/Graubünden
- Old mines in the Punteglias valley: Bergknappe Nr. 34
Location of Cartatscha: