Lake Velino

The Rieti Valley or Rieti Plain (Italian: Piana Reatina or Conca Reatina) is a small plain in central Italy, where it lies the city of Rieti, Lazio. It is also known as Sacred Valley and Holy Valley (Italian: Valle Santa) since saint Francis of Assisi lived here for many years and erected four shrines, which have become the destination of pilgrims.

It is the center of the Sabine region and an important part of the province of Rieti. Originated from the draining of the ancient Lake Velino, it is crossed by the Velino river and bordered by Monti Reatini and Sabine Mountains.

In prehistory the Rieti Valley was enterely occupied by a large lake which ancient romans called Lake Velinus, since its tributary was the Velino river. The lake was formed during the quaternary, when limestone carried by water in the river deposited in the tight canyon where it flowed, shortly before joining the Nera river, near the present-day village of Marmore. As a result the riverbed was occluded and the Rieti Plain was flooded becoming a lake. The water level in the lake raised and lowered several times during the centuries, favouring the formation of wide marshy zones around the lake where it was insalubrious to live because of malaria.

For this reason in 271 BC (after that ancient romans defeated the Sabines and acquired control of the area), consul Manius Curius Dentatus decided to drain the lake by digging an artificial canal in the limestone rock at Marmore. This imposing engineering achievement created Cascata delle Marmore, a 165 m (541 feet) tall waterfall by means of which the Velino river could flow again into the Nera river, and allowed the large and fertile valley to be farmed. Of the original, great lake only some minor lakes remained, the largest being Lago di Piediluco.

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Wikipedia