Lock 1

Lock 1, built between 1759 and 1804, is the first lock on the North Branch and a prime example of the hydraulic engineering of the Canal de Castilla. Its oval basin, nearly 30 meters long and over 9 meters wide, is constructed of sandstone and retains the original supports where the winches that operated the gates were mounted. The structure includes a fixed-lip spillway that diverts part of the flow into an open channel—a unique feature on this branch—before reintroducing it downstream. Its state of preservation is good, although the surrounding area is in fair condition. Located 2.4 km from the canal’s source, the lock maintains a direct connection with the agricultural landscape and the nearby village of San Quirce del Río Pisuerga, reinforcing its territorial and heritage value as a key component of the navigation system.

Several secondary elements are arranged around the main structure, completing its functional interpretation. The bridge over the lock, built of sandstone ashlar with a semicircular arch, allowed passage between banks and ensured the continuity of the road. Its condition is good, although it has lost its original parapets, which are planned to be replaced using traditional materials. The bridge at the diversion, also made of sandstone and considered to be two bridges joined together, spanned the secondary canal that accompanies the lock and is in fair condition. The old hydroelectric power station, formerly a mill, retains its rectangular layout, wooden structure, and masonry and brick walls; although part of it is in ruins, it maintains internal mechanisms and considerable architectural value. Finally, the Conejera culvert, built of sandstone ashlar and in good condition, allows the canal to cross over the stream, completing the complex as essential infrastructure.