The heritage complex of Lock 3 of Campos was built between 1842 and 1849 and is located on the Campos Branch of the Canal de Castilla, in the municipality of Castil de Vela (Palencia), at kilometer 137.070. This site is part of the mature phase of the canal, when hydraulic engineering reached a high degree of precision to regulate the differences in levels, control the flows and ensure both navigation and maintenance of the infrastructure in an essentially agricultural territory.
The main feature is Lock 3 itself, a simple, rectangular lock with approximate dimensions of 27.60 meters long, 5.10 meters wide, and 4 meters high. It is constructed of limestone masonry and retains the original supports for the operating winches, which reinforces its historical value. On the right bank, upstream of the lock, there is a lateral spillway that extends above ground before flowing into a buried conduit that empties directly into the lock basin. The drainage from the same bank also flows into this conduit. This arrangement allows for effective control of the water level and protects the stability of the structure.
Associated with the lock is the bridge that crosses it and also spans the diversion channel, likewise built between 1842 and 1849 of limestone ashlar. It features segmental arches, with two main arches—one over the lock and the other over the diversion channel—and a smaller arch on the right bank. The base of the pier extends downstream in a rounded shape that regulates the confluence of the water flows. The bridge retains its complete parapets and wing walls and is in a good state of preservation.
A visit to the Campos Lock 3 complex allows visitors to understand the Canal de Castilla as a perfectly articulated technical and territorial system, where water, roads and landscape are naturally integrated.
