The Canal de Castilla

 This remarkable canal is one of the most important examples of 18th/19th century engineering in the whole of Spain and yet it never reached its planned terminus at the Bay of Biscay. Three factors overcame the project. One was the problem of crossing the Cantabrian Mountains (which should really have been predictable) and the second was the delays and budget constraints caused by the Peninsula Wars (Spanish War of Independence) in the early 18th Century. These delays eventually led to the final problem, which was the technical development of the railways, which, with the full cooperation of the canal company, arrived at the northern terminus of the canal in the late 1850s.  Overall it took about 100 years from the start to the decision to end further northward progress at Alar del Rey, but in that time over 400 km were built. Two branches originating close to the middle of Spain at Valladolid and in Medina de Rioseco join just north of Palencia and then terminate at Alar del Rey in the north. 

The locks are of a very unusual shape and some of them were filled by cascading water over small weirs directly down the curved masonry walls. The iconic bulbous shape of the lock chambers allowed 2 boats into the lock at a time and a stylised image of a multi-basin lock (probably the famous one at Frómista) is currently used as the symbol of the canal on road signs etc. The canal has important features such as aqueducts and lots of flood control gates with 18th century architecture, but often with 20th century metal gates. There is also an interesting system where the river level is raised by a weir to canal level so as to permit boats to cross the river without needing either an aqueduct or a lock system. This is at Herrera de Pisguera, which is the site of both an interpretation centre and a mooring for a trip boat.

The canal can be followed on foot or by bike or you can skip from point to point by car. The irrigation process has generated a number of wetlands which are protected because of their ornithological importance, particularly for the aquatic warbler and the bittern.

The canal was originally planned by the Marques de la Ensenada during the early 18th century. At that time a large excess of grain was being produced in the area of central Spain known as the Gothic Plain (also known as the Tierra de Campos). The canal was also meant to facilitate the inflow of products from the Spanish colonies into the centre of the country.

During the peak period of activity (1850-1870) up to 400 vessels operated on the canal. The barges were normally pulled by mules but some early photographs show these barges being pulled by hand across the Pisguera weir, with a mule team tethered to the deck of the boat. In the early 20th century the barges were also known to have been towed by powered tugs and later were self-powered.

When the decision was made to promote rail rather than canal to the north of Alar del Rey, and onwards to the coast, the subsequent further development of railways in central Spain led to a decline in investment and repairs on the canal and this was compounded by the fact that the canal company only had control of the waterway until the end of its concession agreement with the Crown. The canal was eventually handed to state control when the concession ended in 1919.

In the 1950s most of the locks were converted to cascades to allow the canal to continue to be used for irrigation and water supply (but with much reduced maintenance), an important function which continues to the present day. There have been recent efforts to utilise the tourist and historical value of the canal. Three trip boats operate on various sections, interpretation centres have been established and signs indicating appropriate motorway junctions have been established. Parts of the canal route have been linked to the various pilgrim routes to Santiago de Compostela.