A canal is an artificial waterway, typically one built for transport, although they can also merge with aqueducts when used for water supply or drainage (or sewerage). Some canals have also served to supply hydraulic power, either to water mills or hydroelectric schemes. In a few cases a canal could also be dug as a defensive measure - serving, in effect, as an enormous moat.
Canal building was historically limited to the connection of bodies of water at the same approximate altitude until the invention of the lock gate. This technology cropped up from time to time across the world, but seems to have become mainstream in Europe during the 17th century, serving to provide transport and power for the Industrial Revolution.
Most canals use small boats, often of a specialised design with a narrow beam (to allow for the narrow width of the channel) and a length limit dependant on the size of the lock gates. By contrast, a few canals - such as the Panama, Kiel or Suez are designed to allow passage for sea going ships and, although they also have limits to beam, length and draught, have far more room.
Canals excelled in the transport of heavy or fragile goods in eras where road transport was unreliable, and continued to ship fragile goods (from pottery to explosives) long into the era of the railways - although in a few cases canals were drained and their beds used as railway cuttings. In the modern era they are mainly used for leisure travel and large areas of many nations canal networks are at least semi-derelict, although in many cases regeneration work has been started, sometimes coupled with attempts to revive commerical freight.
In many cases, especially in urban areas, canal restoration has lead to these waterways being transformed from rather grim and utilitarian structures to prestigious "waterfront" and playing a key role in urban retail and leisure. This is often an important part of urban redevelopment as formerly industrial cities are forced to change role and many such places have a surprising amount of canal frontage.
Game and Story Use
- The digging of canal navigations should be a key sign of impending industrialisation at most pre-modern scales.
- A shipping canal might well serve an important strategic role in a campaign.
- A big enough castle building project (or any other big construction) might warrant a canal to haul the stone and other stores. Once complete it can be integrated into the defences and help to keep the castle supplied (and probably take away it's sewage). With a little thought the engineer may even be able to turn a swamp into usable land along the way.
- Note the engineering requirement - only the very simplest canals are nothing but a big ditch … if it needs locks and other complications it becomes a relatively sophisiticated hydraulic engineering job.
- A new canal could have significant economic benefits for the communities it serves, but could also lead to conflict with established transport industries and other vested intrests.
- Basically it allows you to play a Western style railroad plot back into (at least) the medieval era.