From the earliest dawn of history man has used rivers and lakes as a means of transport and it was inevitable that he would gradually develop engineering techniques to make natural rivers more useful to him. First came the weir, a wall built across the river which held water in the stretch above at a constant level and allowed the surplus water to flow over the top. These early weirs had a threefold purpose: fishing, diverting water into millraces to develop power and improving navigation by raising the level of water over shallows. Some means, however, still had to be found to pass boats through the weirs from one level to the next. Over 2,000 years ago the Chinese invented vertically rising gates through which boats could be hauled upstream or lowered downstream. This was found to be very wasteful of water and so the early Chinese engineers experimented with slipways, which were built into the weirs, but it was very cumbersome hauling boats up and down these slopes and caused damage to the hulls. Eventually, in AD 983, the pound lock was invented, a chamber built into the weir wall with vertically rising upper and lower gates, into which boats could be floated and raised or lowered; the inventor was said to be Chhiao Wei-yo, assistant commissioner on the Grand Canal of China.

The first pound lock in Europe was built on a river in Holland in 1373 but it was left to that greatest of all inventors, Leonardo da Vinci, to invent the swinging or mitre gates which we still use today; apart from mechanising the operation no one has managed to improve on his design since then. At first, short lengths of canal were used to by-pass shallow stretches or places where there were sharp bends in the river, but it was not long before engineers became more ambitious and constructed canals which climbed up to a summit level and dropped down again, making it possible to link watersheds. The remarkable Canal du Midi, built in France between 1666-81 and still in use today, is a fine example of an early still water canal. It established a link between the Atlantic Ocean and the Mediterranean Sea, rising up from Sète on the shores of the Mediterranean to a summit level and dropping down into the River Garonne near Toulouse.

In Ireland, as elsewhere, much use was made of the abundance of slow flowing rivers and large lakes in a countryside which was heavily forested with few roads. Unfortunately, these water highways also gave unwelcome visitors easy access into the interior of the country. The pages of the Irish annalists are full of records of Viking incursions; there are few more terrible stories than the voyages of terror made by the Dane, Turgesius, in the mid-ninth century up the River Shannon to Lough Ree and up the Bann into Lough Neagh. He plundered and desecrated monastic settlements as he went, declaring himself to be the Abbot of Armagh while his wife, Oda, gave oracles from the violated altar of Clonmacnoise. Maelshechlainn, King of Meath, succeeded in capturing him by a clever ruse. Turgesius coveted the king's daughter and he sent her to him accompanied by fourteen 'maidens' - warriors in disguise - who took the Dane and his followers by sur prise. Turgesius was captured and drowned in Lough Owel, ending his reign of terror. In the following century there were further incursions from Scandinavia. In 968 Brian Boru raised a fleet and inflicted defeat on the invaders in Lough Ree but twenty years later he found himself siding with them when his former allies from Connacht deserted him and joined forces with Maelshechlainn II against him. Brian assembled a fleet of 300 ships to do battle with him on Lough Ree but eventually reason prevailed and the two Irish leaders met at the mouth of the River Inny where they agreed to divide the country between them.

There is evidence that weirs were constructed on many Irish rivers, and in the twelfth century an artificial channel was cut through an island at the south end of Lough Corrib which is still used today. It was not, however, until the first half of the seventeenth century that a definite scheme for the development of Irish waterways was put forward when Strafford, the Lord Deputy, suggested linking the major rivers. After the Restoration in 1664, the Duke of Ormonde in his well known instructions included 'making rivers navigable', but it was not until the early eighteenth century that more serious attempts were made to carry out proper surveys and lodge plans before the Irish parliament. Eventually, in 1715, an Act was passed 'To Encourage the Draining and Improving of the Bogs and Unprofitable Low Grounds, and for the easing and despatching the Inland Carriage and Conveyance of Goods from one part to another within this Kingdom'.

Eighteen different schemes were authorised to be carried out under local commissioners or Undertakers but no funds were made available and only two schemes were actually initiated in the years immediately after the passing of the Act. It was, however, subsequently invoked as authorisation for other schemes in the years that followed and it marks the beginning of the Canal Age in Ireland.

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