Feeding the Grand Canal

Since it was first conceived in 1755 to the time it was complete in 1804 from Dublin to the Shannon, one of the main challenges facing the creators of the Grand Canal was water – feeding water to the canal and ensuring it stays in the canal.  Having sufficient depth to enable the transport of goods and people was key during the commercial era.  Today ensuring depth and supply is crucial to attracting boating tourists to our towns and villages, located along the canal.    

The stretch of canal between Locks 18 and 19 in Lowtown is the summit of the Main Line, from there to Dublin, Shannon and Athy is all downhill.  The highest place is Naas, which is reached by ascending another five Locks on the Naas Canal. 

Today, the Grand Canal in Kildare is replenished by the Miltown Feeder channel near Lowtown, from where water flows east, south and west; further east, at Soldier’s Island, water comes from the Corbally Harbour Spring via the Naas Canal; to the east of Sallins is the Moonread Feeder; another source is the Morrell Feeder channel near the border with Dublin.  Water descends from each level and eventually on to Athy, Dublin and the Shannon.  Boats navigating the locks send water down to the next level, Waterways Ireland staff manage the levels by racking it through the Locks and using back pumps to bring the water back up to a level, where needed.   

The Dwindling Channel

Changes in our climate are causing the heating of our waterways leading to more evaporation during the summer months than it did in the past, but another challenge is the dwindling size of the channel itself.  The space for storing water is getting smaller because we have allowed  invasive plants to escape from our gardens and take over our canals.  During the summer, they grow unchecked.  When these plants die back during the autumn and winter months, their detritus causes a build-up of silt at the bottom of the channel.  A comparison might be the accumulation of leaves creating compost, the silt is serving the same purpose on the bottom of the canal – fertile ground for the invasive weeds.  Examples of where this is happening are the Naas Canal, Naas Harbour, Soldiers Island and the canal in Sallins.  Feeders that are damaged or do not have a method to remove silt also add to the accumulation at the bottom of the canal.  Examples are the large accumulation in Corbally Harbour that has grown into a Silt Island over many years and the Inner Harbour in Naas where boats go aground because of the silt build up. 

Another aspect of climate change is heavy rain at times, with all water channels filling up quickly.  When there is insufficient capacity to contain the water, the area floods onto adjacent land and homes. 

Holidaying on a boat and communing with nature can be an enjoyable experience for everyone, but not so, when one is forced to spend time in the water clearing weed off the Propeller or forcing the boat through silt and weed.  The result is dissatisfaction for individuals and damage to their boats – not a pleasant holiday.