New Crinan Canal Locks (Large File Size Pictures)
Posted: Sun Feb 26, 2023 5:13 pm
Just had a tour of the lock leading into the basin at Crinan. Quite fascinating listening to the changes in lock gate design and some of the environmental activities underway.
The lock gates are all steel and built in the UK. The main difference is that they are fully supported on their hinges at all times, unlike the old gates. The wooden balance beam is for show and not needed on these electric screw driven gates (not hydraulic). The old gates, once closed and their buoyancy lost as the water level dropped, rocked forward and sat on the cill which put a lot of force onto the hinges. Now the gates push against the cill edge and do not rest on the cill at all. The gates have numerous pads at the hinge side and opposite side spread along the faces. When the gates close the pads push against their opposite number either in the hinge or on the other gate. The pads are engineered to not compress by any noticeable amount and last for around 25 years and can be changed in situ. I thought the bolting, using double Nyloc nuts was very suspect considering the multitude of reliable securing devices on the market. Running around the hinge side, bottom edge and on one of the gates contact face, is a large rubber seal which will compress to hold back the water. The gates require great accuracy to set up. There are 13 known leaks along the banks, I forgot to ask if they had plugged them up.
There was a lot of work on the environment side to make sure that the silt and water did not damage the moine as they drained the canal. There was a survey of the amount of water to be dumped and that was passed to external experts who decided that it was not harmful. There are a number of plugs running along the canal and they have been connected to new operating screws to be able to lift at any time. The basin at Crinan and along some of the reaches has an obvious build up of silt and debris but they will not be removing any, except the stuff that is a hazard. The reason is that they don't have the land capacity to store the dredged material or the budget to analyse it and take it away for dumping elsewhere. It does appear to be a lost opportunity. They captured all the fish and the total count was very low as apparently the canal has a dearth of nutrients in it which is not that good for aquatic life. On the banks, they had to review all the fauna and make sure that it was preserved. A lady on the tour who retuned to the area after a long absence said she was surprised at the quantity of flowers and butterflies on the banks. They mow around the orchids for example, so that they are preserved.
All in all, the new gates and works appear to be a reasonable attempt at preserving the the life of the canal. They did say that while the canal is listed as something or another (can't remember) it does not have to be preserved as a museum piece, hence all the gates and bridges can be in any style.
Factoid Time. Loch Ness is officially a Reservoir because the canal maintains the level artificially high. It therefore needs to be managed to ensure that over topping and embankment / dam collapse is not a risk to people living in the area.
The lock gates are all steel and built in the UK. The main difference is that they are fully supported on their hinges at all times, unlike the old gates. The wooden balance beam is for show and not needed on these electric screw driven gates (not hydraulic). The old gates, once closed and their buoyancy lost as the water level dropped, rocked forward and sat on the cill which put a lot of force onto the hinges. Now the gates push against the cill edge and do not rest on the cill at all. The gates have numerous pads at the hinge side and opposite side spread along the faces. When the gates close the pads push against their opposite number either in the hinge or on the other gate. The pads are engineered to not compress by any noticeable amount and last for around 25 years and can be changed in situ. I thought the bolting, using double Nyloc nuts was very suspect considering the multitude of reliable securing devices on the market. Running around the hinge side, bottom edge and on one of the gates contact face, is a large rubber seal which will compress to hold back the water. The gates require great accuracy to set up. There are 13 known leaks along the banks, I forgot to ask if they had plugged them up.
There was a lot of work on the environment side to make sure that the silt and water did not damage the moine as they drained the canal. There was a survey of the amount of water to be dumped and that was passed to external experts who decided that it was not harmful. There are a number of plugs running along the canal and they have been connected to new operating screws to be able to lift at any time. The basin at Crinan and along some of the reaches has an obvious build up of silt and debris but they will not be removing any, except the stuff that is a hazard. The reason is that they don't have the land capacity to store the dredged material or the budget to analyse it and take it away for dumping elsewhere. It does appear to be a lost opportunity. They captured all the fish and the total count was very low as apparently the canal has a dearth of nutrients in it which is not that good for aquatic life. On the banks, they had to review all the fauna and make sure that it was preserved. A lady on the tour who retuned to the area after a long absence said she was surprised at the quantity of flowers and butterflies on the banks. They mow around the orchids for example, so that they are preserved.
All in all, the new gates and works appear to be a reasonable attempt at preserving the the life of the canal. They did say that while the canal is listed as something or another (can't remember) it does not have to be preserved as a museum piece, hence all the gates and bridges can be in any style.
Factoid Time. Loch Ness is officially a Reservoir because the canal maintains the level artificially high. It therefore needs to be managed to ensure that over topping and embankment / dam collapse is not a risk to people living in the area.
