Garret Corner, Chair of Inveraray Community Council has now had detailed discussions with Scottish Water’s chief operational engineer on the post-Christmas flooding suffered by the town.

At the time, Scottish Water said that the cause was a volume of waste oils and fats from Christmas dinners poured down sinks into the town drains, coagulating there, collecting other passing items and clogging the system. Given the number of hotels in quite a small town this argument was one that ForArgyll found very plausible, particularly when the company said that it had had the same experience of accumulated fats in the system at the same seasonal time last year.

The local press however went for opinion rather than evidence and encouraged locals to blame the hapless Scottish Water instead of considering alternative possibilities. This is dated, cheap and irresponsible journalism. Argyll deserves better.

After Mr Corner’s exhaustive discussions with the Scottish Water engineer and his examination of the evidence given to him he has told For Argyll that he is now convinced of Scottish Water’s argument on this and that residents of Inveraray will need to revise their habits on the disposal of waste oils and fats.

The Scottish Environment Protection Agency is about to start requiring hospitality industry operators in Inveraray to declare and prove how they dispose of their waste oils and fats. If they cannot do so they face severe penalties.

For general information, this is what Mr Corner discovered about the operation of the Inveraray waste water system and the cause of this recurring flooding.

The drainage system installed by Scottish Water in Inveraray has a flood chamber with a valve which legally discharges water into Loch Fyne when the chamber is overwhelmed with flooding. This prevents waste water backing up through the manholes in the streets as it has done before.

In the latest post-Christmas incident of flooded drains, Scottish Water’s engineers found this release valve completeley clogged and sealed up with fat and unable to release. On previous occasions engineers had found the system clogged with fats before the waste water could even reach the release valve in the flood chamber.

According to Mr Corner, Scottish Water have now upgraded their maintenance procedures in several ways so that they can prevent flooding in the first instance and contain it in others.

• The system has two pumps – a ‘duty’ pump and a back-up pump. Previously, if the duty pump went out of service the back-up pump would take over. If that too went down, leaving the system with no operational pump, Scottish Water would send out an engineer. Now an engineer comes out as soon as the first pump stops operating.
• Routine maintenance of the system now includes inspection and testing of the release valve in the flood chamber described above.
• Scottish Water had hoped to install CCTV in the drainage system before Christmas 2008 and will now get that installed by Christmas 2009 at the latest. This will let their engineers see if the system is becoming clogged up with fats and possibly identify the source of these fats.
• The company may also put dye down different parts of the system to discover where the major rainwater inputs come from in storm conditions. They will then consider diverting such sources direct to the loch as this is simply rainwater.
• In a major advance, they have sorted out the problem of system invasion by seawater during high and equinoctial tides. In the past, after such invasions up to 80% of the water remaining in the system was seawater. This becomes hydrochloric acid and eats the impellers and other metal parts. Now, regardless of the state of the tide, the system carries a stable 15% seawater.

Mr Corner also established that the recent unpleasant smells experienced in the town do not signal a return to the problems of the past. These recent smells were the result of the company having to pump out the smaller accumulations of fat from the system once engineers had removed the major fat obstructions by more muscular means.

It is to the credit of Garret Corner and of Scottish Water that they sat down together to examine the evidence for the cause of this latest flooding and to clarify the operation of the system for the benefit of residents.

In Mr Corner’s experience this certainly indicates that Inveraray (and the town is not alone in this) needs quickly to change its traditional habits of waste oils and fats disposal – in its own interests.