Emmet Stagg (Kildare North, Labour) | Oireachtas source

Deputy Murphy made a point about the silting of the main channel of the River Liffey, which provides drainage for the entire county, especially the north. That is a very real issue because the height of the river is affected at times of high water and the backup into the drainage streams is also adversely affected. I spoke at one time - I am not sure whether to Mr. Dunney or to another of the engineers - about the possibility of Venturi turning of the drains as they meet the main flow to draw them out, even if the level was higher. That would be very effective, and certainly would be cost-effective because it would cost very little but would save a lot.

The actual silting of the river is a serious matter. It is very good for angling, in which I have a certain interest, but from the point of view of drainage it is bad. Trees fall across the river and mushrooms grow on them before they eventually disappear, perhaps in a bigger flood.

Some of them have been there for ten or 15 years, right across the main channel of the river. There is an inherent flaw in draining all of the main streams into the channel to alleviate flooding but not dealing with the main channel itself. There is a lot to be said about starting at the bottom and moving upstream because one knows what one is dealing with. When one starts at the top, one might be causing flooding further downstream in areas that were not flooded.

The contour mapping that is being carried out by some engineering companies is being taken up by the insurance companies and causing difficulties. It gives a very false picture because there are areas that are thoroughly well drained but which might have a low contour point. Such areas are deemed by the contour mapping to be flood plains or areas not suitable for building on. We need something from the official authorities to counter those maps on behalf of the citizens who are adversely affected. Some form of letter should issue about specific areas that may have a low contour but which would not necessarily be prone to flooding. Perhaps the council could indicate that it has no plans to alleviate flooding in such areas because they are not deemed to be at risk.