Monday, 15 June 2015

The Culloch Burn

The Culloch Burn is a stream which flows into the River Avon in Slamannan, a village in the middle of Sliabh Mannan.  The Stirlingshire Avon is unconnected, except by name, with the considerably more famous river running through Shakespeare's Stratford.  In fact the name Avon derives directly from the Celtic word for river and there are several examples of the unimaginatively named 'River River' throughout the United Kingdom.

Although the village is more than 400 feet above sea level it lies in a natural basin in Sliabh Mannan, meaning the only ways out are all uphill. In consequence the lowest parts lie within a natural floodplain and any drainage bottleneck is vulnerable to being overwhelmed after heavy rain.

People who do not live near the headwaters of upland streams find it hard to take warnings against flooding seriously, as I have had occasion to remind local Council planners before now.

The above photograph shows the Culloch in a dry season. That's right, you can't see it. You can however see its banks just behind the electricity pole. You might even wonder how such a little burn has cut so deep a channel and why constant erosion is regularly changing its winding course.

An official will come out on a sunny summer day, observe this trickle of water and condemn as fantasists your correspondent and others who advise them to be careful when zoning areas for housing development.  Such a feeble watercourse, he thinks, could not flood a child's paddling pool.

Well the next photograph shows what can happen if it rains for a couple of days. You can still see the long rushes that mark the course of the Culloch, but now the burn is about a hundred yards wide because it has burst its banks and inundated the flood plain. 

Turn left from where the first two pictures were taken and you can just make out the outskirts of Slamannan, towards which the Culloch is flowing.  It is there where it joins the Avon as, in normal circumstances, a tiny tributary of a small river.

But when the Culloch looks like this, the confluence obviously poses more of a problem.

Now imagine what is likely to happen if additional housing were to be constructed on the southern outskirts of Slamannan, increasing the flow of surface water by reducing natural absorbency and also increasing domestic drainage into a system as volatile as this.

You're right.  Not smart.  So if in spite of my advice such developments go ahead, please remember:


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