Going over old ground

I’ve been blogging for more than 20 months now and I have an expanding readership. In addition, I have an increasing number of posts that I’m certain nobody (least of all me) is ever going to wade through. Though I do say so myself, some of my early posts were quite good and it seems a shame to let them languish deep in the snail shell of obscurity. I have, therefore, decided  that from time-to-time I will revisit some of my old writing and bring it to you with a fresh eye. So here is my first dip into the past…

Back in June 2012, Aberystwyth (a town just up the coast from us) was flooded following a reported 10 inches of rain in the hills above the town. This week the town hit the headlines again, because the promenade has been badly damaged by storms. I lived in Aberystwyth for many years – more than three of those right on the seafront. There were days when we couldn’t use the front door, and sometimes cars parked outside did get pebble-dashed, but we certainly never experienced anything more severe. And, the town was never flooded. But when I was there, the floodplain was taken up by playing fields and allotments, so it didn’t matter if the river burst its banks. These days, the area is covered in houses, shops and the new offices of both the county council and the Welsh Assembly.

Anyway, when the flooding happened in 2012, I wrote the following:

…it is remarkably short-sighted to continue to build on floodplains. First because the risk of flooding is greater there and, second, because these areas have flooded historically, they have wonderfully fertile soil. Surely we should be using this brilliant natural resource to grow things… even if crops get inundated sometimes, people and their homes won’t.

But it’s not just about where we build houses and businesses, the problem with flooding is that it’s really caused by what’s upstream in the river catchment and how quickly water moves through the landscape. If the land is wooded, lots of rain is intercepted on its way down to the ground, so it is slowed in its journey to the surface and may even have the opportunity to evaporate and return to the air. All vegetation intercepts rainfall, but trees with leaves probably do it best because they have a big surface area. Not only that, but trees create deep permeable soils, with their roots penetrating the ground and lots of organic matter from their fallen leaves acting like a sponge. The more wooded the upper catchments of our rivers, the slower the water moves through them and the more buffering there is from flooding. The opposite is equally true – make the ground less permeable and water moves through it quickly, all arriving at the rivers in a very short time and resulting in flooding. So, roads and storm drains and buildings and concrete yards and patios and field drains all contribute to flooding by speeding up the movement of water through the landscape. Grassland is not as good at intercepting water as woodland, and shallow rooted plants are likely to be associated with less permeable soil than deep-rooted ones.

Let's encourage water to soak into the soil

Let’s encourage water to soak into the soil

Whilst the latest flood could not have been avoided no matter what the land use in Ceredigion, it could have been reduced if we had more woodlands (especially in the uplands) and a generally more permeable landscape throughout the river catchments. And many of us can do something about this… if you have a garden, you could make sure that the ground is permeable  – so no more patios and paved driveways, consider gravel and grasscrete. Build up the organic matter in your garden – this will help to hold water and be an effective defence against both flood and drought. Install water butts, so that you catch as much of that precious commodity as you can when it’s plentiful and prevent it literally going down the drain. And, finally plant trees and shrubs to intercept the water, root deep into the soil to allow water to percolate down and provide shelter from sun and wind which will dry out your garden anyway.

As I watch the pictures on the television of more and more flooded areas in the UK, I can’t help wishing that planners would take into account how water moves through the landscape, so we can avoid some of the damage, loss of property and personal distress.


My original post Water, water everywhere can be found here.

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