Transcript: VFT 1: South Uist - Interview with Johanne
Ferguson, Scottish Natural Heritage, Operations Manager
Outer Hebrides Tuesday 22nd January 2013
Question 3: How has sea level rise and coastal erosion affected the machair?
Well it continually affects the machair. At the moment we are in a period of sea level rise and that means
we’ve got an increase in erosion at the dune front. What happens is, particularly over winter time, during
the storms, the sand at the front of the dune gets eaten away and then moved around and deposited
further along the coast.
If it’s in a neutral phase then you’ve got a difference between summer and winter but the coast is pretty
much static. Just now, because sea level is increasing, the sand dunes are actually moving backward, so
these will roll further inland as the material gets blown over the top and your crofters lose some of their
common grazings and some of your archaeology is exposed or lost. And that’s fine up to a point, except
that there are times when there is no space for the dunes to move further inland either because of the
system of land ownership that we have just now, particularly in relation to crofting where crofts are static
and a particular crofter could end up losing all of their land and have no space to move further back. So, it’s
our systems that are the way of this natural process adapting to the rise in sea level.
In addition to that there’s a problem with the drainage system, particularly in areas like South Uist. The
drains, or canals were put in, well we don’t actually know when, but at least hundreds of years ago and at
that point in time there was more of a drop between where the water was and the sea level so therefore
the water drained from where it was flooding to the sea. Whereas now there’s far less of a drop so the
drains are becoming quite inefficient and that’s only going to get worse into the future. As sea levels
continue to rise it’s going to be more difficult to drain these flooded areas.
Some flooding is natural, for instance in the winter time we have on the machair what we call ‘seasonal
lochs’ and these form just behind the sand dunes, and after a period of rain you’ll suddenly have a seasonal
loch appearing. It might last for a few weeks or a few days and then disappear again as the water table goes
down a wee bit. So they are quite transient, so that’s quite natural but people say that situation’s got worse
over time and one of the concerns they have is that when it comes to ploughing, in the spring, if the
seasonal lochs haven’t drained away then it’s quite difficult for them to plough in the same time as they did
in the past.
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