Floods in the garden

As the Christmas guests departed and the old year stumbled into its last few days, I was looking forward to a period of quiet contemplation, one or two pleasant walks, and a chance to check out upcoming tasks in the garden.

It wasn’t to be.

Just as the cheerful farewells were being said and the house was restored to some sort of order, two things struck. More or less simultaneously.

After a day or two of feeling unwell, Dr G and I tested positive for COVID-19. We’d had a good run. This was our first time, despite significant exposure to the virus. Over the next week we experienced a shifting array of unpleasant (sometimes puzzling) symptoms, brief remissions, and headache filled days

This wasn’t to be our only challenge however.

On the night of 29/30 December it rained heavily and continuously, hammering on the slate roof in the darkest hours of the pre-dawn. We woke up to a roaring Pennyland Burn that was already bursting its banks, flooding into the garden pond and then back into the main watercourse further downstream. A whole section of the garden was dangerously impassable, engulfed in water moving at speed.

The two events combined in their effects. Feeling unwell whilst at the same time monitoring the rising levels of the burn created an odd sense of fragility. Nothing could be done. We simply had to wait for the rain to stop and the water to subside.

On Hogmanay, that began to happen. Over the next few days, when COVID allowed, I was able to walk round the New Year garden and survey the damage, as the post-flood scenario gradually revealed itself.

The most mature areas, on higher ground close to the house, were largely unaffected. It was on the flat, lower places close to the water that the damage was everywhere to be seen.

This section of the garden is three parts encircled by the Pennyland Burn and in some spots may even be below the streambed itself. So it is vulnerable and the water flowing over it must have been 2-3 feet deep. It’s also an area into which I have moved more recently, as new planting space becomes more limited elsewhere.

On a first look, most apparent were the thick layers of silty sand that had deposited in swirling patterns across the borders and on the grass. This had completely obliterated some low growing plants, which we now hope, without much confidence, will eventually reappear. Larger specimens such as ferns, hellebores, epimediums and daphne had caught the flood full-on and been flattened or strangled by debris suspended in the water. Leaves, long grass, roots, twigs and branches in large quantities were entangled in foliage or washed up in drifts against trees and low walls.  It was a sorry sight.

As conditions and energy levels allowed, I slowly began the clear up. Removing the debris, untangling the worst affected plants, raking the silt and gravel, picking off the twigs and branches and removing these to the woodstore for drying.

I was astonished just how quickly things began to recover. A few sunny interludes made a difference too. But then the temperature dropped for a second spell this winter. The ground and pond froze, further inhibiting the clear-up.

At this point I found myself thinking back to how the Dumfriesshire garden had been created.  It was the late 1990s when I was delivered the opportunity to create a garden where none had existed before, in an area largely surrounded by water, and heavily overgrown. 

I look back now and shudder at my combined naivety and arrogance. I could see that the curve in the burn was in effect an incipient ox bow, which would one day be cut off. In periods of high water, the torrent was taking a direct line to a lower point and cutting out the sweeping bend. When levels were lower, the area which the flood water crossed could be seen as permanently damp and was home to rashes and cotton grass. Taking up a large amount of space in the centre of the emergent garden, I took the view that it needed to be ‘improved’.

Over a couple of evenings a digger was brought in to scoop out the wettest area, and the resulting spoil was piled up on the banks of the burn to restrict further water ingress. A pipe was installed from the burn to the excavated area, which quickly filled up as a large garden pond came into existence, the water held by the silty mud beneath. The addition of another pipe at the lower end allowed excess water to flow back into the burn.

Over the years, the pond has been a haven for wildlife. It teems with frogs in spring, is a permanent feeding spot for the heron, home to migratory eels, and a favoured residence of damsel and dragonflies. In and around it I have planted  irises, rheums, primulas, rodgersia and darmera.

It’s a terrific ecosystem that has been protected by the raised banks around the burn. Now in 2023 however, flooding is becoming more common. The banks are no longer working and the bordering plants are exposed to periodic bursts of heavy, flotsam-laden flood water.

More significantly, the flood residue is affecting the depth of the pond itself, which is getting shallower as silt, leaves, twigs and plant matter build up on the bottom. Also, with the hotter summers, the burn can be reduced to a tiny trickle for several months at a time. Since the in-flow is not enough to maintain the pond water level, large areas are more and more prone to dry out.

So now I need to re-think this part of the garden. I have bought willows and aspen to plant in areas where the effect of flooding is present, but still limited. These trees will cover a large area currently under grass, but where moss increasingly thrives. 

As to the pond, who knows? Perhaps native willows and alder will colonise it without my intervention. In between I’ll add more bog plants. The pleasurable sight of moving water caught on the breeze will gradually diminish. But the compensation will still be a pocket of rich biodiversity.

As I muse in this way, I am mindful that others, locally and all around the world, are suffering much more harshly from the effects of flooding. Here in Nithsdale, the damage to homes, livestock, roads and infrastructure has been extensive in the past few weeks.  One mustn’t agonise about a garden.

At the same time the garden teaches us. It’s a microcosm of a bigger issue. ‘Hard’ solutions to water management– raised banks, bunds, concrete walls – are widely contested by environmentalists. Nature based approaches increasingly gain favour: re-wetting peat bogs, slowing down the flow in river catchments, returning flood plains to their original purpose.

For now, and within a few weeks, the Dumfriesshire garden has recovered, just as the COVID-19 was shaken off. We see it here on a sunny day, emerald green and sparkling.

But for how long? Surely these events will recur. All manner of mitigations are possible. But the problem truly lies ‘upstream’. With climate change itself.