The Cork Bund

Building the Cork Bun
In a farmer’s field somewhere to the north of Macroom, Co. Cork, there is now a heap of soil where there was no heap before. Once it’s formed into the right shape, compacted & seeded, it is hoped that this heap will become Ireland’s first purpose-built Natural Water Retention Measure (NWRM). It will be a bund. (A bund is stone or earth formed into an embankment to hold back water).
There are other bunds in Ireland. A bund that’s about 4 meters high & 100 meters long was recently constructed as part of a huge flood defense scheme for the town of Clonakilty in West Cork. Another large-scale bund delineating a flood plain on the banks of the Blackwater is visible from the main road that skirts Fermoy in North Cork. The bund that we’re making in a field near Macroom, however, is different. Our bund is small and made only from locally occurring soil. It will not retain the whole flood, nor will it retain water for the days & weeks that the big bunds hold back. It will retain the critical portion of the flood, & only for a critical duration of about 12 hours – not long enough to inflict anoxia on the soil or reduce field productivity once waters recede.

Our Cork bund will demonstrate how small natural structures may help to retain floodwater diverted from a stream running along the field’s edge, when the stream begins to swell from winter storms or summer cloud-bursts. As the storm passes, the water will slowly drain through a little pipe at the bund’s base, and flow to back into its stream. The aim is cut the top off of the hydrograph for the storm flow & protect vulnerable settlements downstream from receiving all the storm’s runoff at once.
We, in the SloWaters project, do not want to capture all the storm flow in one field. We want water that falls during a shower, or rises up from the ground, to take a little longer to get down to the sea – or down to a town – & we want fields & forests throughout the catchment to hold on to the water: each in their own time letting it dribble down to the channels.
Currently our bund is a messy pile of soil, which was very kindly donated by the local council while they cleared silt & soil from roadsides to reduce flooding on the roads. When the big showers come in a few months, the soil that was blocking drains & causing the roads to flood will be helping to temporarily flood a farmer’s field. In time, fields throughout Ireland may be utilised for flood management.