About 6 months ago a friend popped an article through my letterbox and it has been percolating around in my mind ever since. From an issue of Horizons, the University of Cambridge’s research magazine, the piece focuses on the East of England and considers climate change and flooding. It questions whether manmade barriers are the best coastal defence and with predicted rises in sea level of up to 1.5m by 2100, in the future these hard defences would only have to be built bigger and higher and become more conspicuous.
The East coast is a low lying ‘soft’ coast. The energy of tides and waves brings silt and clay that accumulates near the shore. As the water shallows, the particles are trapped by salt tolerant plants and salt marsh begins to form. Salt marshes are a valuable environmental resource as they can absorb and bury carbon from the atmosphere and offer habitats to unique plants and animals
Although salt marsh changes daily with each tide, and is particularly vulnerable to coastal erosion, tidal surges and flooding, the article, written by Sarah Collins, suggests that it could actually provide a more sustainable option to hard, concrete defences and act as a protective barrier, buffering wave actions, reducing their height and therefore their potential for damage. It has been shown that a narrow strip of salt marsh 40m wide reduces wave height by 20% and strip 80m wide can reduce waves to zero – the saltmarsh is able quite literally to swallow the waves.
Here in Wells, low-lying reclaimed farmland is protected by man-made sea defences – high sea walls that were built to protect the land in the aftermath of the flooding of the 1953 tidal surge. These walls do protect the land, but they also create a barrier, stopping the shore from moving inland and squeezing the saltmarsh between the sea and our coastal defences.
To act efficiently as natural flood defences the sea and salt marsh needs to be able to move landwise naturally and freely and with the projected rise in sea levels it is unlikely that the coastline will stay as it is at the moment.
The issue of the changing coastline has occupied my mind for some time now and I have been considering how I could make a piece of work that considers these issues. The drawings here are some of my first ideas and explore ideas around the destructive tide, inundation and shifting boundaries. Next time I’ll show you my next steps in this project.