English: Ironbridge flood defences A closer view of the flood defences seen in 292032. When not required these can be folded down flat and carried away for storage. They can be erected quickly, rather like deck-chairs and are free standing, relying on the pressure of the water to hold then in place. A plastic membrane is laid over them to make them waterproof and this in turn is held down by laying the chains visible on the footpath along the bottom of the membrane.