I'm glad this has been brought up and hopefully some BFers can offer their opinions. I have been visiting Cuckmere Haven and the Cuckmere Valley for nearly 30 years, long before I became a birder. It is a gloriously beautiful downland landscape.
As I understand it the owners, The National Trust, and The Environment Agency, who manages the coastal defenses, want to ALLOW the valley to flood. This would not happen instantly but would result, maybe after a period of years, probably during a period of prolonged heavy rain combined with storm conditions and a very high tide. The proposal is not specifically intended to benefit birds or wildlife but rather to save money on the exorbitant costs of maintaining the shoreline and river defenses which is vulnerable to erosion and flooding. Indeed I have seen the whole valley beyond Alfriston and Litlington flooded in the floods seven or eight years ago. I have come round to the view that due to climate change and rising sea levels the Cuckmere Valley will probably be one of the first places on the south coast to "go under" as sea levels rise. So it is probably inevitable that the lower valley will flood whatever is or isn't done.
It is something of a political "hot potato". Most of the locals want to keep it as it is; it is a much loved landscape and a tourist attraction. The town of Seaford and the local council are mostly against allowing it to flood. The SOS is, I think, in favour of allowing it to flood because they see it as attracting more birds. My question is will it really attract more birds (it is already pretty good) unless it is actively managed to do so? I am not aware that active wildlife management is part of the proposal. They seem to be a bit cagey on this.
Views from ecologists and scientists I think are especially needed.
It is easier to criticize somebody else than to see yourself. G Harrison