Friday, 21 March 2014

Dredging or sponges?

This morning I was on a panel as part of a Radio Kent discussion on what can be done to reduce flooding in the future. The debate was set three months after the floods that affected areas along the length of the River Medway and were felt especially badly around Yalding and in the centre of Maidstone.

On the panel with me was Richard Knox-Johnston, Vice President of CPRE in Kent, Professor Richard Ashby and Sue Chalkby an East Peckham resident who has been affected twice in the past and was representing the East Peckham Flood Group.

I started with setting out three principles:
  1. Work with nature
  2. Flooding can't be totally avoided and climate change will make our weather more extreme more often
  3. Changes in one area will often affect other areas

The majority of start of the discussion centred around whether it was reasonable to have a dedicated tax to support flood prevention, either paid for by the nation as a whole or by people on flood plains.

We had a useful discussion about sponges. Using upland areas as natural sponges by planting them with woodland which causes the water to drain into the ground 67 times faster than grass land. Also using bogs and wetlands to promote water absorbtion.

Keeping water from draining down and away through the rivers too quickly seemed to have a consensus. The rivers have a limited ability to drain water and while it needs to go, it has to drain in a way that doesn't do more damage.

Dredging didn't get a mention this morning but the advice from most experts is that it would have no place on a river such as the Medway. Indeed, dredging increases the flow of water but causes problems at pinch points such as bridges. As the south bridge in the centre of Maidstone had to be closed to even pedestrians as they were worried about the effect of water pressure on it, dredging upstream would have increased this pressure further, increasing the flooding in the town and putting more pressure on the bridge itself.

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