How the Environment Agency got flood risk management wrong

As the controversy over flood risk management continues apace, engineer David Noble, formerly a senior manager with the Environment Agency s predecessor bodies and more recently a consultant, who was awarded the OBE in 2002 for services to flood defence a

As the controversy over flood risk management continues apace, engineer David Noble, formerly a senior manager with the Environment Agency's predecessor bodies and more recently a consultant, who was awarded the OBE in 2002 for services to flood defence and land drainage, argues that there is a conflict between the agency's river management responsibilities and its duties to wildlife.

THE Environment Agency's £10million spent on flood defences for St Ives and planned for Godmanchester is not wise investment unless accompanied by other river management work, including dredging and cutting back vegetation.

I agree that taxpayers' money must be well spent. But to spend only £3million on dredging and £8million on channel vegetation control from an annual budget of some £600million is derisory [figures from an Agency 2007 report].

And this is at a time when £15million of 'flood' money can be allocated to provide a compensatory wetland for birds alongside the Hundred Foot Washes.


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It is time for the agency to re-assess its priorities and to minimise flood risk through a substantially enhanced channel maintenance programme.

I take issue with Peta Denham, of the agency, in a recent letter to The Hunts Post. She refers to the past practice of dredging channels to a programme, which she dismisses as having been a waste of time and money, an approach now overtaken by more scientific assessment.

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The practice was introduced as a measure to prevent flooding, as an alternative to dredging only when channel capacity had been severely reduced, and often, only after flooding had taken place.

It was based on a detailed understanding of the river system, through condition monitoring and the extensive operational experience of long-serving employees. In saying that dredging is not sustainable, the suggestion is that the agency will preside over increasingly silted and vegetation-choked channels - and therefore increased flooding.

Along rivers like the Great Ouse the floodplain plays an important role in both conveying and storing floodwater. But a well-maintained channel will carry greater flow within its banks. This effectively saves the floodplain capacity for the more severe event.

Whenever flooding takes place, locals claim that the offending river is no longer maintained. The agency's standard response is that dredging and other maintenance would have made no difference to the flooding. This is not the case, and it conflicts with the most basic principles of flow conveyance in channels. It is particularly significant in the flatter gradient rivers in this area.

The effects of the policy can easily be seen - obstructed channels in the Hundred Foot Washes, a major flood control facility, virtual abandonment of many channels alongside the Great Ouse and the neglect over many years of Alconbury Brook. This takes water from Alconbury and Alconbury Weston, which have suffered flooding in the past and still await improved protection, despite over £100,000 being spent on fees in seeking a solution.

How, if indeed dredging is not sustainable, does the agency intend to maintain navigation on the Great Ouse, for which it has a legal responsibility.

The problem was foreseen when the Environment Agency was set up in 1995. Many people believed - and they have been proved right - that operational activities would not sit comfortably within a predominantly regulatory body charged with environmental protection.

The policy for maintaining river systems is now driven substantially by environmental concerns. The agency has become over-hesitant in dredging channels, removing reed beds and controlling vegetation in channels and at the bankside. These essential tasks considered as having an adverse environmental impact, with conservation concerns frequently overriding river flow requirements.

It is time for the agency to re-assess its priorities and to minimise flood risk through a substantially enhanced channel maintenance programme.

* We hope to publish the Environment Agency's response next week

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