IT IS good to know that MP Tim Farron is taking flood risk at Windermere and the River Leven seriously (Gazette, November 29, 'Lakes flood plan goes to Whitehall').

He is seeking clarification on costing from the Environment Agency for a £3.6 million package of works to include dredging the outlet channel of the lake, building defence walls at Newby Bridge and improving the overspill mechanism at Backbarrow.

This package of works would, unfortunately, be ineffective. The Environment Agency’s reports show that the peak lake level in 2009 was 2.9 metres higher than the lake datum, whereas dredging the outlet channel by one metre, as proposed by the Environment Agency, would reduce the lake level by 0.22 of a metre only.

Dredging by an additional one metre would reduce the lake level by an additional 0.1 of a metre only. The outlet channel would refill with sediment, so that any reduction in lake levels would be lost and dredging would need to be repeated periodically to recover the original effect. Any minimal benefit would be overwhelmed by the effects of climate change.

The effectiveness of the works at Newby Bridge and Backbarrow would be minimal.

The impact of dredging would have severe environmental consequences and would be in breach of the objectives of the Water Framework Directive. Necessary ongoing channel dredging and maintenance would repeat this damage on each recurrence.

It will be interesting to hear what the Environment Agency says in answer to Tim Farron’s questions about costs, because the package of works is not only insufficient and environmentally unacceptable, but also has been substantially under-costed by the Environment Agency.

Fortunately, there is a solution that is effective for all, future-proof against climate change and without the environmental impacts mentioned above.

A pipeline could be installed from Lakeside back into the River Leven just south of Backbarrow, which would siphon water from the lake in advance of peak rainfall in sufficient quantity to avoid damaging flooding.

Although agreeing that it is the only fully effective solution, the Environment Agency has so far over-engineered and over-costed this solution. The next step must be for the Environment Agency to assess the solution properly.

Paul Wrobel

Cunsey

Colin Musgrave

Windermere