The Barrage will impound the rivers Taff and Ely to create a 200-hectare freshwater bay and waterfront extending 13km. It is one of the largest investment and engineering projects currently taking place in the UK and is managed by the Cardiff Bay Development Corporation.

“Because we anticipate algal problems, we expect that the impoundment will be designated as a Eutrophic Sensitive Water under the EC Urban Waste Water Treatment Directive,” Martin Mills, area environment planning manager at the Welsh EA told edie. “But the process of designation will take some time.”

Such a designation would require controls on inputs of nutrients from qualifying upstream sewage discharges in the rivers Taff and Ely catchments. The EA is planning ahead for the Eutrophic designation and has succeeded in getting Welsh Water to include nutrient removal at its five sewage treatment works on the Taff and Ely in its budgets for 2000-2005.

“We’ve raised nutrient removal as one of the highest priorities for Wales,” said Mills.

The Barrage’s impact in fish population is of equal importance. “It will be a barrier to fish migration,” said Mills. The EA has stipulated that a fishpass be included in the Barrage plans, but it is unknown whether it will work. “Nobody knows how successful that fishpass will be. There’s already a stocking programme in place to maximise the number of adult salmon returning to the River Taff,” said Mills.

The stocking programme has been in place for several years as an effort to mitigate the Barrage’s future impact. The agency’s research suggests that it will be unable to know whether the Barrage is reducing salmon levels until there is at least a 37% reduction.

The EA’s predecessor, the National Rivers Authority, opposed plans for the Cardiff River Barrage. Approval came after it was backed by a government-sponsored bill. “There are still significant environmental risks and costs related to the project,” affirmed Mills.

Cardiff Bay Barrage will be used for non-immersion sports, including boating and fishing.

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