THE company responsible for constructing the A3 Hindhead tunnel was fined £28,000 last Friday for polluting controlled waters with silt.

Balfour Beatty Civil Engineering admitted two offences - under section 85 of the Water Resources Act 1991 - at Guildford Magistrates Court. Balfour Beatty was also ordered to pay £9,477 costs, making a total £37,477.

In sentencing Balfour Beatty, magistrates took into account the company's early guilty plea and cooperation with the Environment Agency. They also recognised the company had not gained financially by allowing pollution to occur.

However, magistrates found that management failures and lack of proper supervision had contributed to the incidents.

The offences involved causing silt pollution to enter the Milhanger and Hammer watercourses between June 3 and 6 last year, and polluting Nutcombe Valley stream ponds between November 22 last year and January 15 this year.

Regarding the first offence, the Environment Agency had given Balfour Beatty permission to use an existing highways drain feeding into Milhanger Lake, providing water would be uncontaminated and silt free. The agreement required water first be pumped into settlement tanks to ensure it was clear before being discharged.

But on June 5, 2007, Environment Agency officers received reports of silt pollution at Milhanger Lake and Hammer Pond, and found both to be bright orange in colour.

Water sampling confirmed the lake was heavily laden with silt.

A biological survey concluded there was no impact on aquatic or plant life at Milhanger Lake, but there was "significant visual impact on the ponds".

During an interview under caution in August 2007, Paul Hoyland, project director for Balfour Beatty, explained why pumping had gone wrong and apologised.

But the court heard a second set of incidents occurred between November 22, 2007, and January 15, along the Nutcombe Valley stream. As part of construction, Balfour Beatty had cleared a large area of woodland at Tyndalls Wood in Nutcombe Valley and should have installed a drainage system to divert road run-off from entering the site.

This would have discharged downstream of the works area without contamination of the Nutcombe Valley stream.

But following a report of discolouration of some of the ponds in the Nutcombe Valley, environment officers confirmed more silt pollution, and further pollution of the Nutcombe Valley ponds was reported in December and January.

A spokesman for Balfour Beatty said: "We very much regret these incidents and swiftly introduced protective measures, including a temporary drainage system, to prevent recurrence."