Bat-flap allows bats access to disused tunnels

10/03/2009 17:00:29 Southern Water installs bat-flap in disused borehole tunnels

March 2009. We're all familiar with the cat-flap. Now for the water industry there's the bat-flap, following a bit of lateral thinking by Southern Water and leading secure access provider, Technocover.

Southern Water came up with the unusual adaptation in replacing doors to two hillside tunnels leading to a disused water borebole, near Ventnor on the Isle of Wight.

Dating back to the late 1800s, the tunnels cut deep into the Great Woods hill to a well which once formed part of a spring water collection system feeding the public water supply to Shanklin. Although no longer used, the tunnels and borehole remain part of Southern Water assets, making the company responsible for their upkeep and any related health and safety issues.

Previously, Southern Water had used wooden doors to close off the tunnels and at one time they had even been bricked up. But teenagers curious to explore inside had consistently vandalised the entries, leaving security and public health and safety compromised.

David Nye, Southern Water manager for the Isle of Wight, said: "We needed to look at installing something stronger to safeguard the public and keep youngsters out, while preserving access for the purposes of structural surveys."

Security access specialist and longstanding supplier, Technocover, was called in to design and manufacture a more appropriate security solution. Technocover has been supplying Southern Water with LPCB approved high security access covers and associated equipment for almost a decade, for reservoir security upgrades and other applications. But the door also needed to take into account other factors.

David Nye said: "We suspected that bats might be using the tunnels, so we called in the island's resident bat expert to consult on how we could accommodate their needs in the design of replacement doors."

17 bat species on Isle of Wight
Founder of the Isle of Wight bat hospital with his wife, Donna, Graham Street is an expert in the seventeen bat species found on the island, which are protected by stringent UK and European laws. Graham provides consultancy to companies and individuals on the legalities and practicalities of projects that might encroach on bat habitat, for the purposes of feasibility studies and planning applications.

He has previously advised Southern Water on making provision in tunnel works elsewhere on the island to protect very rare Greater Horseshoe bats identified at the site.

Graham said: "Southern Water is very conscientious about protecting the welfare of wildlife in any work they undertake, as demonstrated by the care taken in the design and construction of Technocover's doors.

"After visiting site, I assessed that the tunnels would be an ideal hibernation or roost location for most woodland bats and advised the provision of bat access in the replacement doors."

Bats can choose unusual places to live, favouring the dark and constant temperature of underground spaces such as tunnels.

In line with Graham's advice, Technocover provided a 20mm high by 300mm wide bat aperture in the doors, complete with wooden perch to the front and rear, ensuring that there were no sharp edges that could cause injury.

Graham said: "The specification for the bat aperture followed guidelines on dimensions and materials used in the design of proprietary bat boxes, tubes and artificial roosts. The tunnels are likely to be used by species such as the Daubenton's, Natterer's, Whiskered and Brandt's bats."

Bat Hospital
Graham and Donna Street have been running a bat hospital at their Sandown home since 1996, using purpose-built aviaries in a bedroom and part of their living room to accommodate patients. Completely self-funded, the hospital can now cater for up to 100 bats at any one time, providing invaluable support to the island's bat population.