Project Description

The sunken observatory is built right on the edge of the stunning new Flamingo Lagoon at WWT Slimbridge Wetland Centre. The observatory, which is proving a great success with visitors, allows them to stand below the water’s surface, giving them a unique view looking across the lagoon, through the legs of the flock of around 250 Greater Flamingos.

The new habitat, which the flamingos share with a variety of African duck species, is representative of an African wetland, with special islands for the flamingos to nest and which will encourage them to breed.

WWT Slimbridge is one of nine wetland visitor centres run by the Wildfowl & Wetlands Trust (WWT) throughout the UK. WWT works in the UK and around the world to conserve wetlands and its wildlife and by offering the chance to experience nature up close at one of its wetland centres, gives people a better understanding of the value of wetlands to us all.

Studying the resident population of Greater Flamingos at Slimbridge provides vital knowledge for scientists and local people to help protect the species in the wild, such as the establishment of new breeding sites.


Project Requirements

With the observatory being sunk below the water level, and with water lapping against the concrete structure, it was essential that water could not penetrate either through the concrete itself or through the joints between the floor slab and retaining walls.


Sika Solution

The Sika® Watertight Concrete System was used in the construction of the observatory. Hanson Concrete supplied 70m3 of Sika® Watertight Concrete to the project. Watertightness of the concrete was obtained by incorporating two powerful, state-of-the-art, Sika admixtures in the mix. Joints were sealed using the SikaSwell® jointing system, which consists of joint sealing profiles that expand on contact with water. Use of the Sika® Watertight Concrete System, which has a successful track record going back 50 years, has ensured a dry, comfortable viewing area.