Site visit: Brockholes wetlands visitor centre

The new centre will sit in the lake in the nature reserve

The first oak timber frame is up

There will be glazing at the top of the roof

The classroom frame takes shape

One of the steel pile anchors

Architect Adam Khan surveys his work in progress

Each of the five rooms is about 2,000 sq ft

Water will re-flood the site to about this level

Concrete walls mark the drawbridge position

CGI of the conference room

CGI of the cafe

CGI view from across the lake

The visitor centre will be made up of five barn-like buildings of roughly 2,000 sq ft each with largely glazed walls and wooden roofs made from oak shakes – split wooden tiles with rough edges, unlike a sawn shingle which has a sharp edge

The shakes will be made from the stumps of old oak trees. Two pieces of the wood will be used to make a pillow stuffed with insulation to make the building as energy-efficient as possible

The centre will float on a 4,000 tonne, 20,000 sq ft pontoon made of recycled concrete – believed to be the first design of its kind in the country – sitting in around 2.5ft of water, with only eight inches of the pontoon visible above the water

Four steel piles, one on each side, were cast into the bed of the drained lake and will act as anchors, allowing the pontoon to rise and fall with the water level but no lateral movement

Polystyrene blocks within the pontoon will act as buoyancy aids and stabilisers in the event of any cracks appearing in the concrete and water ingress occurring

Architect Adam Khan won an international competition to design the visitor centre. The engineers are Price & Myers and Max Fordham, and contractors Mansel and Balfour Beatty.

Seeing the first building frames go up Khan said: "It's fantastic. Computer aided design these days is so good there tend not to be any nasty surprises but seeing it for real is always special."

Khan added: "The design has hardly changed since the first competition sketch. We wanted a cluster of buildings to reduce the scale in such a sensitive site and something that floated at the level of the reeds, only the roofs will be visible, hopefully it will blend in and become part of the natural landscape

Visitors to the free centre, outside Preston and within earshot of the M6, will access the pontoon via a drawbridge between the shop and classroom

Brockholes is a former quarry which flooded and became an important stop-off for migrating birds on their way to and from Scandinavia – especially the whimbrel – who spot it when they follow the Ribble Estuary in from the Irish Sea

There are over 50 breeding species of bird and 100 wintering species recorded on site each year at Brockholes

The first building seen going up is the shop and reception. The second is the classroom run by the Lancashire Environmental Fund. The three other rooms will be a café, conference space and an exhibition gallery.

Outdoor spaces will be used for breakout space for the conference and classroom and an apple orchard will be planted outside the café to provide shade from the sun for customers.

Khan said the idea behind the design was to create structures that blended into the natural surroundings. The reeds will rise to three metres, covering.

The site was acquired by Lancashire Wildlife Trust four years ago and the £8.6m project won funding from the North West Development Agency and the Forestry Commission.

The lake was drained for construction of the visitor centre and water will begin to be let back in the New Year. The centre is scheduled to open next spring.