TIJ

THE MEANING OF THE WORD TIJ IS A DUTCH JOKE. “TIJ” MEANS “TIDE” WHICH REFERS TO THE RETURNING TIDES IN THE HARINGVLIET, BUT WHEN QUICKLY PRONOUNCED IT ALSO MEANS “THE EGG”.

TIJ observatory
Photography: Merijn Koelink

Tij is the biggest and most striking of a series of objects designed to celebrate the opening of the Haringvliet sluices in November 2018. The sluices were opened in order to improve water quality and biodiversity, while also stimulating fish migration from the North Sea to the river delta system of Maas and Rhine in the Netherlands.

This will create a new, salt-resistant and salt-loving natural environment. The biodiversity in the surrounding nature reserves will increase and a more robust, healthier ecosystem will develop in the coming years. To let people experience and explore these changes, a series of bird observatories have been designed in the Haringvliet area.

Master Plan
Illustration: RO&AD ARCHITECTEN

Tij is an egg-shaped bird hide situated in Scheelhoek, a nature reserve close to the Haringvliet sluice near Stellendam, Netherlands. The reserve consists of large reed beds on the inside of the coastal defences and some flat sand islands outside.

Sandwich tern
Photography: Katja Effting

These islands are breeding and feeding grounds for several species of birds like the common tern, spoonbill, and the icon of this area, the sandwich tern.

Path to the TIJ observatory
Photography: Katja Effting

Tij observatory is part of a large scale landscaping plan where people can experience the Scheelhoek nature reserve in a walk from the car parking area to the looking point. Walking along the path, visitors can view several types of bird biotope favoured by sand martins, several kind of waders and, of course, terns.

Tunnel with holes for bird nesting
Photography: Katja Effting

To prevent the birds from being disturbed, the last section of the path is actually a tunnel made of re-used mooring posts and second-hand azobe planks which were once used in the brick industry. The tunnel is covered in sand to provide habitat for terns or waders.

The outside of the tunnel provides artificial nesting holes for sand martins. The end point of the walking route is the egg-shaped bird hide from where you can view hatching terns and all the other species that live in and around the water.

South view elevation
Illustration: RO&AD ARCHITECTEN

The egg itself is modelled on a sandwich tern egg, and sits on a nest of sand, much like a tern would have done it herself. The nest of the egg consists of vertical ‘feathers’ of chestnut poles, reeds and small sand dunes. The egg itself is parametrically designed to achieve a good ratio between form, structural integrity, size of the timber, and size of the openings.

The egg itself is modelled on a sandwich tern egg
Photography: Katja Effting

The structure has been constructed as a File-to-Factory Zollinger to provide relatively big spans with small timber parts. The lower part of the egg, which floods a few times a year, is made of accoya. The upper part, which stays dry all year, is made of pine. The upper part is thatched with local reed, harvested from the inside of the sea defences.

Section
Illustration: RO&AD ARCHITECTEN

The thatched roof stops just above the highest possible water line. The floor inside the egg is a hybrid wood (CLT)- concrete floor which acts as a structural stabiliser and from where there is a beautiful view of the surrounding islands, the Haringvliet sluices and the water.

TIJ observatory interior
Photography: Katja Effting

Tij is thatched with local reed and has a timber structure which has been completely File-to-Factory produced in 402 parts and has been assembled at the site. It can be completely disassembled. Through its re-usability, its modularity, its materials and its contribution to the nature environment, it is almost completely circular and sustainable.

Reflecting the transitory nature of all things, it must also be noted that the Bird-EI is also temporary and will be taken apart at some point in the future. At that time, it may be reused or recycled without detrimental effects to nature or man.