'Building in a zoo is really different'

Builders proud of final result new Lions residence

A new Lion enclosure has recently been under construction at ARTIS. The new enclosure is ten times larger than the old one and features a hilly landscape with the appearance of a savannah in different seasons.

Construction contractor Van Wijnen Haarlemmermeer, installer A. de Jong and De Enk Groen en Golf worked closely together on this unique project. De Enk had previously worked for the Amsterdam Zoo and is therefore familiar with the way of working at such a specific location. Bart Los is project manager of De Enk Groen en Golf and, as main contractor, has a coordinating role in the project. "On this spot in ARTIS previously sat the Algazelle enclosure. The old Lion enclosure was too small and ARTIS has been working for years to renew the park, with fewer species and larger and more modern enclosures. This area was already 'savanna area' for elephants, zebras and giraffes, among others, so it made sense to build the Lion House here as well." 

Two issues had priority during the construction of the project, says Jeffrey van Dalfzen of Van Wijnen: "Safety and logistics and thus the prevention of disruption to visitors. For example, most of the transport of large elements took place by water and we often worked outside opening hours. Then, however, the construction site was easily accessible to cars." From the early stages, the three parties thought about the best way to execute the project and the project was approached "smartly.

Retain existing waterfall

The first step was to demolish the old buildings and level the terrain. Only the algae's indoor enclosure and the waterfall remained. Next came new fences and installations. The waterfall is the eye-catcher of the enclosure and a visitor tunnel runs between them. Los: "It was a hard requirement to leave the existing waterfall in place. This presented quite a challenge in terms of execution. In the end, the base was realized according to plan, only slightly smaller than the architect had anticipated."

Installer A. de Jong took care of the installations, both inside and outside. Project leader Jan Berendsen: "We realized the piping for the waterfall. In addition, the lions were given a number of heated rocks and we placed one in the visitor area, so that visitors get an idea of what the lion experiences. We also installed a sound system, which the animal keepers use to provide a daily educational program for visitors. Because this is an animal enclosure, we built in some extra safeguards. For example, in addition to the thermostat cable for the heated rocks, we installed an extra empty pipe. This can be used in the future for a new thermostat cable, for example. Also, the pipes are installed extra deep in the ground."

The foundations of the enclosure are 80 cm deep to prevent the lions from digging underneath. For the roof garden in the enclosure, a concrete mesh mat was placed on the substructure. Van Dalfzen: "In connection with the risk of biting through, ARTIS gradually chose thicker mesh. It is not woven mesh, but consists of clamps. Should this netting nevertheless become damaged, a hole in the fence is not created immediately." The safety of the enclosure for both animals and humans was continuously tested during construction by a visitation committee and by animal care. The new Lion enclosure was officially opened in early October. 

Challenges

The project had some challenges. For example, the attachment of the water fencing to the sheet piling is below the water level. This required pumping out water and the welding work took place from a barge. In addition, the indoor enclosure houses a new operating room for ARTIS' veterinary staff, which again had to meet specific requirements. The three gentlemen are very satisfied with the cooperation with each other, with the subcontractors and with ARTIS. "We had to switch gears every day. By keeping a good look ahead, it worked out well. Working in a zoo is somewhat different from building a new building."