Citadel Client: ONW/BNG Architect: Koen Olthuis - Waterstudio.NL Start Construction: March 2011 Location: Project The New Water, city of Westland, The Netherlands Project: Floating apartment building – 60 units Depth: 9 feet Height: 40 feet Platform: 240 x 420 feet
Project Description The Dutch and water have always been in a love & hate relationship. Fighting the water in the country but also using the sea’s infrastructure for international trade. In Holland in the city of Westland, Waterstudio is designing now a project that is contributing on a new relationship with the water. Not one of living next to the water but living on water. The Citadel is Europe’s first floating apartment building. Citadel means fortress for protecting a town. It’s walls are designed to be the last line of defense when “the enemy” breach the other components of the fortification system.
Depolderising Holland has as many as 3500 polders which are below sea level and kept dry by pumping water out 24/7. The citadel is part of an urban development with 1200 houses that will be built in a depolderised zone, called the New Water . The new water is a polder that will be deliberately filled with water after a few centuries artificially dry period. The depolderising done to protect other surrounding polders for flood during times of heavy rainfall. The only way to make such a project financial feasible is buying out the existing houses and building and selling new houses adapted to water fluctuations. DesignThe toolbox of floating developments in Holland is still not so large, floating houses, villas are normal, but concepts with high density are not available. The Citadel consists of 60 units which makes it the first floating development with more than 30 housing units/acre water. This relatively high density leaves more open water surrounding the building. The floating building is a composition of 180 modular elements around a courtyard on top of a floating concrete caisson foundation. All the apartments have waterview and most of them have a berthing place for a small boat. The Citadel will be projected on the middle of the water with a floating road for connection with the shore. Fire trucks, ambulances and inhabitants can drive up to, or even in the building. Comfort The comfort level for this development is the same as in for instance a high rise building. You will not feel any movement. This is because of the dimensions. The building is made of lightweight construction but special care is been given to the lowest possible noise level. The same standards as used for normal land base dwelling. The floating foundation is a large and heavy concrete caisson that will house the Citadels car park. Common technology but custom engineered for the dimensions of approximately 240 x 420 feet and 9 feet high with 1 feet thick walls. Construction of the building will be done in a temporary dry dock on location. The actual depth of the water after depolderizing would be 6 feet while 12 feet of depth is needed. For that the construction site will be digged out which will create space for the 9 feet of depth of the floating construction. When the building is completed the pumps will stop and the site will flood. While being flooded the building will start to float. Sustainability Sustainability is a focus point for the principal of the development. The Citadel has as first floating apartment building the possibility to be a benchmark for floating urban development. The apartment building is surrounded by greenhouses, the interaction between the energy management of the greenhouses and the project is under investigation. Also water cooling by the exchange of heat by pumping water through the building floors is an option. The facade of the building is from aluminium panels. Those cost a bit more energy to produce but they have a very long lifespan and less maintenance on this water location. The energy consumption over the total lifespan will be 25% less than a conventional building on land. With more than 50 roof terraces this project is a challenge for green roof designers to come up with lightweight green roofs that add to the climate control of the building. Top end project In the new water a mix of archetypes with different prizes are being developed. Being a semi-governmental development project is serves a social economical an ecological purposes. The citadel is at the high end of the range of prizes this means that buyers for the citadel are high demanding. This is answered by an architecture in which each unit has a different floor plan and outside space. The maisonettes in the apartment building open the possibility for a rich variety of double layered outdoor spaces. The construction of the houses is engineered in such a way every client can design his own personal floor plan within the determined shapes. Future The citadel project is the first of 6 floating apartment buildings in the New Water project. When finished this project will be a reference project for floating developments in waterfront cities worldwide. It is not the architecture but the sustainability, technology and density that opens new possibilities for developing beyond the waterfront