• European Green Cities/Site Development

"Seatree" -- a new city habitat for flora and fauna

Highlight: The motivation of Sea Tree actually come from the fact that: Urbanisation and climate change put a lot of pressure on available space for nature in city centres. New initiatives for adding extra park zones to a city are rare. Yet these kind of additional habitats for birds, bees, bats and other small animals could bring a lot of positive green effects to the environment of a city.

Problem description

- Oil drilling industry brings in environmental problems

From 1950s onwards, oil has become the world’s most important source of world energy. It’s regarded as the lifeblood for the industry. Its products underpin the modern society, mainly supplying energy to machine, heat to households, and oil’s refined products constitute most of the utility of human life (e.g. chemical fiber, plastic…). However, even though we are enjoying plenty of benefits brought by oil, this industry is known to bring in severe environmental problems, knowingly and unintentionally. For example, oil drilling, oil waste dumping, oil spills wreak havoc on the environment and the animal’s habitat, physically and chemically.

Sea tree —— A Dutch innovated concept that designed for flora and fauna.

The concept of Sea Tree was developed by a Dutch architect company called Water Studio. The inspiration comes from the abandoned oil rigs. The idea of the designer Koen is, instead of getting rid of oil rig, it can be reconstructed and serves as the habitats for flora and fauna.

Inspiration - The Sea Tree is built in offshore area, similar to oil rigs

The Sea Tree is built by offshore technology similar to the oil rig which can be found in open seas (as shown in the cover picture). The original idea is that large oil companies will donate such an oil rig and redesign into a sea tree to a city showing their concern for a better environment. Desired location for sea tree can be on any surface water such as rivers, seas, lakes and even harbours (Fig. 1 & 2). The height and depth of Sea Tree can be adjusted depending on the location. The sea tree moves a bit along with the wind and is moored to the sea bed with a cable system. Under water the sea tree provides a habitat for marine species (Fig. 3) and if the climate allows, it is possible to install artificial coral reefs. The beauty of the design is that it provides a solution to waste disposal of oil rigs and it does not occupy expensive space in urban areas. The effective perimeter that Sea Tree can provide positive impact in regard to biodiversity can be up to a few miles. This will be the first floating object that is 100% built and designed for flora and fauna in the world.

Motivation - Sea Tree provides more urban green spaces

The motivation of Sea Tree actually come from the fact that: Urbanisation and climate change put a lot of pressure on available space for nature in city centres. New initiatives for adding extra park zones to a city are rare. Yet these kind of additional habitats for birds, bees, bats and other small animals could bring a lot of positive green effects to the environment of a city.

Figure 1. The Sea Tree can be habitat for many animals

Figure 2. The locations where Sea Tree can be installed

Therefore, Sea Tree is designed as a high-density green spot in a city. It is a floating structure that consists many layers of plantations which create suitable habitats for the local flora and fauna. This structure is not accessible by man. It is a semi-submersible structure, and the floating base in the bottom provides buoyancy support the upper building (Fig. 4). The grid elements of the main structure are designed for the plants to grow inside.

Figure 3. The foundation of Sea Tree can also be served as habitat for marine creatures.

Figure 4. the Sea tree structure (left), plants in the grid (right)

Reliability – Dutch knowledge on floating structure

Dutch has the heritage with hundreds of years experiences fighting against the water, the history has inspired people to develop innovative floating solutions. Sea Tree uses existing technology and infrastructure inspired from oil companies. When the oil rigs have come to the end of its lifecycle the designer gives them a new shape, function and nevertheless a new meaning.

For creating a better flora and fauna environment, Dutch designers are supported by best institutes and universities in The Netherlands which are able to provide them with the concepts to use these structures as a catalyst for the growth of flora and fauna habitats.

The cost for the shown Sea Tree design is estimated at 1 million Euro, depending on water depth, mooring facilities and transport from construction site of the desired location. Further cost differences depend on the preferred flora and fauna.

Sea Tree application: Kubuqi eco-floating island project

The concept and application of Sea Tree is flexible and can be tailored under different situations. One case for Sea Tree application is the “Kubuqi eco-floating island project” in Hangjinqi, Inner Mongolia, China. Elion Resource Group, which is a pioneer environmental restoration enterprise in China, purchased the concept from Nautilus Eco – Solutions B.V and Water Studio, and first realize the project from an excellent idea to a fabulous tangible architecture.

The contractor – Nautilus Eco-Solutions B.V

Nautilus Eco-Solutions B.V has bought the intellectual property of “Spiral Tree and energy floating island (as it is explained in the following part)”, as an adaptive Sea Tree in specific situation, from Water Studio. They contracted the “Kubuqi eco-floating island project” as a technology exporter. Nautilus Eco-solutions B.V is expert in ecological restoration and on shore embankment. They have accumulated more than 20 years’ experience in eco-material researching and producing. They own the pattern of Aqua-Flora ® products, which is made from coconut fiber that allows plant to grow above, with the roots fixed in it and uptake the nutrients from the water. Based on their Aqua-Flora ® products, Nautilus is able to build Aqua-Flora ® Island. And one case of the Aqua-Flora ® High resistance Floats was built in Maldives, together with Water Studio. The products and technology of Nautilus has been applied within the Netherlands and outside, for example, Germany, Belgium etc. They possess sophisticated technology and great reputation in eco-restoration area. Their business field ranges from gabion to floating island designing, constructing and maintenance.

The adapted Sea Tree – Spiral Tree and energy floating island

- The spiral tree

Together with Water Studio, Nautilus Eco-Solutions initiates “Spiral tree and energy floating island” (Fig.5) concept in Dadaotu Lake, Kubuqi desert, China, under the request of Elion Resources Group. “Spiral tree” (Fig.5, left) here, is a floating structure that holds three levels of green plantations. The high-density green area design aims to offer a habitat in hierarchical levels for different species. In this project, the whole design intergrades the philosophy of “the belt and road initiative”. The belt shape passage and a spiral shape represent the top-down strategy layout and the influence from the inside out, which symbolize the long-term governmental strategy in an artistic way.

Figure 5. Kubuqi Eco-floating island rendering: The Spiral Tree (left), the energy floating island (right)

Similar to the original “Sea Tree” design, the bottom of “Spiral tree” in Kubuqi is a hollow floating structure (floating ponton), which provides upward buoyancy to the whole structure. The upper three-story structure stands above the surface of the water, and the underwater part consists of a floating structure (bottom) and a transition layer (first floor) that provide buoyancy and transition zone from the water to the land. In practical applications, the hollow floating base is connected to the steel column, the steel column is deeply inserted into the lakebed. The connection between floating base and steel column is a live buckle, to ensure that the floating island is displaced only in the vertical direction.

- The energy floating island

The energy floating island is placed next to the Sea Tree, it contains large area of hydrophytes (Fig.5, right), which can up-take the nutrient from the water, moreover, microorganisms will aggregate around the roots and decompose the organic matter. Hence, the energy floating island can purify the water in a natural way. This floating island generates energy from the solar panels that supports lighting and irrigation of the plants on Sea Tree.

Sustainability – environmentally friendly material and prolonged life span

Regarding the eco-sustainability performance, the building materials are bio-degradable, recyclable, and most likely sourced from locally available material. Regularly, the product has a lifespan of 50 years with minimum maintenance.

Nevertheless, the material, and plants of the sea tree are flexible and open, depends on local availability and particular climate. For example, the initial constructing material for sea tree is composite, which is a novel light weight material, bio-degradable and sustainable. However, Corten Steel, which is a self-rusted steel is particularly chosen for this project, due to the limited working hour and local accessibility. Corten steel is widely used in landscape projects nowadays, it’s considered to be sustainable since environmental problems associated with Volatile Organic Compound (VOC) emissions from paint coatings and the disposal of blast cleaning debris from future maintenance work, are avoided.

However, in either way, the principles behind every solution are always sustainability, durability and aesthetic.

The functional highlights of Sea Tree

There are a lot of adds-on functions can be applied on Sea Tree, for example, in the water bodies where quality should be monitored, the water sensors produced by Royal Eijkelkamp (which is an environmental monitoring equipment facilities provider with high reputation in the Netherlands) can be attached. For other cities, according to different geographical features, the floating island can be designed as floating café, floating library etcetera. In this way, the unique architecture can perform its ecological functions, maximize business functions and alleviate the shortage for urban land – use problems. On the top of that, the significance also lies in the educational value to the citizens. As it’s a sign that shows appreciation and value on nature from human beings, it performs as an example to think along with ecosystems.

In the same time, commercial value for the surrounding area can be boosted, creating more potential selling points for especially real estate developers.

©2020 by European Green City Development Foundation