Paris-based architecture studio Vincent Callebaut Architectures has proposed a permeable floating landscape to recover natural environment of Seoul's Yeouido Han River Park between the Mapo Bridge and the Wonhyo Bridge, which aims to enhance the site's natural irrigation by transforming the park into an ecological forest of willow trees. Called Manta Ray, the creation of a marsh-like filtering strip of plants strenghthens the natural protection of the banks against river floods.

This permeable landscaping enhances the Han River's original scenery, thus restoring the park as one of the most praised tourist attractions in Seoul, as well as a new symbol of the symbiosis between urban dwellers and the natural environment. 

"The project's ambition is to turn Yeouido Park into a genuine cultural hub, where nature progressively asserts its rights over the concrete city again to better protect it. The urban plan articulates around four biomimetic-looking projects whose architecture is densely vegetalized," said Vincent Callebaut. 

Bio-inspired from the hyperbolic geometry of a Manta ray, the ferry terminal is suspended above the marina and gardens. The idea is to free the view towards the Han River and Yeouido Park by bringing all programmatic uses above the water. The architectural project is divided into three levels: panoramic floating dikes along the lower docks, panoramic floating dikes along the lower docks and observation deck towards Ban Island and rooftop orchard.

Steel dikes float on the river. Linked together with flexible seals, they surround and protect the marina from water currents. The marina is dedicated to small private and public boats such as water taxis, yachts and small sailing boats, but also to government ships. These floating piers integrate the technical equipment inside double floors, supplying boats with energy (water and electricity) and biofuels. 

In parallel with the maritime route and 60 meters (c.197 feet) away from the bank, a long straight dock can accommodate the simultaenous docking of five large cruise boats of up to 700 tons each. In the heart of the marina, a floating theatre can be used to organize outdoor shows, while amphibious gardens line up the piers. 

The docking and fixed positon of this circular floating platform are secured by a network of chains, anchoring it to the bottom of the river with 26 concrete slabs. The recycled concrete slabs are laid out to avert any structural component interference with the safety zone surrounding the metro line 5 tunnel right under the river bed. The chain-mooring system can be reinforced with a "dolphin-type mooring system" if the waves are too strong when ferries dock.

From the radial and concentric floating piers, tree-like structures made of CLT (cross laminated timber) harvested from eco-responsible Korean forests rise towards the sky. 

Woven in a honeycomb pattern, those trees branch out at the top, creating the structure of a giant Manta ray over the marina. Inside their trunk, spiral staircases, glass elevators and helical ramps provide access to service and recreational equipments located on the upper level, and to the rooftop. 

Reception and leisure areas, food courts and exhibition and educational spaces are laid out in the programmatic functional rings, freely punctuating the large double-curved open space area. This hyperbolic paraboloid rolls out like a soft-slope landscape, inviting passengers and visitors to wander and stroll while offering stunning views of the river.

To learn about the river history in a unique, attractive location; to pick fruits in a blooming orchard before taking off on a cruise; even better, to marvel at the skyline towards the "N Seoul Tower" and the Mount Bukhan hills from a balcony floating over water: these are the emotions this rooftop promises to Seoul residents. 

Its main access is via the cable-stayed pedestrian bridge that links the metro station to the park. Its principal identity comes from the skyward wind trees and solar shields that guarantee its complete energy autonomy.

In this early 21st century, Yeouido Park is conceived as an experimental urban space dedicated to sustainable development. The Government wished to make it a bridgehead for innovation, combining the best of low-tech and high-tech while promoting the rehabilitation of urban ecosystems and biodiversity.

"Seoul is finding new ways to invest in this kind of soft infrastructure, helping to foster social cohesion with a greater sense of community among diverse socio-economic groups," said Vincent Callebaut Architectures.

"With an eye toward increasing equitable access for everyone to these new facilities, this floating vessel is an example of biophilic and resilient architecture, demonstrating that it is possible to build with nature rather than against it, by respecting the life of the river and allowing the local fauna and flora to flourish." 

The "Manta Ray" project strives to be a prime example of energy saving, reduction in carbon dioxide emissions and circular economy. In order to optimize the cycle and resources, the ferry terminal embraces the three R's of waste management: Reduction in waste; Reuse of resources; and Recycling of materials. 

The honeycomb-like CLT structure is thus entirely generated from local eco-responsible forest trees, where harvested trees are systematically replaced according to nature's regeneration cycles. The materials used for interior spaces and furniture also come from biosourced, recyclable and/or recycled origin.

"The "Manta Ray" project promotes the permeability and renaturalization of river banks in cities with rivers running through them. The banks become new playgrounds for social innovation, and for urban "consumers-actors" seeking to promote urban farming, agroforestry and permaculture."

"The goal is to make them less vulnerable to climate change, and to the subsequent dramatic flood and urban heat island events witnessed over the past decades," explained Vincent Callebaut Architectures.

To solar energy, the rooftop includes 4,4550 square meters (c. 49,000 square feet) of laminated glass façade, with encased photovoltaic polycristalline cells. The roof edge is lined with 3,500 square meters (c. 37,300 square feet) of opaque photothermal panels.

To wind protection, rooftop wind trees make up a 52-VAWT (vertical axis wind turbine) farm. Biomess is provided by organic and biodegradable waste from Yeouido Park supply a biomethanation plant, providing energy for the equipments.

For water recycle, oscillating-foils hydrokinetic turbines (HAO) are integrated and synchronized along the hull of the large floating barrier encircling the marina. Biomimetically-inspired from the tail of a whale or dolphin, they move back and forth by tilting their profile, turning the river's kinetic energy into electrical energy. 

These renewable energy sources work in collaboration, enabling the four cores of the project to share  the energy their produce in real time via a smart grid.

Project facts

Type : International Competition

Host & Order Institution: Seoul Metropolitan Government

Location: Yeouido Han River Park between the Mapo Bridge and the Wonhyo Bridge

Status : Masterplan & Concept

G.F.A. Spatial Planning : 25 600 m2 = 9100 m2 Ferry Terminal & Pier Deck + 8500 m2 Yeoui Terrace + 8000 m2 Cultural Complex

All images © Vincent Callebaut Architectures

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