THE CRYSTAL @ RAFFLES CITY CHONGQING

The Raffles City Chongqing mixed-use development sits at the estuary of the famed Yangtze and Jialing Rivers on Chongqing’s historic Chaotianmen Plaza. As the most historically significant site in the city, the project’s design responds directly to its geographical and historical context as well as to its importance as a civic hub. The landscape design builds off Moshe Safdie’s masterful design and features a fully landscaped podium seemingly sculpted from the deep riverbanks, with a multitude of both private garden and civic spaces, offering landscape amenities such as lush gardens, al fresco dining, lookouts, interactive fountains, playgrounds, public art and outdoor infinity pools.

Perched high above the site’s public park sits “The Crystal”, the project’s iconic “green jewel” and the largest indoor sky garden in the world. The Crystal is divided into three operating zones: InterContinental’s Hotel and Dining facilities, the Club Pool, and National Geographic’s Observation Deck. WAA’s team procured each of The Crystal’s 120+ mature trees to respond to the unique function – and micro-climate - of each space: clean, odorless, light-filtering Ilex Rotunda for the hotel lobby and its restaurants; tall, permeable Terminalia and Jacaranda to emphasize the spectacular Chongqing skyline and mountain view from the Observation Deck; and a lush selection of semi-tropical palms, ferns and Ficuses for the Club Pool, inspired by Chongqing’s famous hot springs. The planting character of The Crystal was designed to celebrate Chongqing’s rich natural environment, using plants sourced from elsewhere that would thrive within its climate-regulated interior.

The realization of this challenging endeavor was a finely coordinated effort between all design, engineering and contractor teams. One of the biggest challenges was in establishing an interior microclimate that would strike a balance between human-comfort and conditions in which tropical trees would thrive. Solutions included the use of “Low-E” façade glazing, retractable shade sails and cleverly integrated grow lights that would be turned on after operating hours to supplement light during Chongqing’s lengthy overcast periods. Ventilation systems were located on the floor, away from planting beds and tree canopies, to assure that that the foliage was not shocked by the blasts of hot or cold air. An automatic, sensory-driven irrigation system was designed to supply water to the plants when they most need it.

Plants were procured from across southern China’s subtropical provinces then placed within a local shelter for 12 months, allowing them to acclimate to indoor growing conditions as well as Chongqing’s severely overcast climate. When ready to be transplanted, each of the project’s 120 trees were carefully hoisted from the street to the Crystal’s outdoor balcony and taxied to their (generously sized) planting pit within the interior. The team painstakingly mapped the transit route of each tree – some of which exceeded 10m in length – and indoor clearances were sized appropriately to assure the trees could be successfully transplanted with their intended size and shape.

An innovative tree-replacement strategy was implemented by planting additional mature trees in what were called “on-site nurseries” - small patches of mixed species integrated into the design of each zone, to be used as future replacements for notable specimens. These “nurseries” would be replenished with smaller trees, hoisted through the structure’s hull from the podium park 250m below, ensuring that the lifecycle – and legacy - of this suspended Conservatory endures.