LOCATION: Hangzhou, China
AREA: 198000m2
DATE OF COMPLETION: 2010
AWARDS:
10th IFLA APR Awards for Landscape Management Category: Award of Excellence, International Federation of Landscape Architects Asia Pacific Region, 2013
First prize of 2nd Landscape Planning and Design Awards, Chinese Society of Landscape Architecture, 2013

Project Statement:  
Jiang Yang Fan Eco-park is a precedent project that transformed an abandoned and dangerous silt reservoir into an urban ecological park. By adopting rational intervention strategies, landscape architects stimulated the regeneration of a natural ecosystem, enhanced its biodiversity, and established an oasis for habitats, wildlife and people. In addition to providing distinctive natural environment and unique aesthetic experience, Jiang Yang Fan has become a natural education center of Hangzhou City, promoting the sustainable idea in the public.

Project Narrative:
Site and Context
The project is located in Hangzhou, a city which is proud of its World Heritage, the beautiful West Lake and many historic sites around the lake area. The site area of the park is 19.8 hectares, nestling in a valley between West Lake and Qiantang River. Its past ten years’ history vividly shows how natural self-healing process goes on after the human intervention.
To solve the problem of siltation in West Lake, city authorities conducted a significant dredging project in 1999, and the valley of Jiang Yang Fan was dammed and utilized as a silt reservoir. More than 20 meters in depth, this dangerous reservoir was fenced against people for ten years. However, thanks to the favorable microclimatic conditions, this secluded place changed gradually and greatly – soil particles deposited at the bottom, a lake emerged in the upper layer; the seeds in silt were quickly germinating and growing while water drained away continuously; a lush woodlands swamp formed and the lake shrunk into a small pond. Without any human disturbance, this site became the habitat for many insects, birds and small mammals.
The miracle creation of nature captured people's attention and interest, so the local government decided to build an ecological park and a museum on this site.

Challenges
There was almost no ecological park in real sense in China before, neither a park on the surface of a silt reservoir.
The major constraints were associated with the site. Most of the site surface seemed dry, but below the tree roots was dangerous silt. The vegetation here seemed thriving, but the arbor species were monotonous and were mostly Salix. The trees were very dense in most places, even more than a dozen in one square meter, but all were slender and unhealthy. The woods were so dark that the understory plants were difficult to grow. The rancid smell from the moist black soil and astonishing swarms of mosquitoes brought great distress to no matter who came here. The existing vegetation, habitat and wildlife were complicated integrated, any intervention might break the existing balance and lead to unexpected result. The water content of soil was up to 246%, and its bearing capacity was less than 30 KPa. Building a park on such soft ground might be faced with complex engineering problems and safety issues. The silt was alkaline and of poor aeration, not suitable for many plant species.
This type of project was unprecedented in China, and as such, the design had to be especially innovative and creative in management of natural system, construction of landscape elements, and consideration of future maintenance and operation.

Design Strategies
Inspired by the succession processes and the regeneration capability of nature that the site revealed, our design applied rational intervention to the original ecological system and tried to stimulate the beauty of nature itself. Our position has always been trying to respect the character of Jiang Yang Fan itself and not to destroy the very properties that made it such a magical phenomenon in the first place, and then trying to present them to people in a proper way.
1 Natural system
A five-step in-situ approach was established to gradually unravel the loveliness of the site from the wild. It started with the clearance of the dead wood and some detrimental sprawling vines. After that, some areas of well-growing plant communities are preserved as Habitat Islands and fenced by corten steel sheeting to kept as living samples of the site’s natural succession. These islands will not be interfered within the phase of construction and future maintenance and will continuously provide an undisturbed environment for small animals. The existing pond and the aquatic plants nearby are also preserved. Then, for the rest area of the site, moderate thinning of the weak plants followed to promote well-growth of the woodland and provide sunlight for understory plants to grow better. Subtle landform adjustment was applied next for rainwater collection and discharged into the shallow swamp zones. In this way, some parts of the site could be free of rain soaking and some wetlands are created. Finally, understory plants with certain ornamental and ecological value, such as food resources plants for animals, host plants for insects and some nectar plants, were introduced to proper places. Thus, the regenerated plant communities could make the landscape more attractive, and provide a favorable habitat for small mammals, insects and birds.

2 Visiting System
A 1.2km-long meandering and fluctuating pontoon boardwalk punctuated with polymorphous green pergolas, long benches and punched guardrails, not only brings visitors rich visual experience, but also offers a series of observation desks and rest areas. Roads and amenities are positioned at the foothills, where the silt is shallow so that easy to install and can be used safely. As the park is on a higher elevation than the city, viewing platforms are set on the dam and hillside in order to create visual connection with surrounding hills and the city beyond. In order to create an open-air nature museum, over 80 distinctive interpretive panels were installed on the amenities to introduce the story of the site’s creation as well as its flora and fauna to visitors. The guild system is well designed with bright color and interesting illustrations.

Implementation
In fact, the construction process was more complex than envisaged and the whole project was like a great experiment. There were also some unanticipated surprises. For instance, by moderately thinning the over dense woods and removing the recklessly spreading vines, a wide variety of lush herbs sprouted quickly from the soil and formed luxuriant groundcover. For the introduced plant species, after six months’ adaptation period, some were eliminated because of failing to compete with native plants, some were shown to be well adapted to this environment, and some were still in observation. Through further research on local wetlands and native communities, some other plant species were introduced here. In addition, by breeding and transplanting the wild plants on the site, the destroyed vegetation during the construction process were restored.

Social Impact
Since its opening, Jiang Yang Fan Eco-park has received wide praise and acclaim and has been loved by local residents, tourists and design critics. Just as originally expected, the park also attracted a variety of small animals and insects. Many butterflies, bees, dragonflies, birds, squirrels, hedgehogs and frogs can be seen in Habitat Islands, woods, tussock and ponds. According to local nature-lovers’ observations, there are at least 45 species of birds and 56 species of butterflies in the park.
Today, Jiang Yang Fan Eco-park has become a recreational place for people to appreciate nature and an outdoor classroom for children, as well as a base for nature observers. Relying on the park's unique natural character, rich natural resources and integrated public education system, Jiang Yang Fan Eco-park has carried out numerous public education activities such as plant recognition, birds, butterflies and fireflies observation with the events such as tents festival, wildflower festival and eco-running festival. It has now become a well-known natural education center in Hangzhou, especially welcomed by families with children. It reclaimed an abandoned and dangerous silt reservoir into an urban ecological park in true sense.