The over-140-year coal mining activities have left large-scale areas of subsidence, including 30 km² in the Nanhu Lake area. Nanhu Lake is situated 1 km south of city center, and the mined-out areas there subsided in the earthquake in 1976. Later on, Nanhu Lake became a rubbish and industrial waste landfill and a dumping ground for domestic sewage, a typical urban brownfield. In 2008, ZEHO ECO began the ecological restoration work for the Nanhu Lake Central Park. We completed the construction of the park and opened it to the public in April 2009. By scientifically restoring the ecosystem, we dug out and reused 8 million m³ of garbage, 8 million m³ of fly ash and 4.5 million m³ of coal gangue. Tangshan was awarded the hosting right of the 2016 International Horticultural Exposition in 2010 and selected the Nanhu Lake Central Park as the exposition site. ZEHO ECO started the overall design and core area construction work in 2013.

The first tremendous transformation of Nanhu Lake turned it from an urban brownfield into a central park. The 6.3 km²-park is an urban public space featuring ecological restoration. Based on the overall analysis and deep research on the site, the project incorporated ecosystem, historical culture and modern civilization while preserving, restoring and rebuilding original garden elements (mountains, water bodies and wetlands) to embed them into the man-made environment, creating a safe, open, comfortable and ecologically valued artificial ecosystem.

The second transformation took it from a central park to the International Horticultural Exposition. The year of 2016 marked the 40th anniversary of Tangshan responding to the earthquake. Hosting the event in the Nanhu Lake Park, where 133 sceneries were presented occupying no farmland, has shown the results of ecological restoration and the green development path of prioritizing ecology, protection and husbanding, as well as increasing popularity of the park. It has also shown Tangshan people’s determination to protect environment, restore ecosystem, transition from an industrial city to a resource city and pursue sustainable development.

Long Mountain (Fly ash mountain) ecological restoration

Under the guidance of ecosystem restoration theory, we constructed the Long Mountain and converted the fly ash mountain by bringing geotechnical engineering and ecological engineering together. By ensuring the stability and safety of the fly ash mountain while building a multi-tier ecosystem out of existing and deserted resources, we established a healthy, stable and sustainable ecological internal circulation mode. We moved from simply improving environment to pursuing sustainable development, adding more ecological value to the Long Mountain after it was remediated and making it an artificial mountain ecosystem which benefits the transformation of regional eco-safety landscape.

Landfill treatment

Based on the ecological safety evaluation of the landfill and professional solutions targeting existing problems, we applied technologies of low interference, low cost and low energy consumption to convert the 50-meter landfill in a closed environment, emitting no pollutant during the treatment. Meanwhile, we also combined the ecological restoration of the landfill and garden design by presenting the recycling process artistically, showing how the landfill had been treated.

On July 28th, 2016, President Xi Jinping visited the site and pointed out “The 2016 Tangshan International Horticultural Exposition is an excellent piece of work to show the world what Tangshan has achieved”. In 2020, the project was listed in Cases of Ecological Product Value Realization launched by the Ministry of Natural Resources of the People’s Republic of China. The ecological restoration of Tangshan Nanhu Lake Subsided Land has been well received globally. Regarding ecological restoration and environment protection, it won the UN-Habitat Scroll of Honor Award and was also awarded the Planning Environmental Golden Awards of National Classic Residential Building Planning and Design Scheme Competition.

We restored the area damaged by industry to its natural glamour, supplying more high-quality ecological products. The previous subsided areas and deserted mining sites have become “Green Lungs” and “Anion Air Purifier” of the city center. 65% of the area is now green space, growing a lush vegetation of over 220 species. The 11.5-km² water area is a natural habitat for over 100 types of birds to dwell in. After ecological restoration and overall treatment, we now see a better climate in the Nanhu Lake Park, a more livable city, a more beautiful environment and more stable supply of ecological products.

We believe that lucid waters and lush mountains are invaluable assets and strive to realize the economic values of ecological products. Following the mode of “ecology + industry”, we actively planned out cultural, tourism and sports industries in the Nanhu Lake area, giving an impetus to integrating the lake and industries and the lake and the city, and promoting ecological industrialization. In 2019, over 7 million tourists visited Nanhu Lake, creating a continuous growth of both tourist numbers and tourism revenue. The gradual improvement of environment and facilities elevated land price of its surrounding areas by nearly 100 billion yuan, attracted more people, resources, investment and information, created a new growth engine in regional development and gained a spillover effect of ecological product value.

We brought benefits to people and highlighted the social value of ecological products. With the fine ecological environment and livable environment, the Nanhu Lake Park has become a leisure place for people to enjoy life, achieving collaboration, participation and common interests in ecological construction. In addition, the development of ecological industries has effectively increased employment and income, boosted the interactive development of catering, hospitality, transportation and entertainment businesses, and revealed the social value of ecological products.