Project Overview

Tongjian Lake, located in Shuangpu Town of Hangzhou, is historically the sister lake to the famous West Lake. Positioned at the convergence of the Qiantang, Fuchun, and Puyang Rivers, it was a key ferry point in southern Hangzhou and a significant cultural hub during the Southern Song Dynasty. Over time, sediment from the Qiantang River and land reclamation projects caused the lake's waters to recede. This led to local water shortages, flooding problems, and a fragile ecosystem.

The design team used landscape techniques to address flood control, ecology, culture, and public needs, revitalizing Tongjian Lake's historic and scenic landscape. Led by landscape designers, the urban water hub project improved water circulation and raised water quality from Class V to Class III standards. It also met the 20-year return period standard for flood control.

The region's ecological environment has improved significantly. Biodiversity has increased, and rare species are now appearing. Tongjian Lake, once restored, has become a beloved ecological park, cultural and natural education center, and community gathering space. This rejuvenation has also supported the area's industrial growth and sparked regional development and economic revitalization.

Project Commissioner

Hangzhou Zhijiang City Construction Investment Group Co., LTD

Project Creator

Power China Huadong Engineering Corporation Limited

Team

Rui Fu, Yun Yu, Tao Zhang, Feng Chen, Binbin Wang, Xiaomin Ye, Junchao Huang, Ming Hu, Sha Li, Ying Lin, Baoliang Guo, Shuhang You, Hao Zou

Project Brief

To meet the water planning requirements of 5 million m³ total storage and 3.2 million m³ regulated storage, the design team integrated factors like historical lake morphology, site spatial pattern, landscape resources, and transportation systems.
They aimed to restore the historical 2 km2 surface area of Tongjian Lake, strategically laying out 859,700 m2 of deep water areas, 732,200 m2 of shallow water areas, and 408,100 m2 of islands. They established the shoreline's initial form and water depth, setting the regular water level at 6.5m, lakebed elevation at 2.5m, and shallow water area base at 5.5m. Leveraging the Grasshopper software in Rhino, they calculated the fractal dimension, shoreline development coefficient, and water body spatial containment area, reconstructing the 28.3 km ecological waterfront.
The team designed biomimetic island shapes, encapsulating varying lake surfaces, streams, and wetland archipelagos, fostering diverse lakeside experiences.
The design team drew upon the site's natural elements - lakes, mountains, fields, tea, and grass - to rebuild the blue-green infrastructure and restore habitats. By integrating wetlands, islands, revetments, and gentle slopes, they fostered diverse ecological communities, enhancing species biodiversity.
They also employed cultural heritage assessment methods to identify and organize existing relics, creating conservation areas. These historical memories were embedded into landscape focal points like the ancient lake port, which highlighted the site's history.
Throughout the design process, they incorporated industry development, weaving in experiences like hiking, boating, mountain climbing, camping, and cultural education, leveraging ecological water management to drive regional economic growth.

Project Innovation/Need

Through excavating Tongjian Lake and a new 1.86 km drainage tunnel, the project boosted the storage capacity by 3.2 million m3, enhancing the region's flood control from a 10-year to a 20-year recurrence.

After the lake's completion, formerly homogeneous forests of camphor and metasequoia trees have transformed into diverse plant habitats, such as Pontederia cordata + Acorus calamus + Metasequoia glyptostroboides, Lythrum salicaria + Hypericum monogynum + Sapindus saponaria, and Miscanthus sinensis + Prunus serrulate + Cinnamomum camphora mixes. Biodiversity surveys have identified some of Zhejiang's most charismatic birds like the Hydrophasianus chirurgus, Emberiza pallasi, and Emberiza yessoensis, as well as rare animals such as the Rana zhenhaiensis, Anas zonorhyncha, and Deinagkistrodon acutus.

The Tongjian Lake ecological water conservancy project has transformed the regional industrial structure and brought new life to the area. In 2022, five villages around the lake added 67 new guesthouses, 25 restaurants, and 12 cultural and creative enterprises. This has revitalized the previously declining appearance of the surrounding villages.

Tongjian Lake Park has become a beloved ecological suburban park and a new destination in Hangzhou. During weekends and holidays, the average visitor flow reaches 10,000 people/day, and recreational transportation facilities like bicycles see daily usage of over 2,000 times. Each year, Tongjian Lake Park hosts over 30 science activities, with participation from nearly 10,000 students.

Design Challenge

Sediment buildup from the Qiantang River and land reclamation caused problems for Tongjian Lake. It was encroached upon by factories, ponds, farmlands, and villages. Some areas turned into abandoned paddies and ponds for chia and water chestnut cultivation. The original 2-square-kilometer lake shrank to less than 0.2 square kilometers.

With rapid urban development, the lake's flood control capabilities lagged, leading to frequent flooding with water depths exceeding 1 meter. The lake's foundation was poor, its ecological environment fragile, and its habitats limited, dominated by camphor trees, cherry blossom nurseries, and secondary herbaceous plants. As the lake receded, historical and cultural relics were destroyed or disappeared, and nearby villages suffered economic decline.

The project's challenge was to improve flood control while enhancing water quality, ecology, landscape, and regional cultural-economic revitalization.

Sustainability

The ecological water management project of Tongjian Lake has reconnected the city, nature, and its inhabitants. This initiative enhances the flood control function of the lake, raising the flood prevention standard of its region to a 20-year return period.

The water quality in the region and the central lake area has been significantly improved. The establishment of terrestrial and aquatic plant communities in the lake area is refined, significantly improving the ecological environment and substantially raising the biodiversity index. The latest survey revealed the addition of 10 bird species, including nationally protected species such as Hydrophasianus chirurgus and Fulica atra.

The project has spurred sustainable development in the region. It mobilized 250 million yuan in private investments and provided jobs for over 800 people. Additionally, it attracted 300 local talents to return to their hometown and secured investment agreements totaling 5 billion yuan. Furthermore, Tongjian Lake Park has hosted numerous large-scale events like walking tours, marathons, and cultural performances. Local residents have formed running clubs, and the park has organized over a hundred running and walking activities.

Tongjian Lake once vanished, but it has now re-emerged as a renowned lake. It has become a sought-after destination for various activities like embracing nature, experiencing culture, camping, and gathering. The Ecological Water Conservancy Project at Tongjian Lake exemplifies landscape design, demonstrating a harmonious balance in hydrology, ecology, economy, culture, and public interest.

Landscape Design - International - Public

This award celebrates creativity and innovation in the use of practical, aesthetic, horticultural, and environmentally sustainability components, taking into account climate, site and orientation, site drainage and irrigation, human and vehicular access, furnishings and lighting.
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