Jiaxing City Concept – “Nine Rivers for One Heart”
client Jiaxing Municipal People's Government
The Beijing-Hangzhou Canal flows slowly, giving birth to a peaceful and soft Jiangnan water village.
For Jiaxing, which lives and thrives on water, the river and the city are now isolated and separated. Changxian River, Pinghu River and Jiashan River represent the life and cultural waterways of Jiaxing. Challenges such as ecological restoration, urban re-activation and cultural identity hinder the full potential of Jianxing. The river system is like a spider web weaving through urban areas. The “Nine Waters to Heart” project offers new opportunities for the future of this Jiangnan water city.
An important design principle for the city’s waterway network is to maintain the flow capacity and water circulation in the system. The Jiaxing City Flood Control Project and associated works have been carefully planned and designed to ensure that they will minimise blockage and maintain water circulation in the city.
The designs for each of the main waterways can complement this strategy by maintaining the cross-sectional area of the waterway, and avoiding placing structures or planting where they would impede flows. Three general design options are illustrated on the left, to suit different scenarios.
Aquatic habitat will be reintroduced by creating more diversity in the waterway and aquatic landscape, for example:
• Creating a diversity of bank profiles, including banks with different vegetation types
• Creating a diversity of water depths
• Introducing wetland vegetation into shallow water
• Using a diversity of bed and bank materials and textures
The rock benching could intercept runoff from the local catchment, treating local runoff before it enters the main waterway. A pumped system could recirculate flows from the waterway through the wetland, which would also serve to reduce residence times and aerate the water during times of low flow in the waterway (ie. Aerated wetland filters).
These provide a unique opportunity to provide wetland filter cleaning within the existing canal profile in areas where banks cannot be cut into adjacent parks/open space areas.
The bench wetlands would need to be fed with pumped water from the river and recirculated back into the river system, creating waterfall cascade features for each bench wetland. We have proposed concrete culverts as the structure to allow the river water volume to remain untouched.
In comparison to floating wetlands, the bench wetlands have important soil/plant rhizome & biofilm components, significantly enhancing the biological processing of organic material and nutrients.
Vertical Water Gardens
Green in pockets along the walls will add tremendous aesthetic and ecological value to the river’s walls lining the canal.
Recycled Water River Pool
For areas where water quality is not sufficient for swimming at present, there is opportunity as indicated on the Changqian River masterplan to implement a recycled river pool as a separate structure within the riverscape.
Gentle Meander into River Alignment
The meander is the pulse of the river and the movements caused by flowing under the influence of gravity, through the slightest resistance, generate curving vertical forms.
Timber Flume Drain
A timber flume drain will assist in directing the faster water flow to the east, whilst maintaining slower water in the minor channel. The slower flow will assist in water cleaning , especially focussed within the aerating wetland system and naturally occurring wetland filter edges.
Shifting of River Banks
Where possible, creating more organically curved shapes of the edges of the Phoenix Island will also assist in water flow and circulation.
New Connecting Channels
Within the Jiashan and Pinghu Rivers, the masterplan proposes new estuary channels to improve water circulation and health of the waterways
Wetland Loop Channel
The wetland area required to treat a large waterbody in a recirculating system can be estimated approximately based on the volume of the water body. Based on the typical channel sections, the waterway cross-sectional area has been estimated for each channel. The waterway volume and wetland treatment area have then been estimated accordingly. This provides a basic indication of the wetland area required to treat the water volume in the channel.
- Client - Jiaxing Municipal People's Government
- Date Completed - 2020
- Expertise - MASTERPLAN, LANDSCAPE ARCHITECTURE; ARCHITECTURE; URBAN DESIGN, CITY PLANNING; WATER SENSITIVE DESIGN - Consultant: Hanjia Group Co Ltd