Built on a brownfield of a former industrial site, Houtan Park is a regenerative living landscape on Shanghai's Huangpu riverfront. The park's constructed wetland, ecological flood control, reclaimed industrial structures and materials, and urban agriculture are integral components of an overall restorative design strategy to treat polluted river water and recover the degraded waterfront in a aesthetically pleasing way.
The first challenge was restoring the degraded environment. The water of Huangpu River is highly polluted with a national water quality ranking of Lower Grade V, the lowest grade on a scale of I-V. The second challenge was to improve flood control. A conventional retaining wall would continue to limit accessibility and preclude habitat creation along the water's edge, so an alternative flood control design proposal was necessary.
A linear constructed wetland was designed to create a reinvigorated waterfront as a living machine to treat contaminated water from the Huangpu River. Cascades and terraces are used to oxygenate the nutrient rich water, remove and retain nutrients and reduce suspended sediments while creating pleasant water features. 2,400 cubic meters per day of water can be treated from Lower Grade V to Grade III.
The wetland also acts as a floodable buffer. The terrace design of the wetland alleviates the elevation difference between the city the river, safely reconnecting people to the water's edge. Crops and wetland plants were selected to create an urban farm allowing people to witness seasonal changes. The industrial materials from the site are reconfigured to create artful forms, new paving material for the boardwalk, and shelters.
An ecologically recovered landscape, urban agriculture and industrial spirit are the three major layers of the park, woven together through a network of paths where visitors are educated about green infrastructure within a lushly restored recreational area.