The Pearl River Delta is characterized by a uniquely Chinese dike-pond system of integrated agriculture and aquaculture, which is operated on a geographical and economic scale unrivaled elsewhere in the world. The emergence of the dike-pond is tightly associated with flood control. Its highly flexible production system contributes to its wide dissemination in the Delta. It is a scientific and environmentally conservative approach to agro-production used in flood-prone low-lying areas for centuries.
In the past thirty years, however, pressure coming from two concurrent processes of urbanization—a city-centered urban sprawl and a dispersed rural-based industrialization—has compressed the space of the dike-pond landscape and caused its typological changes. Today, a large portion of the dike-pond is either converted or occupied, leading to severe water management and treatment problems. Since the late 1990s, approximately 4,000 square kilometers of farmland have disappeared every year in China. According to a national lands survey, 130,000 square kilometers of farmland—equivalent to about half the area of Germany—disappeared in the country’s rush toward urbanization between 1996 and 2009.
And it hasn’t stopped there. The Pearl River Delta is in the midst of large-scale ecological and economic shifts in its food production systems, and more change is sure to come. Current and future challenges of the dike-pond system include: the shrinking area of the dike-pond system and rising demand for fish protein; the discontinued practice of a traditional, organic food economy coupled with an increasing consumer desire for sustainable produce; and uncertainty and variability in freshwater supply due to the effects of water quality degradation and global climate change. This crisis calls for alternative models of food production amidst the irresistible urbanization.
Located in southwest Foshan City, Jiuquchong is an underdeveloped region that represents the trade-off between promoting economic growth through further urbanization and protecting fertile farmland against accelerated urban expansion.
Like many other villages in the Delta, Jiuquchong once enjoyed years of economic prosperity from its dike-pond landscape. Its closeness to the city hub, however, has cost the region a continuing period of pond infill by new development over the past few decades. The energy balance between the dike and the pond has also been broken since more dikes are converted into modern freshwater aquaculture ponds to satisfy the worldwide demand for fish protein.
Although a large portion of the dike-pond is preserved owing to a national farmland protection policy, it is not economically viable. The productivity of the dike-pond system is negatively affected by its sequential layout. Pond sequential layout causes a problematic concentration of nutrients for the inner ponds; pond water quality decreases, as it is further away from the irrigation channel; and the inner ponds tend to have a higher volume of sediment accumulation, higher phosphorus, higher nitrates, and a consequent lower water transparency.
As a territory in the shadow of the cities, what can we envision for the dike-pond landscape in Jiuquchong: losing the dike-pond to the urban expansion? A passive preservation of the dike-pond? Or a synergistic development with urbanism? Is a balance between ecology and economy even achievable?
Through learning about the complex historical model and the bottom-up wisdom, my recent graduate thesis at UC Berkeley attempted to re-envision a future for Jiuquchong, posing the possibility of reconciling the contradiction between urbanization and agrarian landscape preservation. The project proposed a central spine of hybridization for the future of Jiuquchong, on which new ecologies, new economies, and cultural identities are interwoven with the process of reclaiming the productive dike-pond landscape. This central spine is, at first sight, a 1.5-kilometer roadway that connects the village to the east with newly developing urban fabric. Upon deeper study, it is actually a landscape-based infrastructure that combines freshwater aquaculture, sediment harvesting, lotus tourism, and wastewater management and treatment. It is systematic, flexible, polyfunctional, and accessible to the public.
The whole region is interrelated through a complex set of hydrologic flows and material exchanges that link the multifunctional dike-pond with the local markets and factories. The new hydrologic infrastructure links the pond occupation, preservation, and conversion zones to improve the water quality and productivity of the whole system. It collects multi-source water, utilizes the nutrient-rich water, then treats and discharges it downstream.
The Jiuquchong vision is just one iteration of reconciling the contradiction between urbanization and agrarian landscape preservation. The dike-pond landscape is highly adaptive and complex, as demonstrated in its long history. Through subtle rearrangement and hybridization, the dike-pond system can adapt to different fluvial conditions and ecological adjacencies, become part of the adaptive response to climate change, and incorporate and support the regional economy development. Through learning from the historical model and “bottom-up” wisdom, we can reconcile the complexities and embrace a sustainable and productive future.
Xiuxian Zhan is a designer in the Sausalito studio.
Posted by Xiuxian Zhan in Ecology, Landscape Infrastructure on