Returning Nature's Borrowed Clean Freshwater: A Sustainable Model in Shanghai, China

Freshwater is the lifeblood of our planet and people. It supports a healthy ecosystem and fuels industrial development. However, freshwater resources worldwide are limited while urban development continues to increase pressure on water sources. About 80% of the world's people are threatened with insufficient water quantity or quality. The World Bank stated in 2016 that the world will only be able to meet the SDGs of the 21st century by ensuring a water-secure world for all.

China faces severe water scarcity, resulting in low freshwater per capita, uneven distribution, and urban water scarcity. Of China's 600 cities, 400 have an insufficient water supply, and 110 face severe water shortages. These are primarily cities in the northern part of the country and megacities with high water consumption.

?Located at the Yangtze Estuary, Shanghai is China's largest city; it enjoys one of the most rapid social and economic development yet faces increasing water stresses. Globally, socio-economic development consumes large amounts of water resources. In urban environments, we "borrow" clean water from Mother Nature and then "return" grey and black water to it, contaminating more clean water.

What if we can restore "clean water" to the natural freshwater ecosystem? What if we could strive to cultivate a healthy environment with minimal or, ideally, negligible costs? In collaboration with Microsoft Corporation, Conservation International China is implementing a pilot initiative in Shanghai, specifically at the Upper Huangpu River. This initiative is a component of the joint partnership's commitment to water replenishment in areas globally facing water scarcity.

Why Upper Huangpu River?

Cheng Zhang, Program Director of Conservation International China: The Upper Huangpu River is one of Shanghai's key drinking water sources that one-third of Shanghai residents (6.7 million people) rely on. However, it faces challenges, particularly in poor water quality.

What are these challenges?

Cheng Zhang: this includes, on the one hand, pollution from agriculture, aquaculture, and livestock farming from its surrounding areas, direct pollutants from pesticide and fertilizer use, fish feed and other pollutants; on the other, there is insufficient treatment of domestic wastewater from surrounding communities. These water challenges are risking Shanghai's water security and have caused aquatic ecosystem degradation in the area.

How to face up to these challenges?

Cheng Zhang: Conservation International China has long been conserving the health of freshwater ecosystems in watersheds across China. Since last year, with the support of Microsoft, we have been working with local NGOs, with technical expertise from the China University of Geosciences, Wuhan, to demonstrate a cost-effective nature-based solution at Tianshanzhuang Village, a rural community in the Upper Huangpu River. The work aims to reduce pollution and secure quality water supply for Shanghai. It's like an effort to return clean water that local people "borrowed" from nature to sustain their daily life and agricultural development.

?How do you return clean water in a cost-efficient way?

Cheng Zhang: we do this by installing a restored/artificial wetland system for rural wastewater treatment. At the same time, we promote better water governance practices in surrounding rural communities. This artificial wetland system is supported by water channels and constructed smaller wetlands at different altitudes. It works as an unpowered purification system, effectively retaining and capturing nitrogen and phosphorus, facilitating the sedimentation of particles in flowing waters. This is accomplished by restoring the natural wetland ecosystem with local plant species.

Concurrently, we involve the community in the construction and restoration efforts, offering learning and capacity training opportunities. This approach promotes self-sustained maintenance of the artificial wetland system and fosters enhanced capabilities for improved water governance within the community.

The artificial wetland system can operate without power and is easy to maintain. Hence, it's more cost-effective than a wastewater treatment factory in a rural community that is not densely populated. And there are multiple benefits from it.

What are the benefits?

Cheng Zhang: the first and foremost is volumetric water benefits, which means the total amount of "clean water" we help return to nature. The project will measure the annual amount when the artificial wetland fully functions. Secondly, the environmental condition in the Upper Huangpu River will be improved with cleaner water. Consequently, this improvement will foster ecologically friendly development opportunities for rural communities, including eco-tourism, nature education, eco-agriculture, and rural lifestyle exploration activities. Furthermore, local people who are directly engaged in the project implementation can earn additional income and gain knowledge and skills in water governance. Last, the decrease of COD, TN, and TP (the primary pollutants in rural wastewater) emissions and the restored wetland ecosystem achieved by the project can help local communities adapt to climate change.