The only major urban river site in Beihai, South China's Guangxi Zhuang autonomous region — formerly known as an area of heavy pollution — has taken on a cleaner and greener look after two years of water and environment improvement programs.

The 6.5-kilometer Fengjiajiang River runs through the inner city of Beihai and heads south into the Beibu Gulf. A total of 200 hectares of mangroves grow in the central and lower section of the river banks.

On the eastern side of the river mouth sits a mangrove forest in an ecological protection zone; on the other, the Silver Beach scenic spot, which received 4.28 million tourist visits from March to October.

Thus, the river's water quality is closely related to ecological protection, biodiversity, tourism and economic development.

Although Fengjiajiang River is important in many contexts, it did not receive significant attention or protection until 2018.

By then, there were around 133 hectares of shrimp ponds, 24 pig farms and 363 drainage outlets where rainwater and sewage were dumped without treatment along the river.

The deteriorating water had become a rising threat to the mangroves, wetland vegetation and aquatic life.

In March 2018, the city government initiated an environment improvement project on the river and nearby lands, tackling the problems head-on. A public-private partnership mode was adopted, and total investment reached 2.25 billion yuan ($342.2 million).

In December the same year, construction got underway. Pollution reduction and ecological restoration were made top priorities, and multiple measures were taken to realize them.

Over the past two years, about 30 kilometers of pipelines were laid to intercept sewage discharged to the river and channel it to treatment facilities. 540,000 cubic meters of sludge were removed from the waterways, as well as obstacles that blocked the river flow.

The river has also been replenished with reclaimed water as a way to improve water quality and help self-cleaning. The large pond areas have been retained, but are no longer used to keep shrimp. They have been planted with different kinds of aquatic plants to help purify the waters and offer habitats for water creatures.

On the banks, more than 30 kinds of plants have been cultivated in different sections to recover vegetation and filter the rainwater. Due to sea tides, the water is salty in the middle and downstream, so mangrove, alkaline grass and other saline plants have been planted there.

"The improvement work will be finished in December. To date, we have reduced the discharge of 16.5 million tons of wastewater to the river. Two year ago, the river water was rated grade V, the lowest water quality standard in China. Now it has been rated better than grade IV," said Zhang Qingxi, manager in charge of the environment improvement project from Beijing Drainage Group.

Biodiversity has increased in the area as more birds and small creatures living in mud flats can be observed, such as the spoon-billed sandpiper, a critically endangered species, and sandworm, an environmentally sensitive creature. Egrets may be the most frequently seen birds here.

"Environmental protection of the Fengjiahe River is important to achieve the city's sustainable development. I believe the gradually restored river will play a bigger role in maintaining a healthy city environment, improving people's well-being and driving urban development," Zhang added.