A few days ago, central mainstream news media Science and Technology Daily reported on the results of ecological restoration of Baiyang Lake, Hebei. The restoration of the Tanghe-River-Baiyang-Lake Wetland reflects the entire eco-environmental remediation of Baiyang Lake. ZEHO ECO, as the designer and constructor of the project, accepted an interview with the reporter of Science and Technology Daily and comprehensively introduced the past and present of the project from the aspects of innovative design concepts, close-to-nature solutions, and significant ecological effects.

November 30th Science and Technology Daily Ecology Special Page ©Science and Technology Daily

Attached article: Original text of Science and Technology Daily

More Movement and More Clear Water — Baiyang Lake’s Function of “Kidney of Northern China” Recovering

Reporter: Li He

7.4 meters

According to statistics, since 2018, Hebei Province has replenished Baiyang Lake with 1.304 billion cubic meters of water, with an average annual water intake of 430 million cubic meters, keeping the water level of the lake stable above 6.5 meters. In the past two years, the lake’s highest water level has reached 7.4 meters, which is a rare high water level in the past 20 years.

Photo of the Ecological Restoration of the Tanghe-River-Baiyang-Lake Wetland

The Tanghe-River-Baiyang-Lake Wetland is where Tanghe River flows into Baiyang Lake. Because of the reduction of upstream water and the continuous increase of industrial and agricultural water consumption, the natural water entrance to the lake was once artificially converted into farmland, dry land, etc., and the wetland ecosystem was seriously degraded. Through measures such as turning farmland back into wetland, restoring natural water system morphology and diversified wetland biological habitats, today’s Tanghe-River-Baiyang-Lake Wetland is filled with green grass, rippling blue waves and leisurely roosting whiskered terns and egrets. The beautiful scene of “Platform fields, sea of reeds, and paradise of birds” is gradually reappearing.

The restoration of the Tanghe-River-Baiyang-Lake Wetland reflects the whole eco-environmental remediation of Baiyang Lake. The State Council’s report on the ecological conservation of Xiong’an New Area and Baiyang Lake shows that the phased goals set out in the Baiyang Lake Ecological Environment Remediation and Conservation Plan (2018-2035) have basically been achieved. The overall water quality of the lake area has been upgraded from Inferior Grade V in 2017 to Grade IV in 2020, and the average water quality in the center of the lake has reached Grade III standard. In the first half of this year, the water quality of the 4 major rivers in Baiyang Lake and 50 river sections in the upstream basin has all reached or exceeded Grade IV, which is the highest level reached in the past 10 years.

Ecological water replenishment, rational regulation of the lake’s hydrology and water resources

Baiyang Lake is the largest freshwater lake in Northern China. In the 360 km2 lake area, there are 143 lakes and over 3700 intertwining gullies. As a scarce natural wetland in Northern China, Baiyang Lake is known as the “Kidney of Northern China” and plays an irreplaceable role in maintaining the ecological environment in the area.

However, since the 1950s, the arid climate, the continuous increase of industrial and agricultural water consumption, and the successive construction of upstream reservoirs have led to a continuing decrease in the amount of water entering Baiyang Lake. Water and soil erosion in the upper reaches and the embankment built in the lake has sped up the sedimentation of the lake’s silt and thus the water surface of the lake area has been incessantly shrinking.

Coupled with the discharge of urban domestic sewage and industrial sewage and aquatic cage culture, the water quality of Baiyang Lake has been continuously deteriorating. A villager living near the lake area said that when the pollution was the most serious, “even the birds didn’t fly over.”

On April 1st, 2017, Xiong’an New Area was established, and the remediation and conservation of the lake’s ecological environment started simultaneously. Baiyang Lake is in the lower reaches of nine rivers, so its remediation and conservation required comprehensive measures based on a bigger picture which concerned the entire river basin.

In China, there is a famous verse that goes, “If you ask why the pond is so clear, the answer will be fresh water from its source”. The lack of clean water supply and the sharp decline in ecological flow are important threats to the ecological environment of Baiyang Lake. Implementing ecological water replenishment and rational regulation of the lake’s hydrology and water resources are the most direct and effective measures to restore the lake’s ecosystem.

According to statistics, since 2018, Hebei Province has replenished Baiyang Lake with 1.304 billion cubic meters of water, with an average annual water intake of 430 million cubic meters, keeping the water level of Baiyangdian Lake stable above 6.5 meters. In the past two years, the highest water level of Baiyang Lake has reached 7.4 meters, which is a rare high water level in the past 20 years. Especially Baoding City, which is in the upper reaches of Baiyang Lake, has been scientifically allocating water resources and implementing ecological water replenishment for rivers flowing into Baiyang Lake. Among those rivers, Fuhe River, Xiaoyi River, Puhe River, Baigou River and other rivers have basically achieved a stable water supply with water entering the lake all year round, which has enabled a smooth ecological restoration of Baiyang Lake.

The 2021 Baiyang Lake Ecological Water Replenishment Work Plan of Xiong’an New Area, Hebei Province puts forward that this year, the planned ecological water replenishment volume is about 400 million cubic meters. Xiong’an New Area has also established and implemented an ecological water replenishment operation mechanism that scientifically adjusts the water replenishment period and water source and volume to increase hydrodynamics and water fluidity according to the ecological water demand of Baiyang Lake.

Systematic remediation to build a sustainable wetland ecosystem

Besides ecological water replenishment, He Lifeng, Director of the National Development and Reform Commission, also stated that the prevention and control of pollution in the Daqing River Basin and Baiyang Lake have been comprehensively promoted, and that the “source control, pollution interception and river remediation” system has been implemented and continuously promoted, steadily restoring Baiyang Lake’s function of being the “Kidney of Northern China”.

“The Tanghe-River-Baiyang-Lake Wetland Ecological Conservation Project, which has been implemented since 2018, is a typical case of comprehensive remediation. We adopted Nature-based Solutions and the principle of minimal human intervention, respected nature, and reduced the possibility of environmental damage. Fully considering the conditions of the site, the environment, the climate and other factors, we strove to reduce our interference to the natural environment in order to protect and restore it better.” said Min Ying, Executive President of the Design Group of Beijing ZEHO Waterfront Ecological Environment Treatment Co., Ltd.

At the junction of the wetland and surrounding villages, green embankments become ecological buffer zones, intercepting domestic sewage and agricultural non-point source pollution from surrounding villages and towns. The project team reshaped the wetlands ecosystem according to its landform, forming an ecological corridor dotted with blue and green. It optimized the route of the Tang River’s flow after entering the lake and increased its hydraulic retention time. And according to the wetland’s functional zoning and needs of landscape, the project team selected and integrated plant populations such as reeds to improve the plants’ absorption of eutrophic substances in the water body in order to purify the water.

“We hope that the area around Tanghe River’s entrance into the lake can be turned into a close-to-nature, low-impact and sustainable wetland ecosystem restoration demonstration area, and act as an exemplar for the organic combination and high-quality development of a region’s natural ecosystem and civilization,” said Min Ying.

The water at Baiyang Lake has become clearer. The water surface has become larger. And the wetland ecosystem and the lake’s function of the “Kidney of Northern China” are gradually recovering. Data show that when the Baiyang Lake Wetland Nature Reserve was established in 2002, 192 species of wild birds were recorded. In recent years, through increased efforts to protect the lake, wild birds have continued to increase, and the number of species recorded has increased to 230. In the observations from the winter of 2020 to the spring of 2021, 48 great bustards, national first-level protected birds, were recorded. In order to protect the lake’s aquatic biodiversity, Hebei Province has scientifically set fishing closure periods for the lake, and has released and proliferated over 150 million aquatic species accumulated. Species that have not been seen in the lake for many years, such as the Chinese bitterling, the snakehead, and the yellow catfish, have reappeared.

“Perch, which have not been spotted in the lake for over 30 years, has now reappeared in Baiyang Lake." said Zhang Fuqing, the cadre of Xiaozhangzhuang Village, Anxin County, who has been living by the lake since he was a child. He said that the perch has prime requirements for water quality, and its re-emergence also proves that the water quality of Baiyang Lake has improved.

Controlling sources and intercepting pollution to prevent even a drop of sewage from entering Baiyang Lake

Zhao Xianwei, Division Director of the Water Ecology and Environment Division of the Hebei Provincial Department of Ecology and Environment, said that the Baiyang Lake remediation will also focus on the domestic pollution of native villages, the accumulated pollution of the sediment in the lake area, and the secondary pollution of tourism and shipping. A series of powerful measures will be implemented and exploratory practice will be conducted.

Domestic sewage and garbage from the native villages are also important sources of Baiyang Lake’s pollution. According to statistics from the former Environmental Protection Bureau of Baoding City, the inflow of nitrogen and phosphorus into the villages in the lake area accounted for 1/4 and 1/3 of the total inflow of nitrogen and phosphorus into the basin, respectively.

While rapidly advancing the construction of Xiong’an, Hebei has also strengthened the protection of the only water body in the New Area, Baiyang Lake, and launch the slogan “prevent even a drop of sewage from entering Baiyang Lake”. According to Hebei Province’s requirements to “ensure that the lake area’s water quality reaches Grade IV in 2021, and strive to partially reach Grade III”, the quality of effluent water let out by conventional sewage treatment plants’ discharge standards does not meet the requirements for entering the lake. Because of this, in the past, domestic sewage from the urban villages in the lake area was discharged as “inverted discharge”, transporting sewage to treatment plants in the peripheral towns for centralized treatment, which was not only costly but also prone to leaking.

But now, in Baiyang Lake’s urban villages, domestic sewage from the villagers’ homes enters the deep denitrification equipment through a pipeline network, and the treated water enters small ponds and other water bodies for further purification…Participated by the Chinese Academy of Sciences’s Ecology Center and Beijing CSD Bize Environmental Technology Co., Ltd., this project in Baiyang Lake’s urban villages is of exemplary significance to the deep denitrification of sewage. The SADeN® technology jointly developed by the two parties is used as an advanced treatment unit, and plays an important role in the deep removal of nitrogen and phosphorus.

“After sewage undergoes secondary biochemical treatment, apart from nitrogen and phosphorus indicators, other indicators can reach the Grade IV surface water standards. Then, through the SADeN® technology, we intensify the treatment of nitrogen and phosphorus, and the total nitrogen concentration in the water gets basically controlled at a stable level of under 1.5 mg per liter. Subsequently, through the deep purification of constructed and natural wetlands downstream, ultra-clean sewage discharge is finally achieved,” said Dr. Sun Yilu of the Research Center for Eco-Environment of the Chinese Academy of Sciences. Dr. Sun said that, as the result of a rural sewage treatment project with today’s highest discharge standards, the sewage after the deep denitrification treatment meets the discharge requirements of the lake. For Baiyang Lake, it also plays a part in the lake’s ecological water replenishment.

“Baiyang Lake’s ecological environment remediation is not only to remedy the lake itself, but to remedy its entire basin,” said Gao Yinghua, Director of the Ecology and Environment Bureau of Xiong’an New Area. The director stated that the eco-environmental remediation of the basin is systematic, and that we should next “promote the remediation and conservation of the entire basin, including upper and lower reaches, left and right banks, and the inside and outside of the lake.”