China News Service, Beijing, July 21st, title: What are the hidden dangers of urban flooding into rivers?

  China News Agency reporter Ruan Yulin

  "Flood broke out. The city has accumulated water and becomes a river. Can the tap water still be drunk?" "What environmental impact does the flood bring?" Ma Jun, director of the Public Environmental Research Center, said in an interview with a reporter from China News Agency in Beijing on the 21st. Source pollutants may cause water pollution. People in the affected areas should pay special attention to the sanitation and safety of drinking water.

  In addition, environmental remediation and disinfection treatment should be carried out after the flood to prevent the occurrence or prevalence of infectious diseases.

  Since July 17, Henan Province has experienced continuous heavy rainfall.

Affected by heavy rainfall, some rivers in Henan have over-alarm and over-historical floods, resulting in a significant increase in the risk of mountain floods and geological disasters in the mountainous areas of western and northwestern Henan Province, rapid rise of reservoir water levels, and large-scale urban waterlogging and farmland waterlogging.

On July 21, Henan, Zhengzhou, the second day of heavy rain, after a night of rescue and rescue, the accumulation of water in the stagnant water section decreased significantly, but there were still serious water accumulations in many places on the street.

The picture shows the streets of Zhengzhou after the flood subsided.

Photo by China News Agency reporter Li Guigang

What are the effects of floods on the environment?

  Ma Jun said that floods will have a considerable impact on the urban environment. In plain areas, it will mainly lead to water accumulation and waterlogging. After this heavy rain, Zhengzhou experienced waterlogging.

In mountainous areas, some areas will also be affected by disasters such as mountain torrents and mudslides.

  Ma Jun said that the floods will have a great impact on municipal facilities such as urban water supply and drainage, as well as infrastructure such as transportation, roads, and culverts.

  In particular, floods may have an impact on the water supply, affecting water sources and water supply pipelines, causing water shutdowns and pollution of the water supply system.

Floods will also pose challenges to the urban drainage system, causing serious waterlogging and waterlogging, which will have a greater impact on the urban environment and cause drainage overflow.

  At the same time, non-point source pollution in cities, including garbage, dead wood, plants, and dead pets, livestock and poultry that were not properly treated, will be brought into urban streets and drainage systems with floods, which will cause pollution.

If some cities do not have a good rain and sewage diversion system, the sewage treatment plant cannot handle the excessive incoming water, which will lead to the direct discharge of sewage.

  Some experts pointed out that the flood contains a lot of sediment, other suspended matter, and even some industrial and mining wastewater, pesticide residues, etc.

After these pollutants enter the water body, they will cause the pollution of drinking water sources.

As rivers and lakes are connected to groundwater, they may also affect the quality of groundwater.

The flood washed the pollutants from the upstream to the rivers, lakes, and coastal estuaries downstream. For the entire basin, the problem of pollutants flowing into the river is more serious.

On July 21, 2021, the main urban area of ​​Zhengzhou City in Henan Province was hit by heavy rain.

Recently, Zhengzhou has experienced a rare and continuous heavy precipitation weather process, and the city has suffered heavy rains and extremely heavy rains, and caused floods.

Photo by Wang Zhongju issued by China News Agency Photo source: CNSPHOTO

How to prevent security risks?

  How to prevent safety hazards in flood?

Ma Jun reminded that, first of all, don't walk barefoot in the flood, it is easy to get hurt and get infected, and it is also easy to get injured and slip.

Try to wear shoes, but wet shoes should be cleaned and replaced in time.

  Secondly, wash your hands or shower with running water after going home, and change your clothes when they get wet to prevent skin diseases and keep them dry.

  Third, the flood season is the season of high humidity and high heat. Meals are prone to spoilage. Pay attention to refrigerating meals. High humidity weather can easily cause pests and mildew. The elderly and children should pay attention to removing dampness and dry skin.

  Fourth, the roads in the city with stagnant water are slippery and pass slowly. People who drive should be especially careful when driving.

It is also necessary to prevent the risk of electric shock, and be especially far away from wires and street lights; the manhole cover on the road may be opened and dropped by excessive drainage, so take precautions.

  From a safety point of view, individuals should not stay outdoors for long periods of time, try to stay in high terrain, avoid mountainous areas, and avoid high-risk areas that are prone to mudslides and landslides.

  Ma Jun said that the rare heavy rainfall in Zhengzhou has caused waterlogging, the subway station system has been flooded, and rare disasters have occurred. As the public, it is necessary to pay attention to extreme weather, pay attention to the official warning information, and avoid danger in time.

  It is reported that during the heavy rainfall, the Henan Meteorological Department issued early warning information on the entire network, and issued more than 1,100 early warning information through SMS, WeChat, Weibo, website and other channels, reminding more than 45 million persons in charge; various new media of the Meteorological Department More than 300 pieces of information including forecasts and warnings, rain conditions, and scientific knowledge were released, covering more than 100 million people.

  Experts said that timely access to early warning information is essential when floods come. Relevant departments should strengthen monitoring and consultations, grasp rain and rain, and the situation of water conservancy facilities such as reservoirs and dams, and disseminate relevant information to the society in a comprehensive and high-density manner Early warning.

Preventing the spread of infectious diseases after the flood

  "After the flood subsides, the public environment such as urban streets and roads must be cleaned and disinfected in time to avoid causing infectious diseases," Ma Jun reminded.

  Experts in the industry pointed out that environmental remediation and disinfection treatment should be carried out immediately after the flood to prevent and control the occurrence or prevalence of infectious diseases, and to protect the health of the people in the disaster areas.

The indoor and outdoor environment of the affected people, and the external environment of the villages and streets in the disaster-stricken area shall be completely eliminated.

At the same time, to ensure the safety of drinking water sources, thoroughly clean and disinfect contaminated drinking water sources and rural wells to prevent water environment risk accidents.

  "Some of the effects are visible, and some are potentially harmful," Ma Jun said. The impact of floods on roads and railway subgrades should be checked, and the safety of dikes and reservoirs should be paid special attention to. Various facilities affected by floods should be inspected in time. , Electrical appliances should avoid water ingress to prevent secondary environmental risks and disasters affected by floods.

At the same time, speed up the environmental improvement of disaster-affected points, hidden danger points, and secondary disaster points to fundamentally prevent and control secondary environmental risks caused by disasters.