Nandu River

Nandu River

This entry is compiled and applied by "popular science China" Science Encyclopedia

to examine

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Nandu River, also known as Nandu River, was called limushui in ancient times. It is the largest river in Hainan Island of China. It originates from Nanfeng mountain in the south of Nankai Township, Baisha Li Autonomous County, Hainan Province. The main stream slants through the middle and north of Hainan Island, flows through Baisha, Qiongzhong, Danzhou, Chengmai, Tunchang, Ding'an, Qiongshan and other cities and counties, and finally flows into Qiongzhou Strait in Sanlian community of Meilan District, Haikou City. The total length is 333.8 km, the gradient is 0.72 ‰, the total drop is 703 m, and the drainage area is 7033 square km. Songtao Reservoir is built in the upper reaches of the main stream, which is the largest artificial lake and the largest water conservancy project in Hainan Province.

Name source

Nandu River is the mother river of Hainan people. For a long time, the name "Nandu River" has not been tenable. Some people think that this is because people from southern Fujian crossed the river to the south, so they called it Nandu River. In fact, this is a wrong understanding. In history, the ancestors of Lingao lived in the Nandu River Valley and the northwest of Hainan Island, including the fertile coastal areas of Wenchang, Haikou, Qiongshan, Chengmai, Danzhou and Lingao, and then gradually expanded to the coastal areas of the whole island. The word "Nandu River" is named after Lingao dialect, because the pronunciation of "Nandu River" coincides with the saying of river water in Lingao dialect. As an important document for the study of Chinese historical geography, the summary of history reading Fang Yu describes the position, situation, and strategies for advancing and retreating of the prefectures before the Ming Dynasty. It is known as the "tortoise mirror of ancient and modern times and the medicine stone of peace". In the summary of history reading Fang Yu, the name of Nandu River is "local people call water as a river, so it's named". In the Lingao dialect, water is "Yi", which is well known. If the local people recorded in the book are not Lingao people, are there any other people in Hainan Island who "call water for you" It was named after Lingao dialect (Lingao dialect) spoken by Lingao people in Nandu River Basin

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characteristic

Nandu River is rich in water resources and has a large flow. The climate of the basin has obvious dry and wet seasons, and there are many rainstorms, so the river flow and water level often rise and fall. Every time after a rainstorm, mountain torrents break out and the river rises sharply, reaching the maximum flood peak immediately. There are two peaks of water level in a year, one in May, the other in September and October. Songtao Reservoir was built in the upper reaches of Nandu River in 1961, with a capacity of 3.1 billion cubic meters. It has the benefits of flood control, irrigation and power generation, and plays an important role in overcoming the unstable flow. The river bed gradient of Nandu River Delta is small, and the channel siltation is fast. When there is storm and rain in summer and autumn, the tide flows backward, and sometimes there are flood and tide disasters

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sand extraction

The middle and lower reaches of the main stream of Nandu River are rich in river sand resources. The sand mining of Nandu River has a long history and reached its peak in the 1990s. Driven by interests, there was once a phenomenon of disorderly, excessive and even predatory exploitation of river sand in Nandu River. Most of the sand mining is concentrated on the embankment 1.8 km from the original TANKOU power plant in Qiongshan city to the Nandujiang bridge. At most, there are nearly 100 sand mining points, and some owners have been indiscriminately digging in the river for a long time without a license. This kind of unplanned and disordered mining activity makes the river channel form irregular section, the riverbed is uneven, and some river sections even collapse, which endangers the safety of the river channel and bridge, and even causes the salty tide upstream of the estuary, shoreline retreat and other problems. Relevant data show that in the past 20 years, about 500 mu of farmland has been destroyed due to sand mining. In the past 10 years, 17 collapses occurred in the riverbank section of the surrounding highway.

In the future, attention should be paid to sand mining in the Nandu River. Recently, the sand mining planning in the Nandu River, which passed the expert evaluation, clearly limits the scope of sand mining and delimits three forbidden mining areas. There are 3 main mineable river sections and 34 mineable areas.

Experts believe that river sand mining should be sustainable, and the annual mining quota should be strictly controlled. Combined with the annual sand mining amount of Nandu River, it is suggested that the sand mining amount should be controlled between 1 million cubic meters and 1.2 million cubic meters per year.

On the premise of ensuring flood control safety, river regime stability and meeting the requirements of environmental protection, the plan has scientifically and reasonably planned the no mining area and mineable area.

The total length of the three banned river sections is 23.8 km. It is understood that the total length of the three banned river sections of sand in Nandu River is 23.8 km

Nandujiang No.1 is from 1000m upstream of the water intake point of Jinjiang town waterworks in Chengmai County to 1000m downstream of Jinjiang bridge. The forbidden mining section is about 3.5km long. There is a water intake point of Jinjiang town waterworks in the upper reaches of the section. There are two river crossing highway bridges in the middle reaches of the section. On both sides of the section are the flood dike of Jinjiang Town, so it is designated as the forbidden mining area.

The second is the section from 4340m upstream of Longtang dam to TANKOU power plant. The section is about 8.8 km long, with Longtang dam, Haikou Longtang drinking water source protection zone and Longtang station, a national hydrological station.

The third is from 500 meters upstream of Nandujiang bridge to Mayu village, Haikou City. The length of the reach is about 11.5km. There are many large bridges in the reach. Due to the excessive exploitation of river sand in the 1990s, the amount of sand can not be replenished to the initial equilibrium state in a short time, so it is classified as no mining area

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Pollution investigation report

Background notes

Nandu River is the mother river of Hainan, which contains the growth of all things in Hainan. As a native, we should protect our own mother river. Since the reform and opening up, Hainan's economy has developed, but with the development of pollution is becoming more and more serious, our mother river is also hard to escape. Therefore, we should pay attention to the problems caused by pollution.

Purpose of investigation

In order to find the source of pollution in Nandu River, we can let people from all walks of life understand the seriousness of the pollution problem, and remind people from all walks of life to take the strategy of sustainable development.

1. Call on people to protect Nandu River and its surrounding environment, and at the same time, tell people to protect water resources and environment in a wider range.

2. Cultivate and test students' practical ability of color meeting.

3. To enable students to better show their strengths and increase their knowledge in all aspects.

4. Cultivate the spirit of unity and cooperation

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Scope of research

1. The history of crossing the river in the south.

2. The environmental condition of Nandu River before being polluted.

3. The pollution of Nandu River and the surrounding environment.

4. Causes of pollution of Nandu River and its surrounding environment.

5. The influence of crossing the river to the South on people.

Study the method to be used

1. Consult relevant books and newspapers.

2. Search relevant information on the Internet.

3. Inquiry and investigation of the older generation.

4. Practice investigation.

5. Visit relevant personnel.

5. Interview and investigate the masses and their feelings and attitudes on this matter.

7. Discuss the results of the investigation, present comments and summarize

Conditions for research

Venue: Nandu riverside, computer room, bookstore.

Equipment: computer, printer, camera, chemical instrument, etc.

Division of labor

1. Planning: Wang Feng, Wang Jia.

2. Investigation: Lin zhongzi, Wang Xiujie and Wang Jia.

3. Record: Zheng Xiaomei, Xu Hua.

4. Statistical analysis: Wang Feng, Xie chunman.

5. Detection of water pollution: Xie chunman, Wang Xiang.

6. Summary: Wang Feng, Wang Xiang, Zheng Xiaomei.

Investigation methods

1. Questionnaire method: the total number of questionnaires was 200, and 172 valid questionnaires were collected.

2. Oral way: all the members of the group take part in and take turns.

3. Internet access: by the investigation team.

Survey results

《1》 Summary of the questionnaire survey:

According to the survey, due to the rising pollution level of Nandu River, about 68.7% of the people are not satisfied with the current management of Nandu River, and about 35.4% of the people reflect that the water of Nandu River is turbid and the pollution is becoming more and more serious. Some individual residents also reported that there was a chemical plant not far from their home, where the River gave off a bad smell. The pungent odor and the stinky waste gas brought environmental problems to the residents. They often saw dead fish floating on the load surface. According to the survey results, 72.1% of the people thought that the pollution of Nandu River came from illegal chemical plants. In addition, 24.8% of the people think that the "three wastes" of large-scale factories are not handled properly, and the "three wastes" emitted by them make the pollution level of Nandu River rising. 83.3% of the people asked the government to strengthen the supervision of the factories, and 21.7% of the people asked the government to restrict the pollutants emitted by the factories.

《2》 Record summary:

The pollution sources of Nandu River are mainly domestic pollution and industrial pollution. The domestic pollution mainly comes from the residents or villagers in neighboring counties and towns, especially the domestic waste in Baisha, Tunchang, Ding'an and Chengmai counties

Chinese PinYin : Nan Du Jiang