What Are the Different Types of Surface Water Drainage?

Surface water refers to the general term of dynamic and static water on the surface of the land. ^[1] . It is one of the important sources of water for human life and the main component of water resources in various countries.

On May 7, 2019, the Ministry of Ecology and Environment announced the first quarter of the national surface water assessment cross-section water environmental quality ranking list, and notified the national water environment quality and the completion of the target tasks in the first quarter.

Chinese name: Surface water
Foreign name: surface water

Concept: Water that exists on the surface of the crust and is exposed to the atmosphere
the main form: River, lake or freshwater wetland
Form: Natural precipitation and snow accumulation over the years

The dynamic volume of surface water is river runoff and glacial runoff, while the static water volume is expressed by the storage capacity of various water bodies. The world's surface water reserves are 24,254 trillion cubic meters, accounting for only 1.75% of total global water reserves; however, surface water bodies are constantly being replenished by atmospheric precipitation. After runoff and convergence, there are 43.5 trillion cubic meters of river runoff and 23,000 Billion cubic meters of glacial runoff flows into the ocean, accounting for 94.7% of the total 47 trillion cubic meters into the sea, and plays a very important role in the global water cycle. In addition, the inflow region generates 1.0 trillion cubic meters of river runoff each year, which flows into inland lakes and is consumed by evaporation. The form of surface water is closely related to climate. Of the world's 149 million square kilometers of land, about 62% of the area is covered by rivers, lakes, and swamps, about 12% is covered by glaciers, and the remaining 26% is desert and semi-desert.

Causes of surface water formation

Surface water accumulates through the accumulation of natural precipitation and snow over the years, and is naturally lost to the ocean or disappears through evaporation, and seeps to the ground.

Although the natural water source of any surface water system is only from precipitation in the catchment area, there are many other factors that affect the total amount of water in the system. These factors include the water storage capacity of lakes, wetlands, and reservoirs, soil seepage, and characteristics of surface runoff in this catchment area. Human activities have a significant impact on these characteristics. Humans build reservoirs to increase water storage, and lighten wetland water to reduce water storage. Human reclamation activities and the construction of ditches increase the volume and intensity of runoff.

Surface water carrier

Surface water is water that exists on the surface of the earth's crust and is exposed to the atmosphere. It is a general name for four types of water bodies: rivers, glaciers, lakes, and swamps. It is also called "land water". It is one of the important sources of water for human life and the main component of water resources in various countries.

Surface water river

Rivers are widely distributed, and the amount of water is updated quickly and easily accessible. It has always been the main source of water for human development.

Surface water conditions in an area are usually expressed in terms of river runoff. In addition to river runoff being directly affected by precipitation, underlying factors such as topography, geology, soil, and vegetation also have a significant effect on runoff. Rainwater, snow and ice melts the surface or underground rivers. The part of groundwater recharged river is called base flow, the water quantity is relatively stable, the water quality is generally good, and it has important value for water supply. The total length of large and small rivers in China is about 420,000 kilometers, with a total runoff of 2,711.5 billion cubic meters, accounting for 5.8% of the world's runoff. Although the number of rivers in China is large, the regional distribution is very uneven. 96% of the country's total runoff is concentrated in outflow basins, with an area accounting for 64% of the total area of the country, and inland basins only account for 4%. 36%. Winter is the dry season in China's river runoff, and summer is the season of high water. This part of the water volume is relatively easy to develop and utilize surface water resources. Floods in the flood season are difficult to use directly, and reservoirs need to be built for regulation.

Surface water glacier

Polar glaciers and ice caps are difficult to extract and use in large quantities, but alpine glaciers at lower and middle latitudes are more important.

Water resources. Alpine glaciers are solid reservoirs that store solid precipitation, release ice, snow, and melt water, and have a replenishing and regulating effect on the river, making the annual runoff of the river relatively stable. Glaciers in China are all mountain glaciers, which can be divided into two types, continental glaciers and marine glaciers. Among them, continental glaciers account for more than 80% of the country's glaciers. China's glaciers are distributed at the source of rivers in the northwest and southwestern regions, with a total area of about 56,500 square kilometers, total reserves of about 5 trillion cubic meters, and an average annual melting volume of glacial water of 55 billion cubic meters. Glacier melt water is one of the water sources of inland rivers in northwestern China. It has the characteristics of more water in dry years and less water in humid years, which is very beneficial to agricultural production.

Surface water lake

Lakes and reservoirs are bodies of water that store and regulate runoff, and are renewed slowly. Most inland lakes are saltwater lakes,

Water supply is not significant, but contains mineral resources. Outflow lakes and artificial reservoirs have the function of regulating runoff to purify river water and breeding aquatic products, and can improve the comprehensive utilization of river runoff. The distribution of lakes in China is very uneven, with a total area of about 74,280 square kilometers (more than 2,800 lakes above 1 square kilometers), mainly distributed on the Qinghai-Tibet Plateau, the middle and lower reaches of the Yangtze River and the lower Huaihe River. It accounts for about 45% of the total area. In addition, China has successively built more than 86,000 artificial lakes and various types of reservoirs. China's total lake water storage is approximately 733 billion cubic meters, of which 30% is fresh water. With the increase of human activities, some lakes in the arid areas are facing the danger of shrinking and drying up. The lakes in economically developed areas have problems of blind reclamation and lake water pollution.

Surface water marsh

A marsh is a unique body of water, an over-wet area where some wet plants grow. The distribution of swamps in China is very

The area of peat swamps and submerged swamps alone amounts to more than 113,000 square kilometers, mainly distributed in the low-lying areas of the Sanjiang Plain in the northeast, the Nenjiang Plain, and the upper reaches of the Yellow River and some coastal areas. Most of China's swamps are located in low-level and high-water areas, and the potential soil fertility is high, which is an important object for China to further expand its arable land area.

Combined use of surface water and groundwater

In order to promote a balanced supply and demand of water resources in a river basin, region or irrigation area, reasonable unified development, utilization and management of surface water and groundwater are carried out. In farmland irrigation, the main form of combined use is well-ditch combination. In some areas, large-scale water diversion and water transfer projects have been constructed to form a system with the original well irrigation districts. In some large artesian irrigation districts, due to the lack of surface water resources, machine wells have been constructed in irrigation districts. The Central Valley in California, the Indus Plain in Pakistan, the Ganges Plain in India, and the Huanghuai Plain in China are all areas where large areas of surface water and groundwater are used. Through the combined use of surface water and groundwater, the following purposes can be achieved.

Regulate surface runoff. Utilize the water storage function of the aquifer to store the excess surface water during the high water period for the dry season.

Improve groundwater quality. Regulating the amount of surface runoff can dilute the groundwater with high salt content. Some irrigation districts in Pakistan and Israel have used this method to reduce the salt content of groundwater. In the Heilonggang area of the Huanghuaihai Plain in China, shallow mineralized groundwater has also been "salted and desalinated." In the Netherlands, water with higher temperatures in the summer is also recharged underground, and in winter, greenhouse flowers and vegetables with higher water temperature requirements are extracted.

Regulate groundwater level. The construction of large reservoirs and irrigation areas has increased the recharge of groundwater, which has caused the groundwater level to rise, resulting in waterlogging and secondary salinization of irrigated land. In these areas, the exploitation and utilization of groundwater can reduce the groundwater level and cooperate with the ground drainage to carry out comprehensive management of drought, waterlogging and saline-alkali; Long-term over-exploitation will form a large-scale groundwater level falling funnel, causing hazards such as ground subsidence and seawater intrusion in coastal areas. In this case, surface water can be introduced to reduce groundwater extraction and recharge groundwater to regulate the groundwater level.

In the management, the surface water should be cited, and the aquifer pumping and recharging should be reasonably scheduled to achieve the optimal utilization of irrigation water sources. Corresponding management measures shall be formulated in the application management. Administrative measures: Centralized and unified management of surface water and groundwater; Legal measures: Allocate a certain amount of pumping quota to users; Economic measures, reasonable calculation of surface water and groundwater irrigation water charges.

Surface water laws and regulations

Surface Water Law of the People's Republic of China

On January 21, 1988, the Standing Committee of the Sixth National People's Congress of the People's Republic of China passed the Water Law of the People's Republic of China. The main contents are: scope of adjustment. To develop, utilize, protect and manage water resources in the territory of the People's Republic of China, prevention and control of water damage must comply with water laws. Water resources include surface water and groundwater. Clear ownership of water resources, that is, water resources are owned by the whole people and collectively. Strengthen the management of water resource utilization through economic means such as collecting water and water fees. Strengthen the government's leadership in flood prevention and flood control work, and stipulate measures that flood control command agencies can take in emergency situations.

The 29th Meeting of the Standing Committee of the Ninth National People's Congress of the People's Republic of China revised and adopted the new version of the Water Law of the People's Republic of China on August 29, 2002. The revised Water Law of the People's Republic of China since 2002 Effective October 1.

Environmental Protection Law of the People's Republic of China

The Environmental Protection Law of the People's Republic of China is a national law enacted to protect and improve the environment, prevent pollution and other public hazards, protect public health, promote ecological civilization, and promote sustainable economic and social development. The eighth meeting of the Standing Committee of the General Assembly was revised and adopted on April 24, 2014. The revised "Environmental Protection Law of the People's Republic of China" is now promulgated and will come into effect on January 1, 2015.

Environmental Quality Standards for Surface Water

In order to implement the "Environmental Protection Law" and "Water Pollution Prevention Law", strengthen the management of surface water environment, prevent and control water environment pollution, and protect human health, the "Surface Water Environmental Quality Standard" is now approved as the national environmental quality standard. Jointly issued by the General Administration of Quality Supervision, Inspection and Quarantine. This standard is compulsory, published by China Environmental Science Press, and implemented since June 1, 2002. Promulgated by the State Environmental Protection Administration on April 26, 2002. Standard name and number: Surface water environmental quality standard (GB 3838-2002)

Surface water quality ranking

On May 7, 2019, the Ministry of Ecology and Environment announced that the top five cities in the first quarter of the national surface water assessment cross-section water environmental quality were: Ya'an, Laibin, Yunfu, Jinchang, and Wuzhou. The bottom five cities (1 to 5) are: Lu Liang, Yingkou, Xingtai, Liaoyuan, and Jinzhong. The surface water assessment section of 30 cities including Siping, Changchun, Zhongshan and other cities has relatively good changes in the quality of the surface water environment, and the changes of the surface water assessment section of 30 cities including Luliang, Yingkou, and Shuozhou have relatively poor conditions ^[2] .

On May 7, 2019, the Ministry of Ecology and Environment also notified the national water environment quality and the completion of the target tasks in the first quarter. The overall quality of water environment across the country has improved. Among 1940 countries' surface water evaluation sections, the proportion of good water sections was 74.3%, an increase of 8.0% year-on-year; the proportion of inferior Class V sections was 6.0%, a year-on-year decrease of 3.6%. The main pollution indicators were ammonia nitrogen, total phosphorus and chemical oxygen demand. The prevention and control of water pollution is uneven, and the situation of meeting the water environment standards in some areas is still severe ^[2] .