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Salt Tide
Salt tide is a phenomenon in which the lower course of a river, with its low altitude with respect to the sea level, becomes Seawater, salty when the discharge of the river is low during dry season, usually worsened by the result of astronomical high tide. The lower course Xijiang (''West River'') in Guangdong, China was periodically affected and has been widely reported since 2004, for bringing shortage of fresh water supply to the western part of the Pearl River Delta. The salinity level of Tap water, tap water at Zhuhai was reported to be as high as 800 mg per litre in late February 2006, more than 3 times higher than the World Health Organization standard of 250 mg. References *"Fresh-water crisis looms for Macau - Salinity keeps rising despite assurances", ''South China Morning Post'', Page A7 Hong Kong & Delta, published Thursday, February 23, 2006. Hydrology Rivers Freshwater ecology {{Geology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
River
A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases, a river flows into the ground and becomes dry at the end of its course without reaching another body of water. Small rivers can be referred to using names such as Stream#Creek, creek, Stream#Brook, brook, rivulet, and rill. There are no official definitions for the generic term river as applied to Geographical feature, geographic features, although in some countries or communities a stream is defined by its size. Many names for small rivers are specific to geographic location; examples are "run" in some parts of the United States, "Burn (landform), burn" in Scotland and northeast England, and "beck" in northern England. Sometimes a river is defined as being larger than a creek, but not always: the language is vague. Rivers are part of the water cycle. Water generally collects in a river from Precipitation (meteorology), precipitation through a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Altitude
Altitude or height (also sometimes known as depth) is a distance measurement, usually in the vertical or "up" direction, between a reference datum and a point or object. The exact definition and reference datum varies according to the context (e.g., aviation, geometry, geographical survey, sport, or atmospheric pressure). Although the term ''altitude'' is commonly used to mean the height above sea level of a location, in geography the term elevation is often preferred for this usage. Vertical distance measurements in the "down" direction are commonly referred to as depth. In aviation In aviation, the term altitude can have several meanings, and is always qualified by explicitly adding a modifier (e.g. "true altitude"), or implicitly through the context of the communication. Parties exchanging altitude information must be clear which definition is being used. Aviation altitude is measured using either mean sea level (MSL) or local ground level (above ground level, or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sea Level
Mean sea level (MSL, often shortened to sea level) is an average surface level of one or more among Earth's coastal bodies of water from which heights such as elevation may be measured. The global MSL is a type of vertical datuma standardised geodetic datumthat is used, for example, as a chart datum in cartography and marine navigation, or, in aviation, as the standard sea level at which atmospheric pressure is measured to calibrate altitude and, consequently, aircraft flight levels. A common and relatively straightforward mean sea-level standard is instead the midpoint between a mean low and mean high tide at a particular location. Sea levels can be affected by many factors and are known to have varied greatly over geological time scales. Current sea level rise is mainly caused by human-induced climate change. When temperatures rise, Glacier, mountain glaciers and the Ice sheet, polar ice caps melt, increasing the amount of water in water bodies. Because most of human settlem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seawater
Seawater, or salt water, is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5% (35 g/L, 35 ppt, 600 mM). This means that every kilogram (roughly one liter by volume) of seawater has approximately of dissolved salts (predominantly sodium () and chloride () ions). The average density at the surface is 1.025 kg/L. Seawater is denser than both fresh water and pure water (density 1.0 kg/L at ) because the dissolved salts increase the mass by a larger proportion than the volume. The freezing point of seawater decreases as salt concentration increases. At typical salinity, it freezes at about . The coldest seawater still in the liquid state ever recorded was found in 2010, in a stream under an Antarctic glacier: the measured temperature was . Seawater pH is typically limited to a range between 7.5 and 8.4. However, there is no universally accepted reference pH-scale for seawater and the difference between measurement ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xijiang
The Xi River (; ) or Si-Kiang is the western tributary of the Pearl River in southern China. It is formed by the confluence of the Gui and Xun Rivers in Wuzhou, Guangxi. It originates from the eastern foot of the Maxiong Mountain in Qujing City, Yunnan Province. Then it flows east through Guangdong, and enters the Pearl River Delta just east of the Lingyang Gorge in Zhaoqing. The main branch of the Xi River flows southeast through the delta entering the South China Sea at Modao Men, just west of Macau. The major cities along the Xi include Wuzhou, Zhaoqing, and Jiangmen. The other two main tributaries of Pearl River are the Dong River (literally, the East River) and Bei River (the Northern River). Other transliterations of the river's name include Hsi River and Hsi Chiang. As for other functions, it plays a vital role in carbon storage and transport in Southern China. The Xi River is facing some ecological challenges such as drought, invasive species, and pollution. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Guangdong
Guangdong (, ), alternatively romanized as Canton or Kwangtung, is a coastal province in South China on the north shore of the South China Sea. The capital of the province is Guangzhou. With a population of 126.01 million (as of 2020) across a total area of about , Guangdong is the most populous province of China and the 15th-largest by area as well as the second-most populous country subdivision in the world (after Uttar Pradesh in India). Its economy is larger than that of any other province in the nation and the fifth largest sub-national economy in the world with a GDP (nominal) of 1.95 trillion USD (12.4 trillion CNY) in 2021. The Pearl River Delta Economic Zone, a Chinese megalopolis, is a core for high technology, manufacturing and foreign trade. Located in this zone are two of the four top Chinese cities and the top two Chinese prefecture-level cities by GDP; Guangzhou, the capital of the province, and Shenzhen, the first special economic zone in the count ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
China
China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and borders fourteen countries by land, the most of any country in the world, tied with Russia. Covering an area of approximately , it is the world's third largest country by total land area. The country consists of 22 provinces, five autonomous regions, four municipalities, and two Special Administrative Regions (Hong Kong and Macau). The national capital is Beijing, and the most populous city and financial center is Shanghai. Modern Chinese trace their origins to a cradle of civilization in the fertile basin of the Yellow River in the North China Plain. The semi-legendary Xia dynasty in the 21st century BCE and the well-attested Shang and Zhou dynasties developed a bureaucratic political system to serve hereditary monarchies, or dyna ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pearl River Delta
The Pearl River Delta Metropolitan Region (PRD; ; pt, Delta do Rio das Pérolas (DRP)) is the low-lying area surrounding the Pearl River estuary, where the Pearl River flows into the South China Sea. Referred to as the Guangdong-Hong Kong-Macao Greater Bay Area in official documents, the region is one of the most densely populated and urbanized regions in the world, and is considered a megacity by numerous scholars. It is currently the wealthiest region in Southern China and one of the wealthiest regions in China along with the Yangtze River Delta in Eastern China and Jingjinji in Northern China. Most of the region is part of the Pearl River Delta Economic Zone, which is a special economic zone of China. The region is a megalopolis, and is at the southern end of a larger megalopolis running along the southern coast of China, which include metropolises such as Chaoshan, Zhangzhou-Xiamen, Quanzhou- Putian and Fuzhou. The nine largest cities of the PRD had a combined populatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tap Water
Tap water (also known as faucet water, running water, or municipal water) is water supplied through a tap, a water dispenser valve. In many countries, tap water usually has the quality of drinking water. Tap water is commonly used for drinking, cooking, washing, and toilet flushing. Indoor tap water is distributed through "indoor plumbing", which has existed since antiquity but was available to very few people until the second half of the 19th century when it began to spread in popularity in what are now developed countries. Tap water became common in many regions during the 20th century, and is now lacking mainly among people in poverty, especially in developing countries. Governmental agencies commonly regulate tap water quality. Household water purification methods such as water filters, boiling, or distillation can be used to treat tap water's microbial contamination to improve its potability. The application of technologies (such as water treatment plants) involved in pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zhuhai
Zhuhai (, ; Yale: ''Jyūhói''), also known as Chuhai is a prefecture-level city located on the west bank of Pearl River estuary on the central coast of southern Guangdong province, People's Republic of China, on the southeastern edge of Pearl River Delta. Its name literally means "pearl sea", which originates from the city's location at the mouth of the Pearl River meeting the South China Sea. Zhuhai borders Jiangmen to the west, Zhongshan to the north and Macau to the southeast, and shares maritime boundaries with Shenzhen and Hong Kong to the northeast across the estuary. Zhuhai was one of the original four Special Economic Zones established in 1980, as well as one of China's premier tourist destinations, being called the Chinese Riviera. While the city is located in the traditionally Cantonese-speaking province of Guangdong, a significant portion of the population is now made up of Mandarin-speaking economic migrants originally from inland provinces. The core of Zhuhai, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
World Health Organization
The World Health Organization (WHO) is a specialized agency of the United Nations responsible for international public health. The WHO Constitution states its main objective as "the attainment by all peoples of the highest possible level of health". Headquartered in Geneva, Switzerland, it has six regional offices and 150 field offices worldwide. The WHO was established on 7 April 1948. The first meeting of the World Health Assembly (WHA), the agency's governing body, took place on 24 July of that year. The WHO incorporated the assets, personnel, and duties of the League of Nations' Health Organization and the , including the International Classification of Diseases (ICD). Its work began in earnest in 1951 after a significant infusion of financial and technical resources. The WHO's mandate seeks and includes: working worldwide to promote health, keeping the world safe, and serve the vulnerable. It advocates that a billion more people should have: universal health care coverag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrology
Hydrology () is the scientific study of the movement, distribution, and management of water on Earth and other planets, including the water cycle, water resources, and environmental watershed sustainability. A practitioner of hydrology is called a hydrologist. Hydrologists are scientists studying earth or environmental science, civil or environmental engineering, and physical geography. Using various analytical methods and scientific techniques, they collect and analyze data to help solve water related problems such as environmental preservation, natural disasters, and water management. Hydrology subdivides into surface water hydrology, groundwater hydrology (hydrogeology), and marine hydrology. Domains of hydrology include hydrometeorology, surface hydrology, hydrogeology, drainage-basin management, and water quality, where water plays the central role. Oceanography and meteorology are not included because water is only one of many important aspects within those fields. H ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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