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Friday, 23 September 2011

World Rivers Day - September 26


    The world's rivers are in crisis, according to in Nature. The study combines, for the first time, water security and biodiversity for all of the world's rivers, many of which are severely degraded.

World's Major Rivers

Rivers worldwide in peril: society treats symptoms, ignores causes


Water Resource Development

* Dams alter downstream movement of sediment and nutrients, and block fish migrations.
* Water withdrawals reduce the flow in riversn leaving them completely dry in some cases.
* Water Scarcity can diminsh human quality of life and limit food production.
* Disrupting natural cycle of water flow decreases floodplain fertility and eliminates fish breeding grounds.


Biotic Factors

* Introduced species can transform river habitats and biological communities.
* Fishing pressure can remove large fish from rivers, leaving impoverished food webs.
* Aquaculture can pollute rivers with nutrients and chemicals, and serve as source of invasive species.


Pollution

* Nutrients such as nitrogen and phosphorus can encourage nuisance algal blooms.
* Mercury, pecticides, acids, and salts can be toxic to river animals and plants.
* Organic Material can lead to oxygen depletion of water sediments can  coat river bottoms and block light.
* Industrial discharges can increase water temperatures.


Catchment Disturbance

*Conversion of forests and grasslands to agricultural fields change water flows and riveside habitat.
* Roads, buildings and other man-made surfaces block rainfall from entering groundwater, and pollute runoff.
* Lifestock trample riverside habitat and river channels, and introduce harmful microbes
* Disconnecting wetlands and floodplains from rivers reduces flood protection.


     The Importance of River Water The world’s lakes and flowing rivers constitute just one percent of the planet’s water. The fresh water in rivers is vital to all land base life. But population pressures are putting major water waste under stress. Rivers provide drinking water and water for agricultural purposes and since the beginning of human civilization, rivers have been used for transport and cities have grown on their banks.
     Rivers, now an integral part of the water cycle where fresh water, falling as rain or snow flows to the oceans to be evaporated by warmth from the sun forming clouds which release rain. All plant and animal life depends on this cycle. Africa’s River Nile is the longest river in the world. Since ancient’s times, the Nile has been a lifeline for the people and animals along its 6,800 kilometer length. Ten countries shares the Nile but the Nile water agreement of 1929 granted Egypt, the lion share of the Nile’s waters.
     The treaty was signed when 67 year old Banabus Equatus parents with children. His one acre farm near Canyons Lake Victoria has been in the family for generations. He is the only one in his area that defies the water treaty and irrigated his land. The treaty has been criticized by east African countries as a colonial relic that impedes development in upstream countries. Some says the treaty is stopping him from expanding his farm. Lake Victoria is the source of the White Nile, the longest branch of the Nile. It’s the world’s largest tropical lake and is an important transport hub for Uganda, Tanzania and Kenya. Uganda, Ruwanda, Verandi, Kenya, Tanzania, Ethiopia, the Congo, Sudan and Egypt all rely on the Nile for agriculture. The Egyptian capital Cairo sits on the banks of the Nile and because of the treaty, it convict any upstream irrigation plans that could threatened the Nile’s levels. 
    Over 95% of Egypt’s water comes from the river and most Egyptian’s lived in the third tile Nile of Valley though it makes up only 4% of Egypt’s available land. The country’s population is growing to the Egypt’s need for water will continue to increase. But many of the sub-Saharan countries have been pushing for what they say would be a fairer use of the Nile’s waters. The fair sharing of the waters from international water waste is a growing issue around the world. In fact that Egypt at the end of Nile has so much control has more to do with international politics in the early 20th century when the treaty was drafted. Every year, the Nile floods bringing with it replenishing nutrients that act as a natural fertilizer. 
    In 2004, an international expedition sits off and navigates the White Nile from source to sea for the first time in history. The five person teams sponsored by KIA international are from Ireland, New Zealand, and South Africa. In some places, the settle the Nile expedition needed help from the local people to carry their specially constructed drafts around the difficult stretches of the upper river. They started from Bujagali falls in Jinja Uganda, to follow the river from Lake Victoria through Sudan and finally to Egypt and the Mediterranean. After some particularly turbulent stretches of the Nile and Uganda’s falls Natural Park retained to have timeout to ponder the dangers ahead. One of the biggest problems in this path of the Nile with a hippos and elephants would enjoy bathing in the river. Wherever the cruise stop, they drew crowds of curious own lookers. One reason for the expedition was to promote harmony amongst the people of the Nile. The team was equipped with two five meter self bailing inflatable rafts. As the Nile broad and then slowed, the rafters had to start paddling. 
    To previous expeditions using collapsible canoes were force to carry their craft for large path of the journey. Four months later, after coming to deserts, for war zones and jungles, the two craft were motoring through the Nile’s biggest city Cairo. Great explorers of the 19th century had struggled to map the world’s longest river. The rigid wooden boats could not cope with the turbulent waters of the apple White Nile. But other places, the river disappears into broad mashed lands. To settle the Nile expedition had come through about 46 of particularly set of treacherous rapids at one stage loosing a pedal to the jaws of a crocodile. All 16 members had been living in east Africa for at least five years. Between them, they could boast an incredible 50 years of white water and expedition experienced. Soon after the Nile passes through the Egyptian capital, it breaks into distributaries that found out which reach delta region. 
    The grip would emerge into the Mediterranean at Rosetta. The city that gave its name to the Rosetta stone had led to the deciphering of hieroglyphics. The Nile is unusual and its last tributary joined at halfway along its length in the Sudan. The Nile at Cairo is actually a smaller river than it is in the Sudan. The realtors described Egypt as the gift of the Nile because of this great river, the early inhabitants of Egypt were able to settle and establish a width base agriculture that led to the development of the ancient Egyptian civilization. Despite 8,000 years of human activity on its banks, they settle the Nile expedition was the first to navigate the Nile entire length. Since the Roman Empire, people have been seeking the headwaters of the Nile back until the 19th century expeditions have been unable to penetrate the sued marshlands in the Sudan. After a brief stay in Cairo, the rafters finished the last 200 kilometers stretch to Rosetta in the Mediterranean in around ten days with a complete voyage along the Nile had taken 18 weeks. A film about their journey called the longest river was released the following year.





Map of Danube and Rhine River

    The Rivers helped the Roman Empire in the same way they hurt the Empire.
     Rivers were the natural 'highways' in ancient times. Boats could carry products for trade back and forth along these natural routes. Settlements, based primarily on trade, would often spring up along river banks where a natural setting existed for the construction of docks to on/off-load ships.
    Unfortunately rivers were also highways which could be used to transport (both friendly and unfriendly) troops intent on doing war. The mountains were important as they provided a natural fortress wall complete with surveillance 'towers'.


Map of the Colorado (USA-Mexico), Columbia (USA-Canada), Nelson-Saskatchewan (USA-Canada), and Mississippi (USA) River
     
    The North American continent contains the world's greatest inland waterway system. The Mississippi River rises in northern Minnesota and flows 2,348 miles (3,778 kilometers) down the center of the United States to the Gulf of Mexico. The Missouri River, formed by the junction of three rivers in southern Montana, runs 2,466 miles (3,968 kilometers) before it joins the Mississippi just north of St. Louis, Missouri. The Ohio River, formed by the union of two rivers at Pittsburgh, Pennsylvania, flows 975 miles (1,569 kilometers) before emptying into the Mississippi at Cairo, Illinois. The Mississippi, with all of its tributaries, drains 1,234,700 square miles (3,197,900 square kilometers) from all or part of 31 states in the United States. From the provinces of Alberta and Saskatchewan in Canada, the Mississippi drains about 13,000 square miles (33,670 square kilometers). 

     Other chief rivers in North America include the Yukon (Alaska and Canada); Mackenzie, Nelson, and Saskatchewan (Canada); Columbia and St. Lawrence (Canada and U.S.); Colorado, Delaware, and Susquehanna (U.S.); and Rio Grande (U.S. and Mexico).
     North America contains more lakes than any other continent. Dominant lakes include Great Bear, Great Slave, and Winnipeg (Canada); the Great Lakes (Canada and U.S.); Great Salt Lake (U.S.); Chapala (Mexico); and Nicaragua (Nicaragua). The Great Lakes, a chain of five lakes, are Superior, Michigan, Huron, Erie, and Ontario. Superior, northernmost and westernmost of the five, is the largest lake in North America and the largest body of freshwater in the world. Stretching 350 miles (560 kilometers) long, the lake covers about 31,820 square miles (82,410 square kilometers). It has a maximum depth of 1,302 feet (397 meters).


Map of the Amazon and La Plata (Parana) River

    The Plata Basin is structured along the major population and production demographic group in South America. With almost 130 million inhabitants, some 50 large cities and an economy that represents 70% of GDP per capita of the five countries, is of major economic and social importance. But according to a recent report by Unesco, “the increase of poverty remains the most important social issue facing the countries that comprise it.”
    The lower income sector, especially poor people, has a high dependence on natural resources, thus its deterioration provokes losses in household income  and diminish of opportunities. To mention only two examples, overfishing at unsustainable rates for export causes a drop of fishery resources in the lower Parana along with negative social impacts, the expansion of clearings and large-scale monocultures impact on family farming and rural emigration aggravating overcrowding in marginal areas of big cities.


    Many of Asia's major rivers begin in the Himalaya Mountains, the largest being the Yangtze. The Brahmaputra River, the world's fourth largest, flows through China, India, and Bangladesh. The Ganges River, the fifth largest, flows 1,560 miles from the Himalayas to the Bay of Bengal. India and China have had numerous disputes over China's failure to warn those downstream of floods in Tibet, which have taken lives along the Brahmaputra. In Southeast Asia, the Mekong River flows through China, Myanmar, Laos, Thailand, Cambodia, and Vietnam, where the lower Mekong basin is the world's most productive fishery. There are concerns over China's plans for hydro-power diversions in the headwaters of the Ganges, Brahmaputra, and Mekong Rivers, which would affect Pakistan, India, Bangladesh, Myanmar, Thailand, Laos, Cambodia, and Vietnam.


Map of Jordan and Tigris- Euphrates Rivers

    Despite the great size of the Middle East, there are only three rivers that can be classified as large by world standards-the Nile, the Euphrates, and the Tigris. The watersheds of both the Euphrates and the Tigris are situated within the Middle East, predominantly in the countries of Turkey, Syria, and Iraq .
    The Euphrates, which is the longest inter-state river in western Asia, has been developed since 4000 B.C. Several ancient civilizations in Mesopotamia were supported by basin irrigation from the Tigris and Euphrates Rivers. Owing to the extremely arid climate, however, the farm lands on the Mesopotamian alluvials have suffered from salt accumulation and waterlogging problems since 2400 B.C., during the Sumerian age. This ancient civilization disappeared with the abandonment of irrigation-canal systems. The washing out of accumulated salts, or leaching as it is called, can be carried out only with an efficient

Map of the Nile River

The River Nile is about 6,670 km (4,160 miles) in length and is the longest river in Africa and in the world. Although it is generally associated with Egypt, only 22% of the Nile’s course runs through Egypt.
In Egypt, the River Nile creates a fertile green valley across the desert. It was by the banks of the river that one of the oldest civilizations in the world began. The ancient Egyptians lived and farmed along the Nile, using the soil to produce food for themselves and their animals.



Map of the Murray Darling River

The three longest rivers in Australia all run through the Murray-Darling Basin. These are:
The Basin has a big variety of climatic conditions and its highly diverse landscapes range from sub-tropical conditions in the far north, cool humid eastern uplands, high alpine country of the Snowy Mountains, the temperate south-east, to the hot and dry semi-arid and arid western plains.



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