June 24, 2012

Central pivot irrigation is a form of overhead sprinkler irrigation consisting of several segments of pipe (usually galvanized steel or aluminum) joined together and supported by trusses, mounted on wheeled towers with sprinklers positioned along its length. The machine moves in a circular pattern and is fed with water from the pivot point at the center of the circle. The outside set of wheels sets the master pace for the rotation (typically once every three days). The inner sets of wheels are mounted at hubs between two segments and use angle sensors to detect when the bend at the joint exceeds a certain threshold, and thus, the wheels should be rotated to keep the segments aligned. Center pivots are typically less than 500 meters (1640 feet) in length (circle radius) with the most common size being the standard 1/4 mile (400 m) machine. To achieve uniform application, center pivots require an even emitter flow rate across the radius of the machine. Since the outer-most spans (or towers) travel farther in a given time frame than the inner most spans nozzle sizes are smallest at the inner spans and increase with distance from the pivot point.

Most center pivot systems now have drops hanging from a u-shaped pipe called a gooseneck attached at the top of the pipe with sprinkler heads that are positioned a few feet (at most) above the crop, thus limiting evaporative losses and wind drift. There are many different nozzle configurations available including static plate, moving plate and part circle. Pressure regulators are typically installed upstream of each nozzle to ensure each is operating at the correct design pressure. Drops can also be used with drag hoses or bubblers that deposit the water directly on the ground between crops. This type of system is known as LEPA (Low Energy Precision Application) and is often associated with the construction of small dams along the furrow length (termed furrow diking/dyking). Crops may be planted in straight rows or are sometimes planted in circles to conform to the travel of the center pivot.

(Source: Wikipedia)

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FILED UNDER: Agriculture Water Capitalism 
April 18, 2012
guardian: Photograph: Marizilda Cruppe/Greenpeace The controversial Belo Monte dam and hydropower plant in the Amazon - a gallery of its construction The Belo Monte would be the third largest dam in the world, and the second largest in Brazil. It is expected to submerge as much as 400,000 hectares and could displace an estimated 20,000 people

guardian:

Photograph: Marizilda Cruppe/Greenpeace

The controversial Belo Monte dam and hydropower plant in the Amazon - a gallery of its construction

The Belo Monte would be the third largest dam in the world, and the second largest in Brazil. It is expected to submerge as much as 400,000 hectares and could displace an estimated 20,000 people

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FILED UNDER: Water Brazil Capitalism 
April 4, 2012
Nepal clears China plan for $1.6 bln hydroelectric dam | Reuters The project, set to be completed in 2019, is expected to ease the crippling power shortage in Nepal whose economy is still emerging from a decade-long civil war - conflict that scared away investors and slowed infrastructure projects. Aid-dependent Nepal, with 900 megawatt of electricity shortage, is one of the world’s 10 poorest countries where tourism and hydropower are two key areas in which the government is trying to attract foreign investment.

Nepal clears China plan for $1.6 bln hydroelectric dam | Reuters

The project, set to be completed in 2019, is expected to ease the crippling power shortage in Nepal whose economy is still emerging from a decade-long civil war - conflict that scared away investors and slowed infrastructure projects.

Aid-dependent Nepal, with 900 megawatt of electricity shortage, is one of the world’s 10 poorest countries where tourism and hydropower are two key areas in which the government is trying to attract foreign investment.

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FILED UNDER: Capitalism News Clipping Water Nepal China 
March 30, 2012
Transnational Institute | The Global Water Grab: A Primer

Water grabbing is not a new phenomenon and has much in common with earlier resource grabs and what has been called the “enclosures of the commons.” The new dimension of contemporary water grabbing is that the mechanisms for appropriating and converting water resources into private goods are much more advanced and increasingly globalised, subject to international laws on foreign investment and trade. There is thus a real concern that a new generation of ‘Mulhollands’, the early 20th Century Los Angeles official who made water grabbing infamous, will profit from this scenario to the detriment of local communities and ecosystems, and at a scale that has not been seen before. In the context of a ‘global water crisis’, where 700 million people in 43 countries live below the water-stress threshold of 1,700 cubic metres per person, there is an urgent need to put an end to the global water grab.

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FILED UNDER: Agriculture Capitalism Water Africa Latin America 
March 25, 2012

centerforinvestigativereporting:

“Nearly 1,000 public water systems in Texas restricted water last year. Even now, after some winter rains, 17 systems are projected to run out of water in six months or less. The 2011 drought was the most intense one-year drought in Texas since at least 1895, when statewide weather records began. Losses reached $10 billion in crops, livestock and timber.” - Hari Sreenivasan in the PBS NewsHour segment (above) “Texas Towns Run Out of Water as Drought Takes its Toll.”

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FILED UNDER: Water News Clipping Agriculture 
March 24, 2012
Report: Water shortages increasingly will offer weapon for states, terror groups - The Washington Post

The assessment is drawn from a classified National Intelligence Estimate distributed to policymakers in October. Although the unclassified version does not mention problems in specific countries, it describes “strategically important water basins” tied to rivers in several regions. These include the Nile, which runs through 10 countries in central and northeastern Africa before traveling through Egypt into the Mediterranean Sea; the Tigris-Euphrates in Turkey, Syria and Iraq; the Jordan, long the subject of dispute among Israel, Jordan and the Palestinians; and the Indus, whose catchment area includes Afghanistan, Pakistan, India and Tibet.

“As water problems become more acute, the likelihood . . . is that states will use them as leverage,” said a senior U.S. intelligence official who briefed reporters on the condition of anonymity. As the midpoint of the century nears, he said, there is an increasing likelihood that water will be “potentially used as a weapon, where one state denies access to another.”

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FILED UNDER: Africa Agriculture Capitalism News Clipping Water Nile River 
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