Tag Archives: dams and floods

Tying Up the Nile River

Blue Nile Falls. Image from wikipedia
Since Ethiopia announced its plan to build the Grand Ethiopian Renaissance Dam, it has inspired threats of sabotage from Egypt, which sits downstream and relies on the Nile for electricity, farming and drinking water. Egypt claims that it is entitled to a certain proportion of the Nile’s water based on colonial-era treaties….

By 2050 around a billion people will live in the countries through which the Nile and its tributaries flow. That alone will put enormous stress on the water supply. But according to a study by Mohamed Siam and Elfatih Eltahir of MIT, potential changes to the river’s flow, resulting from climate change, may add to the strain. Messrs Siam and Eltahir conclude that on current trends the annual flow could increase, on average, by up to 15%. That may seem like a good thing, but it could also grow more variable, by 50%. In other words, there would be more (and worse) floods and droughts.

There is, of course, uncertainty in the projections, not least because differing global climate models give different numbers. But the idea that the flow of the Nile is likely to become more variable is lent credibility, the authors argue, by the fact that trends over decades seem to agree with them, and by consideration of the effects of El Niños. 

More storage capacity will be needed to smooth out the Nile’s flow. But unlike Egypt’s large Aswan Dam, which was built with storage in mind, the new Ethiopian one is designed for electricity production. Once water starts gushing through its turbines, it is expected to produce over 6,000 megawatts of power. It is unclear, though, if the structure has the necessary flexibility to meet downstream demands in periods of prolonged drought.

The talks between the three countries, Ethiopia, Sudan and Egypt, seem to be glossing over the potential effects of climate change. “Nowhere in the world are two such large dams on the same river operated without close co-ordination,” says another study from MIT. But so far co-operation is in short supply. The latest round of talks has been postponed. Even the methodology of impact studies is cause for wrangling.

Excerpts from: Climate Change and the Nile: Flood and Famine, Economist, Aug. 5, 2017

Dams and Drought: the Amazon

The city of Itaituba on the banks of the Tapajós River. Image from wikipedia

The São Luiz do Tapajós (SLT) project… would dam one of the last big unobstructed tributaries of the Amazon. The project would provide about a third of the hydropower that Brazil plans for the forthcoming decade, but it would also flood 376 square km (145 square miles) of land where the Munduruku hunt, fish and farm. “The Tapajós valley is our supermarket, our church, our office, our school, our home, our life,” explained Mr Kabá.

The tussle over the Tapajós dam is part of a bigger fight about Brazil’s energy future. SLT is an example of a new sort of hydropower project, which floods a smaller area than traditional dams and therefore ought to cause less disruption and environmental damage. The massive Itaipu dam on the border with Paraguay inundated an area nearly four times as large. But critics of hydropower say “run of river” projects like SLT, which use a river’s natural flow to turn turbines, do not work as well as advertised. Though less destructive than conventional dams, which require bigger reservoirs, they still provoke opposition from people like the Munduruku. Other energy sources, such as gas and wind, are becoming more competitive. Brazil has “an opportunity” to rethink its energy policies, says Paulo Pedrosa, an energy official.

Hydropower has long been Brazil’s main way of generating electricity. Most forecasts suggest it will remain so. The government intends to build more than 30 dams in the Amazon over the next three decades. 

Climate change may worsen the problem. Some climate models predict that river flows in large parts of the Amazon will fall by 30% in coming decades. Deforestation is delaying the onset of the rainy season in some areas by six days a decade, according to research published in Global Change Biology, a journal.   Drought can be expensive. In 2014 power from conventional dams dipped because of a dry spell, forcing electricity companies to buy from gas- and coal-powered generators at high spot prices. The risk of such fluctuations rises with run-of-river dams. Carlos Nobre, a former chief of research at the ministry of science, technology and innovation, thinks more frequent droughts will make future hydropower projects in the Amazon unprofitable.

Brazil’s potential for solar and wind energy is among the highest in the world. The government has promoted them with lavish tax breaks. In the blustery north-east, wind power overtook hydropower this year; wind turbines now generate 36% of the region’s electricity, up from 22% in 2015. The Energy Research Company, a firm linked to the energy ministry, expects renewable generating capacity apart from hydropower to double by 2024.

Generators fuelled by natural gas have been hurt by the subsidies lavished on renewable energy. But, though less climate-friendly than hydropower, they are beginning to compete with it as a source of steady baseload electricity. Brazil now produces gas in abundance as a by-product of pumping oil from its offshore wells. Its marginal cost of production is nearly zero. The future of baseload energy is “hydro-thermal”, rather than hydro alone, says Adriano Pires of the Brazilian Infrastructure Centre, a think-tank in Rio de Janeiro.

Excerpts from Dams in the Amazon: Not in my valley, Economist,  Nov. 5, 2016

The Most Dangerous Dam in the World

Mosul Dam chute spillway. image from wikipedia

Sensors installed by American army engineers in December 2015 show widening fissures in the fragile gypsum base underneath the Mosul dam,  though no one can predict when a breach might occur….The Iraqi government has now contracted with the Trevi Group, an Italian firm, which it hopes will offer a more advanced and permanent method of plugging cavities in the stone base than the constant maintenance it has required for the past 30 years. That maintenance came to an abrupt halt after IS seized the dam in August 2014, and has continued only intermittently after it was seized back three weeks later. Essential equipment went missing then, and half its staff decided not to return to work.

One study says that if the dam collapses, Mosul would be submerged within hours. Another warns that half a million Iraqis could be killed by floodwaters, and more than a million forced from their homes. Disease and looting as the floodwaters raced through Baiji, Tikrit, Samarra and even parts of Baghdad would complete that dreadful scenario.

The dam was built by an Italian-German consortium and started operating in 1986. Because of the high proportion of gypsum in the area, the construction included a grouting tunnel to allow almost constant injection of cement and drilling mud into crevices in the base that are widened by the water flowing through them. America’s Army Corps of Engineers warned in 2005 that the “extraordinary engineering measures” needed to maintain its structural integrity made the structure potentially the most dangerous in the world.*** But taking the dam out of commission is not an attractive option. Emptying the reservoir would leave Iraqis seriously short of drinking and unpolluted irrigation water in the summer.

Excerpts from The Mosul dam: A watery time-bomb, Economist, Feb. 13, 2016, at 42

***  The dam was constructed on a foundation of water soluble gypsum!!! More than 50,000 tonnes  of material have been injected into the dam since leaks began forming shortly after the reservoir was filled in 1986, and 24 machines currently continuously pump grout into the dam base. Between 1992 and 1998 four sinkholes formed downstream of the dam and a fifth sinkhole developed east of the dam in February 2003 which was filled several times. In August 2005 another sinkhole developed to the east (Wikipedia).

The Price of Dams: Vietnam

Ya Ly dam spillway,Vietnam

Hydropower has boomed in Vietnam over the past decade and now generates more than a third of the country’s electricity. In 2013 the National Assembly reported that 268 hydropower projects were up and running, with a further 205 projects expected to be generating by 2017. They are helping to meet a national demand for energy that the authorities forecast will treble between 2010 and 2020. Other power sources are less promising, at least in the short run. A plan to build several nuclear reactors by 2030 is behind schedule, for example. And Vietnam’s coal reserves, mostly in the north, are not easy to get at.

Yet the hydropower boom comes at a price. Rivers and old-growth forests have been ravaged, and tens of thousands of villagers, often from ethnic minorities, displaced. Many have been resettled on poor ground. Those who have stayed are at risk of flash floods caused by faulty dam technology and inadequate oversight. Green Innovation and Development Centre, an environmental group in the capital, Hanoi, says shoddy dam construction is the norm, and developers ignore the question of whether their projects could trigger earthquakes…

Many hydro-electric companies are owned by or affiliated with Electricity Vietnam (EVN), the loss-making state power monopoly. Because hydropower is Vietnam’s cheapest source of electricity, EVN resists investing in measures such as dam-safety assessments that would further erode its financial position. As it is, even though environmental-impact assessments for hydropower projects are required, they are never published, according to the United Nations Development Programme….. Hydropower companies want to keep their mountain reservoirs as full as possible in order to generate as much electricity as Vietnam’s rivers allow. But that narrow focus can deprive farmers of irrigation in the dry season. And when heavy rains come in the summer and autumn, floodwaters cascade over the dam walls with little or no warning.

Hydropower in Vietnam: Full to bursting, Economist, Jan.10, 2015, at 35

The Belo Monte Hydroelectric Dam in Brazil: the need for a social pact

These dams [like the Belo Monte] harness the natural flow of the river to drive the turbines, so they do not require large reservoirs, and as a result, less land needs to be flooded – which means less of an impact on the environment and surrounding communities. However, it also means that during dry spells, they do not have the water reserves needed to continue generating electricity at a reasonable capacity.   “We are increasing the installed generating capacity, but water storage capacity has not grown since the 1980s,” which is a cause for concern, said Nelson Hubner, general director of the Brazilian Electricity Regulatory Agency.  The “stored energy” represented by the country’s reservoirs has not kept up with demand, which will make it impossible to maintain the necessary supply of hydroelectricity during a drought year, warned Hubner at the Second Hydropower Summit Latin America, held May 9-10 in São Paulo.  The summit, organised by Business News Americas (BNamericas), a business and economy news service based in Santiago, Chile, brought together dozens of executives from both public and private companies in the sector. Many were highly critical of the model chosen for the country’s new hydroelectric power plants, which they believe will result in greater energy insecurity in Brazil.  “Future generations will demand compensation for the fact that biodiversity was decreased and reservoirs were not created” in current hydropower projects, predicted Jose Marques Filho, assistant director of environment and corporate citizenship at Companhia Paranaense de Energia, a power company run by the government of the southern Brazilian state of Paraná.

By renouncing the use of this “long-life battery”, as another summit participant described reservoirs, Brazil will need to build more fossil fuel-powered thermoelectric plants, which are more polluting but “are not under attack from environmentalists,” complained the hydroelectric dam constructors and their supporters.

Construction began in 2011 on the Belo Monte hydroelectric dam on the Xingú River in Brazil’s Amazon basin. A total of 516 sq km of land will be flooded for the project, but this is only 42 percent of the area that would have been flooded for the reservoir planned in the original version of the project, drawn up in the 1980s.  However, because of this smaller reservoir, the plant will only reach its total generation capacity of 11,233 megawatts during the brief rainy season when the river is swollen to its highest level. During dry spells, output will decrease significantly, since the flow of the Xingú can drop from 30,000 cubic metres a second in March and April to less than 500 cubic meters in a dry month like October.

“We have to get used to hydroelectric dams without large reservoirs because the environment demands it,” said Mauricio Tolmasquim, president of the Energy Research Corporation, which provides advisory services to the Ministry of Mines and Energy. The Amazon region, where most of Brazil’s hydropower potential is concentrated, is primarily flat, which means there are few sites where water can be accumulated and stored without flooding large areas of forest, he explained.  Belo Monte, located at the end of a canyon, is one of these sites. A large reservoir there would flood two indigenous territories which are home to over 200 people. “That was a determining factor” for modifying its design and adopting run-of-the-river technology, Tolmasquim told Tierramérica.  This decision, however, did not spare Belo Monte from becoming the target of the most widespread opposition ever against an energy project in Brazil, with environmentalists, civil society activists, indigenous communities and even local soap opera stars and international celebrities joining forces to denounce its environmental and social impacts.

Tapping the rivers of the Amazon basin for energy production should begin “with smaller hydroelectric dams, with an output of around 500 megawatts,” said Goldemberg, a University of São Paulo professor who has headed a number of state-owned energy companies and was the national secretary of environment when the city of Rio de Janeiro hosted the Earth Summit in 1992…..

The conflicts that sometimes halt the construction of hydropower plants in Brazil pit a small local population of perhaps a few thousand people against a million people who will benefit from the electricity produced, but are far away and geographically scattered, commented Goldemberg.  What are needed are “good projects” that are transparent and attend to the potential social and environmental impacts. In addition, it is up to the government to “mediate and explain” to settle these conflicts, given the disproportionate ratio of opponents to beneficiaries of roughly “one per one hundred,” he said.

There are much more complex situations in Asia, where enormous numbers of people are affected because of the population density of countries like India, he added. Goldemberg learned a good deal about numerous cases like these as a member of the World Commission on Dams, which produced a report in 2000 detailing the damages caused by these projects and the requirements for their construction.

For those in the hydroelectric dam construction industry, the issue of the environment has become an obstacle to the expansion of hydropower in Brazil.  In the meantime, the wind power industry has experienced a significant boost, largely because their competitors in the hydropower sector have been unable to obtain permits from the environmental authorities for years, he observed.  According to Marques Filho of the Companhia Paranaense de Energia, overcoming this impasse will require a “social pact”, based on “a dialogue among all the stakeholders” that cannot be limited to environmentalists on one side and hydroelectric dam constructors on the other.

Excerpts, Mario Osava, Belo Monte Dam Hit by Friendly Fire, Inter Press Service, May 22, 2012