Posts Tagged "hydropower"

The Challenge of Sediment Management

Posted by on Jan 20, 2016 in All Posts, Featured Posts, Policy and Economics, Science | 0 comments

The Challenge of Sediment Management

Spread the News:ShareA new research study entitled “Ecosystem impacts of Alpine water intakes for hydropower: the challenge of sediment management” explores the effects of different hydropower capture techniques on human and ecosystem water needs. Rivers fed by glacial melt and snowmelt in Alpine regions serve as a critical resource for hydroelectric power production. However, the management systems used in hydroelectric systems heavily impact both river and sediment flow. This disruption, in turn, heavily, and often negatively, impacts downstream communities and ecosystems, which face consequences of habitat change, degradation, and temperature increases. The authors note that few policy solutions are currently available to reduce and manage these impacts, and call for fresh ideas to address them. The study, published in the latest January/February issue of Wiley Interdisciplinary Reviews: Water, reviews the three main types of water management techniques used in hydropower systems. Dams impound water behind barrages in a valley, while abstraction removes water from a ground source. Once abstracted, water is moved laterally (shifted nearby) or downstream (to a lower part of a river) in order to reach the hydroelectric plant. The article systematically examines how these different methods impact water and sediment flow of the river. Though previous work has studied the impact of different types of water management techniques on river flow, this study is the first of its kind to closely investigate the impact of water abstraction and transfer systems on sediment displacement, which, the study argues, “can significantly influence habitat, which in turn impacts ecosystems.” The disruption and transfer of sediments have important impacts on human and natural ecosystems because they interfere with what the researchers call the “the natural sediment ‘conveyor belt’” — the process of sediment transfer that is usually determined by natural processes such as erosion, abrasion, sorting, and deposition. Though rivers primarily transport water, they are also vital vessels of sediment transfer. Fine sediment particles enter the river as the water erodes the banks, or tiny fragments break off from rocks in the water. The river carries these particles downstream, allowing the larger ones to drop out—or be deposited—in places where currents slow down. Disruption of water and sediment flow puts Alpine ecosystems, whose flow regimes are a “key driver” of their physical habitat, at risk. Alpine habitats face risk of physical habitat change, degradation, temperature increases, and major changes to riparian vegetation. Previously inundated rivers may become dry. Such rapid changes in stream flow may leave Alpine fish not able to adapt quickly enough to sustain these alterations. Water abstraction may also “induce lower or higher nutrient levels, depending on the geology; increase electrical conductivity depending on the solute-richness; and/or increase pH.” In order to guarantee both human and ecosystem water needs and minimally disrupt natural sediment transfer processes, hydroelectric systems and water management systems must replicate as close to a natural flow regime as possible. However, attempts to mimic variables of water magnitude, frequency, duration, timing, and rate of charge of each river are unlikely to be met due to simple “constraints of hydroelectric production,” the researchers note. Natural river and sediment flows fluctuate seasonally, making them difficult to mimic because hydropower systems are designed to operate with steady, slow flows. These flows, in turn, rarely provide enough speed to carry larger particles, but also never slow enough to allow smaller particles to settle. The researchers offer several suggestions to reduce the impacts of sediment transfer on downstream ecological and human communities. They seem some promise in sediment management processes, such as reducing sediment flushing during flows, creating artificial sediment sinks, and finding ways to permanently accumulate remaining sediment into...

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Roundup: Droughts and Floods in the Future

Posted by on Nov 23, 2015 in All Posts, Featured Posts, Roundup, Uncategorized | 0 comments

Roundup: Droughts and Floods in the Future

Spread the News:Share15% Shrinkage for Tibet Glaciers “Glaciers on the Tibetan Plateau – the source of rivers such as the Brahmaputra – have shrunk by as much as 15 per cent, retreating by 8,000 square kilometres since 1980, according to a new Chinese government-backed study. The decades-long study conducted by the official Chinese Academy of Sciences (CAS) discovered that the perennial frozen earth on the Tibetan plateau had also shrunk by 16 per cent over the past 30 years.” Read more of the story here.   Nepali Communities in Fear of Glacial Melt Floods “Pemba Sherpa looks fearfully at the huge Imjha glacier lake which lies at an altitude of nearly 6,000 metres above sea level in the Everest region of eastern Nepal…His house in Chukung village is only a few kilometres from the rapidly growing lake.”   Read more of the story here.   Climate change: Melting glaciers bring energy uncertainty “Running 2,000 kilometres from east to west and comprising more than 60,000 square kilometres of ice, the Hindu Kush–Karakoram–Himalayan glaciers are a source of water for the quarter of the global population that lives in south Asia. Glaciers are natural stores and regulators of water supply to rivers, which, in turn, provide water for domestic and industrial consumption, energy generation and irrigation.” Read more of the story here. Spread the...

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Roundup: Swiss Blankets and Data, Participation in Tajikistan

Posted by on Sep 21, 2015 in All Posts, Featured Posts, News, Policy and Economics, Roundup, Science | 0 comments

Roundup: Swiss Blankets and Data, Participation in Tajikistan

Spread the News:ShareBlankets covering Swiss glacier to halt ice melt is a temporary fix “From a distance, the Rhone glacier seems perfect, but when seen closely, the surface is covered with white blankets for slowing down the melting of the rapidly retreating ice. The dusty, white fleece covers a huge area near the glacier’s edge. But there is a Swiss tourist attraction hidden under the blankets. It is a long and winding ice grotto with shiny blue walls and a leaky ceiling that has been carved into the ice here every year since 1870. While poking at a piece of cloth lying besides the way that leads toward the cave’s opening, David Volken, a glaciologist working with the Swiss environment ministry, said that for the last eight years, they have been covering the ice cave with such blankets to decrease the ice melt.” Click here to read more. A participatory method to enhance the collective ability to adapt to rapid glacier loss: the case of mountain communities in Tajikistan “A 2010 participatory case study in the Zerafshan Range, Tajikistan, disclosed a local lack of awareness of climate change and its consequences. We present a social learning method based on scenarios and visualization. The process exposed a remarkable potential for comprehensive adaptation, including in water harvesting, choice of crops and livestock, environmental enhancement, skills and conflict management. We recommend the approach as a model to promote local collective adaptive capacity development. The case study revealed high risks of massive out-migration from mountain villages if adaptation starts too late: countries with a high proportion of mountain agriculture might see significant losses of agricultural area, a reduction in food production and an increase in conflicts in areas where immigration occurs.” To read more about the study and its findings, click here. Influence of land use and climate change in glacial melt and hydrological process “Land use and climate change play a significant role in hydrological processes. This study assesses the impact of land use and climate change in a snow and glacier dominated high altitude watershed, located in the southwestern part of Switzerland…. Our study shows a decrease in the summer peak flow and an early start of the melt driven peak flow. The major change observed in this study is the rising period of the hydrograph, i.e. in May and June an early shift is observed in the discharge. Independent analysis from land use change and climate change shows that the peak flow reduction occurs as a result of land use change, but the peak flow together with the timing of peak flow occurrence is also influenced by climatic change. The combined effect suggests a reduction of peak flow and early melt driven streamflow in the future. Information obtained from this study can be useful for water managers, especially for the hydropower based energy production sector in the Rhone watershed.” To learn more, click here. Spread the...

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Glacier Conference in Bhutan Promotes Collaboration

Posted by on Apr 30, 2015 in Adaptation, All Posts, Featured Posts, News, Policy and Economics, Science | 0 comments

Glacier Conference in Bhutan Promotes Collaboration

Spread the News:ShareA recent conference in Bumthang, Bhutan, titled “International Glacier Symposium: How much do we know about the glaciers of the high Himalayas?” presented data on glaciers there and in neighboring countries. It traced the implications of this work for hydropower development and environmental management across the Himalayan region and led to concrete plans for future collaborations. The conference was held on 16-18 April in the Daphne Conference Hall at the site of the Ugyen Wangchuck Institute for Conservation and Environment (UWICE), the premier environmental organization in Bhutan.  It was sponsored by the Bhutan Foundation and the World Wildlife Fund. Over 60 researchers, students, government officials and NGO staff fromsou Bhutan, Nepal, India, the United States, Germany and Switzerland attended the conference. The conference hall was one of three buildings that opened on 16 April at UWICE; the others were the Centre for South Asia Forestry Studies and the Ugyen Wangchuck Museum for Ethnobiology. A member of the royal family, Her Royal Highness Ashi Chimi Yangzom Wangchuck, conducted the inauguration for the events, which included the participation of a number of officials, lamas and monks, as well as foreign guests. The director of UWICE, Dr. Nawang Norbu, opened the conference with a welcoming address. He summarized the conference,  saying that “it defines the next pressing questions which need to be addressed … with regards to glaciers and science. The symposium is expected to contribute significantly towards the understanding of glaciers,  enhancing a fruitful collaboration with the regional partners.” Dr. Norbu was followed by two distinguished speakers.  Lyonpo Yeshey Dorji, the Minister of Agriculture and Forests in Bhutan, spoke of the importance of glaciers for hydropower and flood risks in Bhutan,  and Shri Harbans Singh, the Director General of the Geological Survey of India, discussed glacier monitoring methods in light of the contribution of glaciers to the flow of the major rivers of South Asia. They both pointed to the importance of advancing research for addressing sustainable development needs.  A keynote address, which I presented, raised the issue of valuation of glaciers—the means by which individuals and organizations assess the importance of the positive contributions of water resources,  the negative impacts of glacier-related hazards, and the cultural and religious significance of mountain landscapes. From this basis, the conference moved to a series of talks that addressed the current state of knowledge of Himalayan glaciers. Phuntsho Tshering of the Department of Geology and Mines reported on the first decade of mass balance research in Bhutan, presenting the measurements that document glacier shrinkage. Two researchers reported on measurements of a number of glaciers in India. They indicated a general pattern of retreat, modulated by a number of factors such as elevation, orientation, size, and location on an east-west gradient.  Deo Raj Gurung of ICIMOD in Nepal reported on satellite data that allowed him to trace the shrinkage snow cover in recent decades in the Hindu Kush, just west of the Himalayas. Richard Forster of the University of Utah gave a more methodological talk. He described how remote sensing that uses microwave radiation can identify small ice features on the surface of glaciers and track them as they move, allowing for the first time measurement of the velocity of glacier movement. Extending these glacier measurement studies, which report only on recent years or decades, were two other papers which used proxy measurements to assess climate in past centuries.  Ed Cook of Columbia University used tree ring data from Bhutan and portions of neighboring countries. These offer precise annual records from which summer temperature patterns can be assessed. Cook traced warmer and cooler periods back to...

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Climate Change Brings Global Energy Concerns

Posted by on Feb 18, 2015 in Adaptation, All Posts, Communities, Policy and Economics | 0 comments

Climate Change Brings Global Energy Concerns

Spread the News:ShareGlobal reliance on hydroelectric energy production has only increased in the 21st century, even as our supply of hydropower has become increasingly uncertain due to climate change impacts, including glacial retreat. South Asia is a clear example: due to the high cost and political risks of importing fuels like oil or coal, countries in this region have increasingly turned to hydroelectric power for domestic energy production. But changes to the Himalayan hydro-ecosystem could severely disrupt future hydroelectric development in South Asia. Today, large regional electrical grids feed most global energy demand. To maintain constant supply and meet demand as efficiently as possible, different “tiers” of power plants tend to work together. “Base load” power plants, such as nuclear and coal generators, are most efficient when providing a constant supply of energy around the clock, as opposed to in short bursts to meet peak demand, and so form the backbone of most electric grids. “Load following” power plants are used to adapt to short-term changes in demand, typically shutting down at night or early morning. Examples include natural gas or diesel and renewable power plants. “Peaking power” plants can start and stop very quickly but are far less efficient than base load plants at longer timescales and are more expensive to run than load following plants. They typically come online for only a few hours a day to meet peaks in energy demand. Diesel and gasoline internal combustion engines are examples. Hydroelectric generators can theoretically be used to fill any of these roles, depending upon the availability of water, the size of the reservoir, and the installed capacity. For this reason variations in hydro-ecosystems have a large impact on the energy potential available to such generators. If a hydroelectric plant is supplying base load energy, low stream flow can lead to power outages. If such a plant is used to supply peak needs, declines in water supplies at the wrong times can cause voltage drops or brownouts. Conversely, if the reservoir is too full due to heavy rain or snowmelt, spillways have to be opened and the energy often cannot be used at all. For these reasons hydroelectric plants are most commonly used as load following plants. Some even pump water back up river into reservoirs as a form of energy storage if production is high when demand is low. In the Himalayas, hydropower is at grave risk, and yet there is virtually no supplementary base load power available, and little ability to purchase energy from other sources. As Himalayan glaciers melt at unprecedented rates, springtime stream flows have become more intense and unpredictable, while the risks of glacial lake outburst floods and landslides are growing. The severe inconsistency of the water supply could even cause hydroelectric projects to fail, flooding downstream communities. Ultimately, investments in hydroelectric power in the region may be disproportionate to the amount of energy that these plants will realistically be able to produce, given the ecosystem risks. Although South Asia is in a notably precarious position, such concerns are not uniquely Himalayan.  In fact, according to a study by Schaefli et al., the net effect of global warming in Switzerland will be to noticeably reduce hydroelectric production, which is a serious problem for a country where 75% of electricity comes from hydroelectric power. Another 2014 study on Swiss hydropower by Ludovic Gaudard et al. has warned that increased water scarcity may lead to competition for water uses, further limiting water available for energy production. As such, the country has been taking measures to insure energy resilience, managing its hydro projects more closely and investing in other forms of renewable energy. According to the results of a project by the Swiss Sustainable Water Management National Research Programme, more careful water management practices could make up for increasing stream flow uncertainty. In the US Pacific Northwest, scientists are advocating...

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