Tag Archives: rivers

Salmon and hydropower can both thrive

FOR IMMEDIATE RELEASE Scientists produce handbook that shows how better river management can mean more breeding success for migratory fish and more electricity from a vital source of renewable energy LONDON, 13 October – Hydropower can dramatically alter rivers and destroy the habitat of migratory species such as salmon, but now scientists have shown that it is perfectly possible for rivers to produce more fish and more electricity at the same time. After years of experience with hydro schemes in their own country, Norwegian scientists have produced a handbook to assist river engineers and to explain how to protect vulnerable species while exploiting rivers for renewable energy. The Centre for Environmental Design of Renewable Energy (CEDREN) believes that by understanding the needs of migratory fish and controlling the flow of the river to accommodate their lifestyle, the breeding success can be improved. At the same time, by adapting and improving the turbine capacity and making it more flexible, more energy can be produced. While the handbook is based on experience in Norway, the same principles can be applied to many rivers in mountainous areas that have salmon or other migratory fish. Some of the ideas might also apply to fast-flowing rivers in places such as the Himalayas, the European Alps, the Rockies in North America, and the Andes in South America. There is resistance in many of these places to hydropower because it can cause drastic alteration to natural rivers and destroy their wildlife. As a result, there is still a large untapped potential for hydropower schemes in some regions.

Cheap and reliable

The handbook is intended as a blueprint to help engineers and environmentalists to work together to improve the habitat for wildlife, while extracting much-needed electricity from water power to help combat climate change. Hydropower is one of the cheapest and most reliable of renewables. As far as salmon rivers are concerned, the handbook says the first task is to identify current problems that limit salmon production in rivers. These include lack of spawning grounds or shelter, low water periods, or periods of disadvantageous water temperature. Looking at the existing or potential hydropower, engineers need to work out operating strategies for the power stations to avoid interfering with the salmon. These could include ideas such as transferring water from neighbouring rivers to improve flow at critical times, and increasing the capacity of turbines and waterways to make operation more flexible. How the available water in the river is used is critical. Water flow to ensure environmental quality and water releases at different times of the year need to be closely regulated. To achieve this, a flexible “water bank” will be required to ensure a good supply of water when needed. There also needs to be a smooth transition between high and low water flows, with some water being saved for critical periods. Physical measures in the river might be needed, such as creating favourable gravel for spawning, restoring rapids and pool sequences in the river, creating shelter in the river bed as hiding-places for fish, and removing fine sediment that inhibits spawning. Atle Harby, a senior research scientist, said that the new handbook – a world first of its type – can counter the current belief held by many that salmon inevitably suffer as a result of electric power generation in regulated rivers. Harby heads the CEDREN research centre – one of Norway’s “national teams” in environmentally-friendly energy, and which is manned by scientists from SINTEF Energy Research, the Norwegian University of Science and Technology (NTNU) and the Norwegian Institute for Nature Research (NINA).

No contradiction

He said: “Increased hydropower generation and larger salmon stocks are not necessarily a contradiction in terms. We can use new knowledge and new methods to increase salmon production without compromising power production in many of the regulated rivers. And this can be done using measures that don’t necessarily require major investments. “It won’t be possible everywhere, and in some rivers we have still to choose between salmon and power. But it is quite possible in many important salmon rivers to produce more salmon while maintaining existing power generation. We believe that our conclusions will be valid for a good number of important highly-regulated rivers. “We hope that the handbook will be used to identify what will be possible in each individual river.” Torbjørn Forseth, a senior scientist at NINA, said that salmon is an important indicator species in rivers. If salmon are doing well, and reproduce and thrive as they should, then other aspects of the river’s ecological system are also probably functioning well. Many of the handbook’s recommendations do not cost money. Much can be achieved by concentrating releases of water down the river during periods that are important for the salmon’s living conditions. Water temperature, riverbed structures and habitat conditions are important for the salmon and vary from year to year, but can be monitored and improved by river management. Forseth added that while transfer of water from neighbouring rivers can be costly, it is another possible option to ensure that hydropower companies and salmon have more water to share. – Climate News Network.

FOR IMMEDIATE RELEASE Scientists produce handbook that shows how better river management can mean more breeding success for migratory fish and more electricity from a vital source of renewable energy LONDON, 13 October – Hydropower can dramatically alter rivers and destroy the habitat of migratory species such as salmon, but now scientists have shown that it is perfectly possible for rivers to produce more fish and more electricity at the same time. After years of experience with hydro schemes in their own country, Norwegian scientists have produced a handbook to assist river engineers and to explain how to protect vulnerable species while exploiting rivers for renewable energy. The Centre for Environmental Design of Renewable Energy (CEDREN) believes that by understanding the needs of migratory fish and controlling the flow of the river to accommodate their lifestyle, the breeding success can be improved. At the same time, by adapting and improving the turbine capacity and making it more flexible, more energy can be produced. While the handbook is based on experience in Norway, the same principles can be applied to many rivers in mountainous areas that have salmon or other migratory fish. Some of the ideas might also apply to fast-flowing rivers in places such as the Himalayas, the European Alps, the Rockies in North America, and the Andes in South America. There is resistance in many of these places to hydropower because it can cause drastic alteration to natural rivers and destroy their wildlife. As a result, there is still a large untapped potential for hydropower schemes in some regions.

Cheap and reliable

The handbook is intended as a blueprint to help engineers and environmentalists to work together to improve the habitat for wildlife, while extracting much-needed electricity from water power to help combat climate change. Hydropower is one of the cheapest and most reliable of renewables. As far as salmon rivers are concerned, the handbook says the first task is to identify current problems that limit salmon production in rivers. These include lack of spawning grounds or shelter, low water periods, or periods of disadvantageous water temperature. Looking at the existing or potential hydropower, engineers need to work out operating strategies for the power stations to avoid interfering with the salmon. These could include ideas such as transferring water from neighbouring rivers to improve flow at critical times, and increasing the capacity of turbines and waterways to make operation more flexible. How the available water in the river is used is critical. Water flow to ensure environmental quality and water releases at different times of the year need to be closely regulated. To achieve this, a flexible “water bank” will be required to ensure a good supply of water when needed. There also needs to be a smooth transition between high and low water flows, with some water being saved for critical periods. Physical measures in the river might be needed, such as creating favourable gravel for spawning, restoring rapids and pool sequences in the river, creating shelter in the river bed as hiding-places for fish, and removing fine sediment that inhibits spawning. Atle Harby, a senior research scientist, said that the new handbook – a world first of its type – can counter the current belief held by many that salmon inevitably suffer as a result of electric power generation in regulated rivers. Harby heads the CEDREN research centre – one of Norway’s “national teams” in environmentally-friendly energy, and which is manned by scientists from SINTEF Energy Research, the Norwegian University of Science and Technology (NTNU) and the Norwegian Institute for Nature Research (NINA).

No contradiction

He said: “Increased hydropower generation and larger salmon stocks are not necessarily a contradiction in terms. We can use new knowledge and new methods to increase salmon production without compromising power production in many of the regulated rivers. And this can be done using measures that don’t necessarily require major investments. “It won’t be possible everywhere, and in some rivers we have still to choose between salmon and power. But it is quite possible in many important salmon rivers to produce more salmon while maintaining existing power generation. We believe that our conclusions will be valid for a good number of important highly-regulated rivers. “We hope that the handbook will be used to identify what will be possible in each individual river.” Torbjørn Forseth, a senior scientist at NINA, said that salmon is an important indicator species in rivers. If salmon are doing well, and reproduce and thrive as they should, then other aspects of the river’s ecological system are also probably functioning well. Many of the handbook’s recommendations do not cost money. Much can be achieved by concentrating releases of water down the river during periods that are important for the salmon’s living conditions. Water temperature, riverbed structures and habitat conditions are important for the salmon and vary from year to year, but can be monitored and improved by river management. Forseth added that while transfer of water from neighbouring rivers can be costly, it is another possible option to ensure that hydropower companies and salmon have more water to share. – Climate News Network.

Himalayas to be wetter and warmer over next century

FOR IMMEDIATE RELEASE There have been dire warnings about melting glaciers in the Himalayas leading to falling flows in some of Asia’s major’s rivers. Now scientists are turning some of their original research on its head. LONDON, 10 August – The river systems fed by the glaciers of the Himalayas and the Tibetan plateau are a vital source of water, food and energy for hundreds of millions of people downstream. Trying to predict the impact of climate change on glaciers in such a large and inaccessible area as the Himalayas – with research made more difficult by bitter intra regional rivalries – is no easy task.  While some studies say rising temperatures in the mountains and the melt of glaciers will lead to falling river levels downstream and drought in what is one of the most densely populated regions on the planet, other reports paint a more sanguine picture. In a study in the journal Nature Geoscience, scientists say that in two of the region’s most important river basins – the Ganges and the Indus – water levels are unlikely to drop over the next century.  This contrasts with earlier studies – including one by the same authors – suggesting water levels in these rivers would drop significantly by 2050, threatening the livelihoods of millions. The new report, Rising river flows throughout the twenty-first century in two Himalayan glacierized watersheds, says that in some parts of the Himalayan region, river flow losses as a result of less glacial meltwater will be compensated by an increase in monsoon rains. The lead author of the report is Dr Walter Immerzeel, a mountain hydrology and climate change specialist at Utrecht University  and at present a visiting scientist at the International Centre for Integrated Mountain Development (ICIMOD) in Nepal. Four years ago Immerzeel and his colleagues published a report predicting a considerable drop in water levels in the same rivers by 2050. “We are now using a more advanced glacier model that takes into consideration how slowly glaciers respond to climate change” says Dr Immerzeel. Marc Bierkens, professor of Hydrology at Utrecht and a report co author, says the modelling research shows the size of the glaciers in the watershed of the Indus and the Ganges will decrease during the 21st century. “Yet, surprisingly enough, water discharge in this region is increasing, rather than decreasing. The reasons vary greatly from one watershed to another. Bierkens told Climate News Network that the latest research findings were the result of using a more sophisticated ice model together with a new set of climate models and the fact that, especially in the western Himalayas, the increase in rainfall with height is larger than previously thought. To understand the impact of climate change on river discharge, researchers created computer models of glacier movements and water balance in both the Indus and the Ganges watersheds. The models indicated that in the eastern watershed – in Langtang in Nepal where the Ganges has its source – the relatively smaller glaciers melt quite quickly but an increase in monsoon rains leads to a growth in water discharge. In the western watershed – in Baltoro in Pakistan where the Indus has its source – the climate is dryer and colder and has much larger glaciers. The models show discharges in the area are increasing, mainly as a result of more glacial melting. Such melting, says the study, will peak around 2070 and thereafter drop but will  be compensated for by an increase in precipitation. “While the results of the research predict a somber future for the Himalayan glaciers, they offer some good news for water and food security in India, Bangladesh and Pakistan” says a report summary. – Climate News Network      

FOR IMMEDIATE RELEASE There have been dire warnings about melting glaciers in the Himalayas leading to falling flows in some of Asia’s major’s rivers. Now scientists are turning some of their original research on its head. LONDON, 10 August – The river systems fed by the glaciers of the Himalayas and the Tibetan plateau are a vital source of water, food and energy for hundreds of millions of people downstream. Trying to predict the impact of climate change on glaciers in such a large and inaccessible area as the Himalayas – with research made more difficult by bitter intra regional rivalries – is no easy task.  While some studies say rising temperatures in the mountains and the melt of glaciers will lead to falling river levels downstream and drought in what is one of the most densely populated regions on the planet, other reports paint a more sanguine picture. In a study in the journal Nature Geoscience, scientists say that in two of the region’s most important river basins – the Ganges and the Indus – water levels are unlikely to drop over the next century.  This contrasts with earlier studies – including one by the same authors – suggesting water levels in these rivers would drop significantly by 2050, threatening the livelihoods of millions. The new report, Rising river flows throughout the twenty-first century in two Himalayan glacierized watersheds, says that in some parts of the Himalayan region, river flow losses as a result of less glacial meltwater will be compensated by an increase in monsoon rains. The lead author of the report is Dr Walter Immerzeel, a mountain hydrology and climate change specialist at Utrecht University  and at present a visiting scientist at the International Centre for Integrated Mountain Development (ICIMOD) in Nepal. Four years ago Immerzeel and his colleagues published a report predicting a considerable drop in water levels in the same rivers by 2050. “We are now using a more advanced glacier model that takes into consideration how slowly glaciers respond to climate change” says Dr Immerzeel. Marc Bierkens, professor of Hydrology at Utrecht and a report co author, says the modelling research shows the size of the glaciers in the watershed of the Indus and the Ganges will decrease during the 21st century. “Yet, surprisingly enough, water discharge in this region is increasing, rather than decreasing. The reasons vary greatly from one watershed to another. Bierkens told Climate News Network that the latest research findings were the result of using a more sophisticated ice model together with a new set of climate models and the fact that, especially in the western Himalayas, the increase in rainfall with height is larger than previously thought. To understand the impact of climate change on river discharge, researchers created computer models of glacier movements and water balance in both the Indus and the Ganges watersheds. The models indicated that in the eastern watershed – in Langtang in Nepal where the Ganges has its source – the relatively smaller glaciers melt quite quickly but an increase in monsoon rains leads to a growth in water discharge. In the western watershed – in Baltoro in Pakistan where the Indus has its source – the climate is dryer and colder and has much larger glaciers. The models show discharges in the area are increasing, mainly as a result of more glacial melting. Such melting, says the study, will peak around 2070 and thereafter drop but will  be compensated for by an increase in precipitation. “While the results of the research predict a somber future for the Himalayan glaciers, they offer some good news for water and food security in India, Bangladesh and Pakistan” says a report summary. – Climate News Network