Hydropower Developments Research Articles

Ecological compensation for inundated habitats in hydropower developments based on carbon stock balance

Hydroelectric power reservoirs have been identified as potentially important sources of greenhouse gas (GHG) emissions due to the large areas of habitat which are inundated, leading to doubts as to whether hydropower is actually a net low-carbon energy source. In this study we propose a ‘service-to-service’ ecological analysis of inundated habitats from the viewpoint of carbon stock balance compared with the carbon stock loss from hydropower reservoirs. We consider whether the lost ecological service of carbon sequestration by inundated farmland, grassland and woodland could be offset by an increased ecological service provided by a grassland rehabilitation project. We also establish an integrated ecological compensation accounting methodology for inundated habitats by combining habitat equivalency analysis and estimates of carbon stock loss. This ecological compensation framework is illustrated by calculations from a case study of the Pondo hydropower project in Tibet, China. The results estimate that the total carbon stock losses from the construction and operation of this reservoir was 124,662 tons; requiring a compensatory restoration of areas of slightly, moderately, or severely degraded grasslands of 17.80, 8.90, and 5.93 thousand hectares, in a lump-sum payment mode. By means of such ecological compensations, carbon stock balance could be realized at the watershed scale, and the advantages of low-carbon hydropower developments could be fully realized.

Upstream and downstream responses of fish assemblages to an eastern Amazonian hydroelectric dam

Summary Major hydroelectric dams are proliferating in tropical regions such as Amazonia, where extensive new hydropower developments are planned despite potentially severe ecological and social impacts. The status of freshwater biota in the vicinity of existing dams could be valuable to predict the effects of such developments, but detailed ecological monitoring before and after dam construction is frequently lacking. In the absence of these data, we used a space‐for‐time replacement to compare a key component of the aquatic biota at upstream and downstream sites, with the latter more closely resembling river channel conditions prior to the dam. We assessed the fish assemblages upstream and downstream of the Coaracy Nunes Dam in Amapá, Brazil, the first ecological study at this site since this dam was constructed 42 years earlier. We used gillnets during eight bimonthly field campaigns, covering both wet and dry seasons, and sampled the ichthyofauna (1819 individuals, 81 species) at four sites: Downstream Channel, Reservoir, Upstream Lake and Upstream Channel. We found clear negative impacts on the abundance, biomass, species richness, alpha diversity and species dominance upstream of the dam. The physical subdivision of the river channel and the upstream channel conversion from lentic to lotic habitats were strongly associated with differences in the composition and structure of fish communities. Notable changes include an increased contribution of small‐bodied fish in the reservoir and an absence of long‐distance migrants upstream of the dam. Downstream channel habitats, in particular, retained their fish diversity with high conservation value typical of eastern Amazonia, yet these areas now face the threat of new hydropower development farther downstream. The long‐term impacts on aquatic biodiversity highlighted in this study are especially relevant in the face of burgeoning new hydroelectricity development plans for rivers across lowland Amazonia.

Hydroclimatic changes and drivers in the Sava River Catchment and comparison with Swedish catchments.

In this study, we investigate long-term hydroclimatic changes and their possible relation to regional changes in climate, land-use and water-use over the twentieth century in the transboundary Sava River Catchment (SRC) in South Eastern Europe. In a hydropower dominated part of the SRC, unlike in an unregulated part, we find increase in average annual evapotranspiration and decrease in temporal runoff variability, which are not readily explainable by observed concurrent climate change in temperature and precipitation and may be more related to landscape-internal change drivers. Among the latter investigated here, results indicate hydropower developments as most closely related to the found hydroclimatic shifts, consistent with previous such indications in studies of Swedish hydropower catchments. Overall, the present results have quantitatively framed the recent history and present state of hydroclimate in the SRC, of relevance for water resources in several countries and for a majority of their populations. This provides a useful basis for further assessment of possible future hydroclimatic changes, under different scenarios of climate change and land/water-use developments in the region.Electronic supplementary materialThe online version of this article (doi:10.1007/s13280-015-0641-0) contains supplementary material, which is available to authorized users.

Using Choice Experiments to Assess Environmental Impacts of Dams in Portugal

Despite their well-known benefits in electricity production, dams are also responsible for some adverse environmental impacts affecting particularly the wellbeing of residents of the local communities. These environmental damages have not been included in the cost-benefit analysis of hydropower developments mainly because of the difficulty to determine their value. The prime objective of this paper is to measure the economic values of several environmental impacts due to the dams' activity in Portugal, using a discrete choice experiments approach. With the results of this research paper, we expect to contribute to a more efficient and thorough cost-benefit analysis within the complex process of deciding the optimal location of future dams to be built not only in Portugal, but elsewhere. The addition of this stage to the decision-making process allows the integration of economic, social and environmental dimensions, promoting a richer and more informed decision process.

Inter-annual variations in vegetation and their response to climatic factors in the upper catchments of the Yellow River from 2000 to 2010

To understand the variations in vegetation and their correlation with climate factors in the upper catchments of the Yellow River, China, Normalized Difference Vegetation Index (NDVI) time series data from 2000 to 2010 were collected based on the MOD13Q1 product. The coefficient of variation, Theil-Sen median trend analysis and the Mann-Kendall test were combined to investigate the volatility characteristic and trend characteristic of the vegetation. Climate data sets were then used to analyze the correlation between variations in vegetation and climate change. In terms of the temporal variations, the vegetation in this study area improved slightly from 2000 to 2010, although the volatility characteristic was larger in 2000–2005 than in 2006–2010. In terms of the spatial variation, vegetation which is relatively stable and has a significantly increasing trend accounts for the largest part of the study area. Its spatial distribution is highly correlated with altitude, which ranges from about 2000 to 3000 m in this area. Highly fluctuating vegetation and vegetation which showed a significantly decreasing trend were mostly distributed around the reservoirs and in the reaches of the river with hydropower developments. Vegetation with a relatively stable and significantly decreasing trend and vegetation with a highly fluctuating and significantly increasing trend are widely dispersed. With respect to the response of vegetation to climate change, about 20–30% of the vegetation has a significant correlation with climatic factors and the correlations in most areas are positive: regions with precipitation as the key influencing factor account for more than 10% of the area; regions with temperature as the key influencing factor account for less than 10% of the area; and regions with precipitation and temperature as the key influencing factors together account for about 5% of the total area. More than 70% of the vegetation has an insignificant correlation with climatic factors.

Influence of Hydropower Development on Flow Regime in the Zambezi River Basin for Different Scenarios of Environmental Flows

As the need for energy is increasing, the challenges in the future are to operate existing large hydraulic schemes in more sustainable ways and to develop future water resources projects that are able to achieve a better balance between environmental and socio-economic demands. In this context, scenarios combining different levels of environmental requirements as well as hydropower developments were simulated at a daily time step with a hydraulic-hydrological model (the Soil and Water Assessment Tool) over the Zambezi River Basin. For each scenario, the hydropower operation rules, the mean annual energy produced and the firm powers were considered. The impact on the flow regime was characterized by a hydrological alteration indicator and Pardé coefficients. In the present state, the total mean annual energy production is about 30,000 GWh with a firm power of about 3,000 MW. The impact of the dams on the flow regime is low in the Kafue flats and the Zambezi delta and high in the Mana Pools. The new run-of-river hydropower plants aim to increase the mean energy production by more than 90 % and the firm power by about 40 %. Releasing e-flows can reduce the impact in the Kafue flats and in the Zambezi delta, with a loss of less than 10 % of mean annual energy production and about 15 % of the firm power at Itezhi-Tezhi and Cahora Bassa. This reveals that a compromise between energy production and environmental sustainability can be reached.

Erratum to: Understanding the impact of hydropower developments in the context of upstream–downstream relations in the Mekong river basin

Erratum to: Understanding the impact of hydropower developments in the context of upstream–downstream relations in the Mekong river basin

Are hydropower and irrigation development complements or substitutes? The example of the Nam Ngum River in the Mekong Basin

Hydropower and irrigation developments to address rising demand for food and energy are modifying the water balance of the Mekong Basin. Infrastructure investment decisions are also frequently made from a sub-catchment perspective. This paper compares river flows with irrigation development stages in the Nam Ngum sub-basin where the potential for irrigation and hydropower expansion is largely untapped. It shows that full hydropower development in this basin allows irrigation water use to triple, even as it reduces competition with environmental flow requirements. The implications for the wider Mekong are, however, unclear, particularly given uncertainty over parallel transformations elsewhere in the basin.

The Isotope Hydrology of a Large River System Regulated for Hydropower

AbstractImpoundments, regulation and inter‐basin transfers associated with large hydropower developments affect runoff regimes, water residence times and stream water quality. We used stable isotopes to understand these effects on the river Tay system in Scotland, examining their spatial and temporal variation in surface waters at 22 sites. Spatial patterns of isotopes in stream water were consistent with those of precipitation, being more depleted in streams draining higher, colder northern headwaters and enriched in the milder western headwaters. To a lesser extent, spatial patterns also reflected effects of inter‐basin and intra‐basin water transfers at some sites. Temporal dynamics reflected precipitation inputs modulated by landscape properties, the presence of lakes and reservoirs, and regulation operations. Isotopic variability was highest in headwater tributaries with responsive soils and lowest downstream of lakes and reservoirs. Variability of isotopes in lower river sites was also damped as they integrate contributions from the rest of the catchment. Importantly, regulation from both reservoirs and inter‐basin transfers can distort simple input–output relationships for stable isotopes and affect catchment transit times with implications for water quality and in‐stream ecology. On the one hand, reservoirs and extension of natural lakes have created additional storage, potentially slowing flows; on the other, transfers have increased the volume and rates of water throughput in many of these water bodies, reducing hydraulic turnover times. Such effects tend to be quite localized and are not apparent at the larger catchment scale. Copyright © 2014 John Wiley & Sons, Ltd.

Water-quality management in a vulnerable large river: the Nile in Egypt

We review the severe water-management problems of the Nile Basin, where physical water scarcity is associated with high demographic growth, leading to a sharply rising demand for competing water uses such as hydropower and large-scale irrigation. Rapid economic growth is perceived as the means to emerge from the poverty trap that afflicts livelihoods in the Upper Basin and vital wetland ecosystem services such as fish biomass, freshwater biodiversity, groundwater recharge, flow regulation and local climate moderation are threatened by the water-development schemes and pollution that follow from this policy. Their cumulative impacts remain unaddressed. The High Aswan Dam's impacts on freshwater biodiversity are incompletely understood; a significant number of species may have become threatened as a result of its construction. Today the reservoir water quality is high, it is thought to support 47 fish species, its local human activities are restricted by central government regulations and recent estimates indicate that eutrophication threats are unlikely. Sediment and nutrient inputs coming into it from upstream will, however, continue to decrease in the near future as a result of newly built and planned dams in the upper basin. The dams will also reduce discharge and cause further loss of connectivity between the river and its floodplain, exacerbated by the possible completion of the Jonglei Canal bypassing the Sudd swamps. These impacts will affect the Nile's vulnerable aquatic biodiversity and regulatory services that are likely to affect local climate conditions. Under the current geopolitical scenario, management decisions that could favour participatory and sustainable options are over-ruled by high-level political trade-offs between the numerous riparian states. The financing of major hydropower developments by vested interests creates a scenario that is unlikely to favour sustainable resource management and conflict resolution.

ASSESSING THE CUMULATIVE IMPACTS OF HYDROPOWER REGULATION ON THE FLOW CHARACTERISTICS OF A LARGE ATLANTIC SALMON RIVER SYSTEM

ABSTRACTWe assessed the influence of hydropower on the flow characteristics of the river Tay, one of the UK's most heavily regulated catchments and important Atlantic salmon fisheries. Hydropower developments in the mid‐20th century preceded flow data collection, resulting in knowledge gaps over how far regulated flows deviate from natural and how ecosystem functioning might have been impacted. We used 29 unregulated catchments in and around the Tay to assess the relationships between hydroclimatic conditions, landscape structure and the overall flow regime, as well as the annual, monthly and daily flow metrics. This allowed the identification of flow characteristics by using an integrated suite of regression approaches (nonlinear, MLR and random forests) to assess likely impacts at 11 regulated sites. The results showed that the impacts of regulation are highly variable in both space and time. Headwater sub‐catchments are most heavily affected, and water imports or exports as part of hydropower schemes can increase or decrease annual runoff by up to 50%, respectively. On a monthly basis, regulation primarily increased summer low flows; winter high flows increased in catchments affected by water imports and reduced where there was a net water export. At larger catchment scales, impacts were relatively small, as unregulated tributaries re‐naturalize the flows and the effects of intra‐basin transfers balance. Non‐stationarity in climate and water use in the catchment dictates that adaptive management of flows may be necessary to protect ecosystems services. Copyright © 2013 John Wiley & Sons, Ltd.

Understanding the impact of hydropower developments in the context of upstream–downstream relations in the Mekong river basin

Hydropower developments along the main stem of the Mekong River and its tributaries cause transboundary effects within the Mekong Basin Region, which comprises parts of six countries. On the one hand, the provision of hydropower triggers economic development and helps to meet the rising energy demand of the Mekong riparian countries, especially China, Thailand, and Vietnam. On the other hand, the negative impact of dam construction, mainly altered water flow and sediment load, has severe impacts on the environment and the livelihoods of the rural Mekong population. Several discrepancies exist in the needs, demands, and challenges of upstream versus downstream countries. Against the common apprehension that downstream countries are powerlessly exposed to mainly negative impacts whereas upstream countries unilaterally benefit from hydropower, the authors argue that upstream–downstream relations are not really clear-cut. This conclusion is based on a consideration of the complex power play between Mekong riparians, with a focus on recent power trade interactions. The article investigates the consequences of hydropower dams for the Mekong region as well as the role of supranational players, such as the Mekong River Commission and the Greater Mekong Subregion Initiative, on the hydropower debate. It is not nations that are the winners or losers in the hydropower schemes in the Mekong, but rather parts of the riparian population: a few influential and powerful elites versus the large mass of rural poor.

Mekong at the Crossroads: Next Steps for Impact Assessment of Large Dams

Mekong at the Crossroads: Next Steps for Impact Assessment of Large Dams

Liming restores Atlantic salmon (Salmo salar) populations in acidified Norwegian rivers

Acidification has exterminated or seriously reduced Atlantic salmon ( Salmo salar ) populations in 40–45 Norwegian rivers. As this problem still exists, liming to restore salmon has been necessary, which now involves 21 of these rivers. Thirteen rivers were electrofished 1 year before liming and again 1–12 years later. There was a significant effect both of time after liming and status (e.g., formerly lost and reduced stocks) on the densities of both fry (age 0+) and parr (age ≥ 1+). However, the rate of increase in densities of young salmon in these two status categories was not significantly different in either age group. The development in parr densities suggests that more than 20 years of liming is required to restore salmon in rivers with lost native populations. Stocked rivers and rivers unaltered by hydropower developments generally had higher fry densities and faster increase in parr densities. Annual rod catches of adult salmon increased significantly after liming started, reaching about 45 t after 10 years of treatment. This is 11%–12% of the current total catch of Atlantic salmon in all Norwegian rivers. Liming thus makes an important contribution to the restoration of salmon in formerly acidified rivers.

Ecological attributes of a tropical river basin vulnerable to the impacts of clustered hydropower developments

The Vu Gia – Thu Bon River Basin in central Vietnam is subject to extensive hydropower development, with eight major and at least 34 minor hydropower installations planned for completion over the next 10 years. This intense clustering of hydropower developments has the potential to impact on aquatic fauna and ecosystems extensively. We sampled freshwater and estuarine fish across the river basin to evaluate the current status of the fish fauna, to determine the extent of zonal and habitat specialisation, to determine the prevalence of migration as a component of life-history strategies, to evaluate the likely magnitude of impacts, and to highlight areas where management intervention is needed and where more extensive study is most urgently required. Given the current high levels of exploitation, the fish fauna appeared surprisingly intact; however, a number of attributes of the fauna, such as the prevalence of migration as a life-history tactic, make this fauna particularly vulnerable to the impacts of hydropower development. Without extensive mitigation, the combinations of habitat alteration in dam and diversion areas and the imposition of a proliferation of barriers to migration will lead to severe population fragmentation, increasing the potential for local extinction, and severely compromise opportunities for recolonisation.

Integration of InSAR and GPS for hydraulic engineering

Interferometric synthetic aperture radar (InSAR) is a potential earth observation approach, and it has been demonstrated to have a variety of applications in measuring ground movement, urban subsidence and landslides. Currently InSAR provides the ability to map accurate DEM and measure ground deformation to sub-centimeter accuracy. However, many factors affect InSAR to measure ground movement since dam constructions are built in a large scale area with a complicated climate and unstable geology. This paper discusses potential applications of integrated InSAR and GPS to monitor a large-scale ground movement due to hydropower developments. The integration of InSAR and GPS can provide a cost-effective means for monitoring deformation of hydropower developments. Moreover, two novel methods, both the improved spatial interpolating method and estimation of 3D surface motion velocities method, are proposed and the experimental results and analysis are given in this paper.

Focus on the World: Status and Future of Hydropower

This paper describes the potential hydropower (HP) and water resources and developments to replace fossil and other conventional world's energy sources in the near future. Hydroelectric power has an important role to play in the future and provides considerable benefits to an integrated electric system. HP provides more than 97% of all electricity generated by renewable sources. The social, economic, and environmental impacts of large hydropower, however, highlight the serious limitations of large hydropower in sustainable energy development. HP is a clean energy source. It prevents the burning of 22 billion gallons of oil or 120 million tons of coal each year. HP does not produce greenhouse gasses or other air pollution. HP leaves behind no waste.

Hydrology and the natural heritage of the Scottish mountains

The physical natures of the Scottish mountains and their geographical position have created a montane environment, which can be considered as unique in European terms. The mountains of Scotland have been subjected to major environmental changes throughout the past centuries including climate change, deforestation, hydropower developments and more recently the expansion of plantation forestry. Mountain ecosystems have the ability to withstand large climatic variations and extreme events but it is suggested that they may not withstand some of the climatic barriers, which have recently been crossed. The greatest recent land use change in Scotland's mountains has been the expansion of plantation forests. The effects on headwater catchment hydrology are mainly in the reduction in runoff. It is suggested that plantation forestry has a more significant impact on the natural heritage through other influences such as water chemistry and river sediments. Future management of the Scottish mountains needs to consider the great natural heritage value in addition to other interests such as water resources, hydropower generation, commercial forestry and tourism.

Status of tunnelling and underground construction activities and technologies in India

A considerable amount of tunnelling work has been going on in India for hydroelectric, irrigation, roads and railways projects. Most of these projects are located away from urban areas. The use of tunnelling for urban utilities, such as water supply, sewerage disposal and metro rail has recently begun. A few projects have been completed and some are under construction in metropolises such as Mumbai, Calcutta and Delhi. The present status of tunnelling and its future potential in India is highlighted in the paper with emphasis on tunnelling projects for hydro-power developments, as this sector presently has maximum underground construction activity in India. The tunnelling technologies for planning, design and construction have also been presented in this paper.

Sustainable Environmental Outcomes from Water-related Energy Projects

This paper examines how two of the Kyoto Protocol mechanisms— the clean development mechanism (CDM) and emissions trading— have been applied to two water-related renewable power-generation projects. Traditional concerns related to hydropower developments are examined and discussed in the light of assessments carried out for a SMEC International promoted hydropower project in Nepal, which intends to sell power to India. SMEC International is promoting the idea of viewing the hydropower development under the CDM to the Nepalese and Indian governments, so that potential emission credits generated can be of mutual benefit to all three parties. SMEC International has been assisting the Government of Gujarat, India, in assessing various environmental issues related to the bold and imaginative proposal KALPASAR, which intends to dam a gulf and harness the high tidal variations to generate nearly 5000 MW of renewable power. The Government of Gujarat is proposing to seek national/international private sector involvement, thereby providing opportunities for developed country commercial entities to invest in a large-scale renewable energy project which can be considered under CDM, enabling emission credits generated to be of mutual benefit to relevant parties.