Km2 Reservoir Research Articles

Coupling effect of impoundment and irrigation on landslide movement in Maoergai Reservoir area revealed by multi-platform InSAR observations

The mountainous areas of Southwest China are crucial regions for hydropower resource development. The unique geological environment and numerous constructed hydropower stations make landslides the primary geological hazard for the region. Therefore, the deformation monitoring and mechanism analysis of reservoir landslides have attracted extensive attention from the academic community. The Maoergai Reservoir (MEGR) is located in the middle reaches of the Heishui River in Sichuan Province, China. Following impoundment, numerous active slopes have arisen in the reservoir area, with the Xierguazi-Mawo landslide complex (XMLC) potentially being the most threatening. In this paper, we first acquired the surface displacement of the MEGR area, before and after impoundment, using time series Synthetic Aperture Radar Interferometry (InSAR) analysis of the ALOS-1/PALSAR-1, ALOS-2/PALSAR-2 and Sentinel-1 datasets. Then, the three-dimensional (3D) deformation field was inverted by combining multi-track InSAR observations and a topography-constrained model. Results show the presence of 47 active landslides within the 675 km2 reservoir area, a significant increase compared to the seven landslides identified prior to impoundment. Based on the derived 3D velocity vectors, we found that the motion of the XMLC exhibits heterogeneity in terms of spatial and temporal patterns. Further, the displacement time series of all detected active landslides suggests that irrigation and water level fluctuations are two major factors influencing the kinematic behaviors of landslides. Irrigation accelerates landslide movement and thus permanently alters the deformation trend, while water level fluctuations cause seasonal oscillations in the displacement time series with a time lag of approximately 100 days. The above results can contribute to landslide management and prevention in the MEGR area and provide a representation for numerous water reservoirs in southwest China.

Monitoring a critical population of the Bolivian river dolphin, Inia boliviensis, before and after closing the floodgates of a hydroelectric dam in the Amazon Basin, Brazil: A quantitative analysis

Dam constructions threaten aquatic fauna, degrading their habitats and causing population fragmentation. Environmental impact studies were carried out from March 2010 to July 2015 as part of the licensing process concerning the Jirau Hydroelectric Dam construction, located on the Madeira River, Rondônia, Brazil, aiming to assess its impacts on the local fauna. The dam closed its gates in December 2012 and the water level rose from 2013 to 2015, creating a 468 km2 reservoir. Dams may be a source of negative effects to several species, including the Bolivian river dolphin, Inia boliviensis, which have a restricted distribution in northern Bolivian rivers and part of the Madeira River Basin. This study evaluated the presence of I. boliviensis in different sections of the Madeira River before reservoir filling (BRF) and after reservoir filling (ARF) through a quantitative analysis. Dolphins were actively searched along linear transects in four sections of the river: Abunã, Mutum, Caiçara and Canteiro, over 125 km (250 km round trip). A total effort of 986 h was carried out along 210 days during the hydrological seasons (falling, low, rising and high-water level). Twenty-nine (29) groups were recorded BRF in the direct dam influence area (N = 62), while thirty-eight (38) groups were documented ARF (N = 111). The highest number of sightings was recorded in Abunã during both periods: 24 in BRF (N = 50) and 33 in ARF (N = 101). The greatest number of dolphins was detected during the falling and low hydrological seasons: 19 in BRF (N = 48) and 30 in ARF (N = 92). This is expected, since decreasing water levels lead to a higher concentration of prey and, consequently, higher numbers of dolphins can be observed. Standardized methodology and experienced staff are essential to ensure adequate dolphin population estimates, especially in these critical habitats, where the main impacts caused by the dam are population fragmentation, isolation and extirpation, and reproductive segregation.

The potential of GRACE gravimetry to detect the heavy rainfall‐induced impoundment of a small reservoir in the upper Yellow River

AbstractArtificial reservoirs are important indicators of anthropogenic impacts on environments, and their cumulative influences on the local water storage will change the gravity signal. However, because of their small signal size, such gravity changes are seldom studied using satellite gravimetry from the Gravity Recovery and Climate Experiment (GRACE). Here we investigate the ability of GRACE to detect water storage changes in the Longyangxia Reservoir (LR), which is situated in the upper main stem of the Yellow River. Three different GRACE solutions from the CSR, GFZ, and JPL with three different processing filters are compared here. We find that heavy precipitation in the summer of 2005 caused the LR water storage to increase by 37.9 m in height, which is equivalent to 13.0 Gt in mass, and that the CSR solutions with a DDK4 filter show the best performance in revealing the synthetic gravity signals. We also obtain 109 pairs of reservoir inundation area measurements from satellite imagery and water level changes from laser altimetry and in situ observations to derive the area‐height ratios for the LR. The root mean square of GRACE series in the LR is reduced by 39% after removing synthetic signals caused by mass changes in the LR or by 62% if the GRACE series is further smoothed. We conclude that GRACE data show promising potential in detecting water storage changes in this ∼400 km2 reservoir and that a small signal size is not a restricting factor for detection using GRACE data.

Comparison of Satellite Reflectance Algorithms for Estimating Phycocyanin Values and Cyanobacterial Total Biovolume in a Temperate Reservoir Using Coincident Hyperspectral Aircraft Imagery and Dense Coincident Surface Observations

We analyzed 27 established and new simple and therefore perhaps portable satellite phycocyanin pigment reflectance algorithms for estimating cyanobacterial values in a temperate 8.9 km2 reservoir in southwest Ohio using coincident hyperspectral aircraft imagery and dense coincident water surface observations collected from 44 sites within 1 h of image acquisition. The algorithms were adapted to real Compact Airborne Spectrographic Imager (CASI), synthetic WorldView-2, Sentinel-2, Landsat-8, MODIS and Sentinel-3/MERIS/OLCI imagery resulting in 184 variants and corresponding image products. Image products were compared to the cyanobacterial coincident surface observation measurements to identify groups of promising algorithms for operational algal bloom monitoring. Several of the algorithms were found useful for estimating phycocyanin values with each sensor type except MODIS in this small lake. In situ phycocyanin measurements correlated strongly (r2 = 0.757) with cyanobacterial sum of total biovolume (CSTB) allowing us to estimate both phycocyanin values and CSTB for all of the satellites considered except MODIS in this situation.

Decadal changes in bathymetry of the Yangtze River Estuary: Human impacts and potential saltwater intrusion

This study analyzed bathymetric changes of the 77-km Yangtze River Estuary in China over the past ten years in order to understand the impacts of recent human activities on the estuary of a large alluvial river. Morphological changes were assessed by analyzing digitized bathymetric data of the estuarine channels from 2002 to 2013. Additionally, multi-beam bathymetric measurements made in 2012, 2014 and 2015 were utilized to investigate microtophographic bedforms of the lower reach of the estuary. Our results showed that the middle and upper reaches of the Yangtze River Estuary experienced substantial channel bed erosion in the past 10 years, and that the recent human activities have contributed to the change. These included the construction of a 70 km2 reservoir along the Yangtze River Estuary, the Qingcaosha Reservoir, for drinking water supply for the City of Shanghai, which has caused progressive bed erosion in the North Channel. The net volume of channel erosion in the Hengsha Passage from 2002 to 2013 was 0.86 × 108 m3. A large amount of the eroded sediment was trapped downstream, causing overall accretion in the upper reach of the North Passage. The middle and upper reaches of the South Passage also experienced intense erosion (0.45 × 108 m3) in the past ten years, while high accretion occurred in the lower reach because of the Deepening Waterway Project. The channel dredging left a large range of dredging marks and hollows in the North Passage. The increasing saltwater intrusion found in the Yangtze River Estuary may have been a consequence of either dredging or erosion, or both combined.

Mangla reservoir, Pakistan – approaching 50 years of service

The first issue, dated May 1967, of the newsletter of the British National Committee on Large Dams, now the British Dam Society, contained a brief item about Mangla reservoir, Pakistan: ‘The first stage impounding of water in the reservoir formed by Mangla, Sukian and Jari Dams was expected to take place in March, 1967.’ Mangla Dam project was the largest embankment dam project in the world at that time. The 260 km2 reservoir was formed by three major dams. The original designs included provision for raising the dams by up to 12 m to offset sedimentation. In 2000, the Government of Pakistan decided to exploit the raising provisions and thereby store flood water that would otherwise be routinely released. Advances in geotechnical and seismic engineering, changes in design parameters and information from 40 years performance of the dams were taken into account in revisiting the designs for the raising. Construction for a 9 m raise in conservation level began in 2004 and was completed in December 2009 requiring about 31 × 106 m3 of fill materials. The total length of dam embankment is 14 km, maximum height 148 m. It is one of the largest dam raising projects ever undertaken.

Estimates of reservoir methane emissions based on a spatially balanced probabilistic‐survey

AbstractGlobal estimates of methane (CH4) emissions from reservoirs are poorly constrained, partly due to the challenges of accounting for intra‐reservoir spatial variability. Reservoir‐scale emission rates are often estimated by extrapolating from measurement made at a few locations; however, error and bias associated with this approach can be large and difficult to quantify. Here, we use a generalized random tessellation survey (GRTS) design to generate unbiased estimates of reservoir‐CH4 emissions rates (±95% CI) for areas below tributary inflows, open‐waters, and at the whole‐reservoir scale. Total CH4 emission rates (i.e., sum of ebullition and diffusive emissions) were 4.8 (±2.1), 33.0 (±10.7), and 8.3 (±2.2) mg CH4 m−2 h−1 in open‐waters, tributary‐associated areas, and the whole‐reservoir for the period in August 2014 during which 115 sites were sampled across an 7.98 km2 reservoir in Southwestern, Ohio, U.S.A. Tributary areas occupy 12% of the reservoir surface, but were the source of 41% of total CH4 emissions, highlighting the importance of riverine‐lacustrine transition zones. Ebullition accounted for > 90% of CH4 emission at all spatial scales. Overall, CH4 emission rates were high for a temperate zone reservoir, possibly because earlier studies underestimated ebullition or did not include emission hot spots. Confidence interval estimates that incorporated spatial pattern in CH4 emissions were up to 29% narrower than when spatial independence is assumed among sites. The use of GRTS, or other probabilistic survey designs, can improve the accuracy and precision of reservoir emission rate estimates, which is needed to better constrain uncertainty in global scale emission estimates.

Sistemas de producción y potencial energético de la energía mareomotriz (Production systems and energy potential of tidal energy)

El presente artículo aborda el concepto de energía mareomotriz, haciendo una distinción de los tipos de sistemas de aprovechamiento de la energía de las mareas, de la misma manera se muestra el papel que esta tecnología desempeña como fuente de abastecimiento energético en algunos países alrededor del mundo, rol que está asociado al potencial energético disponible de cada región, aspecto que de igual forma se expone en el documento soportado en cifras de GWh/año por superficie embalsada en Km2. Por último, pero no menos importante, está la influencia que ha tenido esta tecnología en el medio ambiente, sus contribuciones y aspectos por mejorar y evaluar desde el punto de vista medioambiental.

Some geotechnical aspects of raising the Mangla dam, Pakistan

The Mangla dam project in Pakistan was the largest embankment dam project in the world when it was completed in 1967. The 260 km2 reservoir is formed by four major dams, each with a different cross-section, and each a significant structure. The original designs included provision for raising the dams by up to 12 m to offset the effects of future sedimentation. In 2000, capacity lost due to sedimentation became a significant issue. The government of Pakistan decided to exploit the raising provisions of the original design, and store flood water that was routinely being released. Following studies to confirm the most economic extent of raising, the original designs were reviewed and modified. Since the 1960s there have been advances in geotechnical and seismic engineering, changes in design parameters and information from 40 years' performance of the dams, all of which had to be taken into account in revisiting the designs for the raising. As a result, the dam cross-sections for the raised embankments have been adjusted using updated parameters, and the opportunity has been taken to address some areas of seepage that have been under observation since the original construction. Construction for a 9 m raise began in 2004 and was completed in December 2009. The total length of dam embankment after raising is 14 km, with a maximum height of 148 m. The work required 31 million m3 of fill materials, and is one of the largest dam-raising projects ever undertaken.

Significant ecosystem-wide effects of the swiftly spreading invasive freshwater bivalve Limnoperna fortunei

Since its introduction in South America around 1990, the freshwater Asian mussel Limnoperna fortunei has been shown to strongly interact with several components of the local biota. However, investigation of its ecosystem-wide effects was hindered by (1) difficulties associated with evaluation of its densities over large spatial scales and (2) scarcity of pre-invasion environmental data. The present survey overcomes these shortcomings and addresses the question whether Limnoperna’s impact on the ecosystem-wide scale is measurable and significant. On the basis of diver-collected bottom samples, we estimated the overall density of this mussel in a reservoir (Embalse de Rio Tercero, Argentina), where Limnoperna is present since 1998 and analyzed changes in several water-column properties before and after the invasion. The 47 km2 reservoir hosts around 45 billion mussels; at these densities, a volume equivalent to that of this water body can potentially be filtered by the bivalves every 2–3 days. Data collected regularly since 1996 indicate that after the invasion water transparency increased, and suspended matter, chlorophyll a, and primary production decreased significantly, with strong changes occurring in the area with highest mussel densities. Our results indicate that the ecosystem-wide impacts of Limnoperna are generally comparable to those described in Europe and North America for another invasive mussel—Dreissena polymorpha. However, given Limnoperna’s wider tolerance limits, its influence on newly invaded water bodies, potentially including Europe and North America, will probably be stronger.

Reservoir-Triggered Seismicity at the Toulnustouc Hydroelectric Project, Quebec North Shore, Canada

Hydro-Quebec’s Toulnustouc hydroelectric complex is located approximately 120 km north of Baie–Comeau on the Quebec North Shore region. The project involved the construction of a 77-m-high dam and a 45-m-high dike that allowed the expansion of an existing 235 km2 reservoir by some 22 km2. When completely filled, the new part of the reservoir has a maximum depth of 75 m. Starting on 10 February 2005 and over a period of four days, the water of the original reservoir was used to start filling the new part. The water level of the entire reservoir increased by another 10 m after the spring snowmelt. The project also included a 9.8-km-long headrace tunnel constructed in Precambrian bedrock that creates a 170-m water head between the reservoir and the powerhouse. Electricity production started in May 2005. The complex is located in an area of low-level earthquake activity on the Canadian Shield. Four stations of the Canada National Seismograph Network (CNSN) located within 100 km of the reservoir provide a location threshold with a magnitude of about 1.2 ( m N ). To complement the CNSN, two portable seismographs were installed near the flooded area and the headrace tunnel about one week before flooding started. Between February and mid-May 2005, a total of four triggered earthquakes were recorded by the field instruments and the CNSN stations. The first event, a magnitude 1.4 ( m N ), occurred 16 days after flooding of the extension of the reservoir started. Three events were located beneath the reservoir and one was near the tunnel between the reservoir and the powerhouse where the water pressure is most intense. Numerous smaller but unlocatable events ( m N <1.0) were detected by one of the field stations. About two years later, two events separated by one minute and recognized as multiplets occurred near the reservoir. The small stress perturbations that led to the reservoir-triggered seismicity at Toulnustouc support the hypothesis that the mid to upper crust of intraplate areas is in a state of stress close to failure.

Three Gorges Dam Project: An Introduction

The Three Gorges Dam Project (TGDP) on the Yangtze River in Hubei Province is touted as the long term solution to China’s increasing energy and agricultural needs. TGDP, with a 1084 km2 reservoir of 39.3 billion m3 capacity, will be the largest multipurpose water conservancy project ever built in the world. The main structures of the project are dam, hydropower stations and navigation facilities. After studying fifteen alternative sites and approval of Environmental Impact Statement (EIS) in February 1992, the construction of the dam began in 1994 with an expected duration of 17 years. &#x0D; Annual reduction of 40-50 million tons of coal consumption by providing 85 billion kilowatt hours of electricity, protection of 1.6 million hectares of agricultural land from floods and considerable improvement of navigation and tourism sector are the major anticipated benefits of TGDP. However, the proposed benefits put significant pressure on ecological and socio-cultural environment of the TGDP area. Relocation and resettlement of over 1.3 million local populations, inundation of several sites of historical importance, deforestation and loss of biodiversity including several endangered species of flora and fauna across a region of 58,000 km2, increased sedimentation, water pollution and potential earthquake risks are the major adverse consequences of TGDP.&#x0D; &#x0D; Key words: Three Gorges Dam Project (TGDP), environmental impacts, alternatives, resettlement, biodiversity, ecology, China&#x0D; &#x0D; Hydro Nepal: Journal of Water, Energy and Environment Vol. I, Issue No. 1 (2007) pp. 54-56

AN ASSESSMENT OF RETAINING DAMS IN HYDROPOWER RESERVOIRS FOR ENHANCING BIRD HABITAT

The River Inna in the south Norwegian subalpine region was regulated in 1979–1982, creating a 6.7 km2 reservoir with a 35 m range in water level. This reservoir inundated good habitat for wetland birds and, in general, provided poor habitat for birds. Along the main inflow river, but within the reservoir, a retaining dam was constructed after the breeding season in 1989 to create habitat for native ducks. The dam maintains a nearly constant water level about 1 m below the highest water level in the reservoir; this is especially important for ducks throughout the breeding season. The ducks showed an immediate response in the first season, increasing both in number of species and number of individuals of several species. To discern some factors responsible for attracting ducks to this pond, all ducks were censused at least 12 times each breeding season between 1990 and 1994. The numbers varied widely, both from one year to another and during each breeding season. Wigeon (Anas penelope) numbers after dam construction were highest early in the season. Tufted duck (Aythya fuligula) numbers mainly varied from one year to another, while long-tailed duck (Clangula hyemalis) numbers varied greatly through the season. In general, variations in water level had little effect on duck numbers. Four species established breeding populations in the pond. Such ponds may be valuable for establishing duck populations in many areas otherwise unsuitable for breeding water-birds. Appropriate management may also improve the chances of this being a rich habitat for several duck species in the future.

The Grazing Impact ofDaphnia parvulaon Phytoplankton in a Southeastern, Eutrophic Reservoir

ABSTRACT Zooplanktonic grazing is increasingly recognized as an important component of phytoplankton dynamics and composition in natural, north-temperate lakes. The most efficient grazers are species of the cladoceran genus Daphnia, but in southeastern reservoirs this genus is often sparse in abundance, particularly during summer. Further, the dominant daphnia is Daphnia parvula which is a small-bodied species possibly not capable of exerting similar controls on food resources as larger Daphnia species. Experimental exclosure of fishes from zooplankton in Jordan Lake, a eutrophic, 55 km2 reservoir in Piedmont North Carolina, was undertaken to determine if zooplankton would respond sufficiently to influence phytoplankton. Every major crustacean zooplankton taxon doubled its biomass within 2 weeks after protection from predators in at least 1 of six experiments from May to September. The usual numerical dominant, Skistodiaptomus pallidus, increased in every test by at least two-fold. D. parvula increased in...

The EI Cajon Reservoir: Developing Management Strategies for a Tropical Impoundment

ABSTRACT In 1984, a 94 km2 reservoir started to form behind the highest arch dam on the American continent, EI Cajon in Honduras. Pre-impoundment programs established to assess the environmental aspects of this hydroelectric project have developed into a post-impoundment research unit that is undertaking management-oriented studies on the reservoir and its watershed. Information from this research provides an excellent case history of the evolution of a tropical reservoir and associated management challenges. Accumulation of hydrogen sulfide in the anoxic hypolimnion has resulted in some corrosion problems in the power generation facility. The fisheries, which appear to have a substantial potential for contributing to employment and food supply in the region, are currently underexploited. However, as the regional social infrastructure develops, utilization of the fisheries production is expected to increase. As population pressure in the EI Cajon basin increases, the economic and environmental consequence...

Mathematical modelling of Yacyreta-Apipe scheme on the Rio Parana

The project concerns a section of approximately 200 km of the Rio Parana in Argentina. A 1 420 km2 reservoir will collect the waters of a 975.000 km2 catchment area and will store 16,900 million m3. Two spillways are designed for a flood flow of 95.000 m3/s. A compensating dam will store 2 180 Mm3 with a surface area of 800 km2. The operating discharge of the hydropower plant will be between 14.000 and 21.000 m3/s. The paper describes the project and the CARIMA flow model (design, construction, calibration, use).

L'aménagement hydroélectrique du territoire de la baie James

The James Bay Hydro Company has been mandated by the Government of Quebec to develop the waterways in the territory of James Bay to meet electricity requirements in the 1980's. The territory has a total area of 176 000 km2 , i.e. Close to one-third of the area of France. Whereas earlier projects, the Churchill and the Maniconagan - Outardes heads, (had been developed quite near the main communication routes, those in James Bay were developed in a quasi-Siberian environment where it was necessary to construct the transport and accommodation infrastructure. After ten years of work, over 85 % of the initial phase of the La Grande Riviere hydro-electric plant has now been completed. However, the development of the territory's rivers is far from complete. Twenty years will be needed to complete the second phase of the complex and implement two other projects : the Grande Riviere de la Baleine plant and the Nottaway, Broadback and Rupert river complex. The initial phase of the La Grande Complex - as it is known - includes the construction of three power stations, La Grande 2, La Grande 3 and La Grande 4 on the La Grande river. This river drains a 98 000 km2 basin with an average now of 1700013/sec. The underground station of La Grande 2, whose sixteen turbo-generator sets produce a total installed power of 5328 MW, has been in operation since 1981. The dam (length at the crest : 2835 m, height 160 m), has necessitated a 23 million m3 of earth fill, i.e. the same volume as was required for the thirty dykes retaining the water of the 2835 km2 reservoir. The spillway can discharge 15 300 m3/sec. The La Grande 3 station is equipped with twelve Francis turbines driving the same number of generators, which will produce 12.3 billion kWh. The first set was commissioned in June of last year. The La Grande 3 dam, the longest of the complex was completed in October 1980. The construction required a total volume of rockfill of 22.2 million m3. The 2460 km2 reservoir is confined by 67 dykes. The spillway is designed to discharge 10 100 m3/sec. The La Grande 4 station, like La Grande 3, is overground. With an installed power of 2637 MW, it will operate at full load in 1985, yielding an annual output of 14.1 billion kWh. Construction of the dam was completed in 1981 : 3600 m long, 125 m high, 20 million m3 of earthfill. There are eight dykes which correspond to an additional volume of 14 million m3 of fill. Two by-passes have been excavated to increase the potential of the La Grande river through two make-up reservoirs : the Eastmain by-pass and the Caniapiscau by-pass. The second phase of the La Grande plant includes the construction of five power stations, La Grande 1, Brisay, Laforge 1, Laforge 2 and Eastmain 1, which will add over 3200 MW to Quebec Hydro's installed power. The La Grande-Baleine plant will be installed on the Grande riviere de la Baleine, which is approximately at the same latitude as Moscow. Under the scheme construction is planned of three power stations (Grande-Baleine 1, Grande-Baleine 2 and Grande-Baleine 3), three spillways, one regulating structure and three new reservoirs. The total installed power of this plant will be 2900 MW. Under the programme presented by Quebec Hydro to the Government the first turbines would enter into service by 1990. The catchment basins of the three rivers, the Nottaway, the Broadback and the Rupert, where another complex (the NBR) will be developed, are located approximately 300 km south of La Grande Riviere. By combining the flows of these three rivers via relatively short canals and installing the bulk of the equipment on the lower section of the Broadback, it will be possible to obtain an annual output of approximately 47 billion kWh, i.e. approximately two-thirds of the output of the initial phase of the La Grande plant. Eleven power stations will be built, with a total installed power of 7 255 MW.