scholarly journals Remotely sensed reservoir water storage dynamics (1984–2015) and the influence of climate variability and management at global scale

2021 ◽  
Author(s):  
Jiawei Hou ◽  
Albert van Dijk ◽  
Hylke Beck ◽  
Luigi Renzullo ◽  
Yoshihide Wada

Abstract. Many thousands of large dam reservoirs have been constructed worldwide during the last seventy years to increase reliable water supplies and support economic growth. Because reservoir storage measurements are generally not publicly available, so far there has been no global assessment of long-term dynamic changes in reservoir water volume. We overcame this by using optical (Landsat) and altimetry remote sensing to reconstruct monthly water storage for 6,743 reservoirs worldwide between 1984 and 2015. We relate reservoir storage to resilience and vulnerability and analyse their response to precipitation, streamflow and evaporation. We find reservoir storage has diminished substantially for 23 % of reservoirs over the three decades but increased for 21 %. The greatest declines were for dry basins in southeastern Australia (−29 %), the USA (−10 %), and eastern Brazil (−9 %). The greatest gains occurred in the Nile Basin (+67 %), Mediterranean basins (+31 %) and southern Africa (+22 %). Many of the observed reservoir changes were explained well by changes in precipitation and river inflows, emphasising the importance of multi-decadal precipitation changes for reservoir water storage, rather than changes in net evaporation or (demand-driven) dam water releases.

2003 ◽  
Vol 47 (1) ◽  
Author(s):  
Christian Zeller

Elements of a geography of capitalism. Despite the variety of new approaches economic geography developed rather one-sided in the past decade. The regional and the firm lenses hardly enabled to recognize how economic processes and political power relations interact on different scales. These empirical deficits also express a restricted theoretical base. The approaches of the new “regional orthodoxy” claim to explain conditions of an improved competitiveness of firms and of regions. However, many socially relevant and spatially differentiated problems are ignored. In contrast, this paper argues for an integrative understanding of the capitalist economy in its historical dynamics and with its reciprocal effects for actors on various scales. In the course of neoliberal deregulation policies and globalization processes, a finance-dominated accumulation regime emerged in the USA which shapes the economy on a global scale. Institutional investors gained decisive control over investments. The political power relations and hierarchies between states remain important. Therefore, the paper suggests a shift of economic geographical research. In the perspective of an integrative geography of capitalism the paper outlines a research agenda of a geography of accumulation, a geography of production as well as a geography of power


2013 ◽  
Vol 33 (2) ◽  
pp. 249-257 ◽  
Author(s):  
Alberto Colombo ◽  
Lívia A. Alvarenga ◽  
Myriane S. Scalco ◽  
Randal C. Ribeiro ◽  
Giselle F. Abreu

The increasing demand for water resources accentuates the need to reduce water waste through a more appropriate irrigation management. In the particular case of irrigated coffee planting, which in recent years presented growth with the predominance of drip irrigation, the improvement of drip irrigation management techniques is a necessity. The proper management of drip irrigation depends on the knowledge of the spatial pattern of soil moisture distribution inside the wetted strip formed under the irrigation lines. In this study, grids of 24 tensiometers were used to determine the water storage within the wetted strip formed under drippers, with a 3.78 L h-1 discharge, evenly spaced by 0.4 m, subjected to two different management criteria (fixed irrigation interval and 60 kPa tension). Estimates of storage based on a one-dimensional analysis, that only considers depth variations, were compared with two-dimensional estimates. The results indicate that for high-frequency irrigation the one-dimensional analysis is not appropriate. However, under less frequent irrigation, the two-dimensional analysis is dispensable, being the one-dimensional sufficient for calculating the water volume stored in the wetted strip.


Author(s):  
Sayyid Arrasyid ◽  
Zahidah Hasan ◽  
Izza Mahdiana Apriliani ◽  
Heti Herawati

Cirata Reservoir is one of the three cascade reservoirs fed by the Citarum Watershed with an area of ​​62 km2 (6.200 ha) and has a water volume of 1.900 million m3. The great potential of the waters in the Cirata Reservoir is utilized by the local community as a source of livelihood, namely by conducting aquaculture activities using floating net cages (FNC) in excess. FNC is thought to be a source of waste that reduces reservoir water quality. This research aims to determine the impact of FNC cultivation on primary productivity with different FNC densities at each station. The research was conducted in Cianjur Regency by taking on three stations, namely in the areas of Jangari, Maleber, and Patok Beusi on November 6 - December 8, 2019. The method used in the research was purposive sampling then analyzed in detail and quantitatively. The results show that reservoir waters have an average of physical parameters, namely temperature 32.2-32.6oC, transparency 0.59-0.68 meters, pH 7.1-7.3, carbon dioxide 15.4-16.1 mg / l, Dissolved Oxygen 6.9-7.3 mg / l, Biochemical Oxygen Demand 6.1-7.8 mg / l, nitrate 0.208-0.222 mg / l, ammonia 0.002833-0.003056 mg / l, phosphate 0,165-0,167 mg / l and primary productivity 240,36-277,90 mgC/m3/hour. This shows that the water indicator is still classified as good because it does not exceed the water quality standard.


2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Kongzhong Hu ◽  
Jiankang Chen ◽  
Dong Wang

Due to the demand in flood season for power generation, the first-stage face slab of a high concrete-face rockfill dam often must be constructed ahead of schedule, and advanced water storage is needed for the reservoir. Since the dam-body filling has not yet been completed at this point, the internal stress of the first-stage face slab is more complicated than that of normal construction. Taking Buxi Power Station as an example, the first-stage face slab temporary construction seam showed large areas of shear stress damage during the rise in reservoir water levels during the second segment of the second construction stage. The concrete-face slab showed large-piece brittle bulging, and the steel rebar was exposed and developed contortional deformation. Based on the monitoring data for Buxi Power Station along with the first-stage fracture characteristics of Shuibuya concrete face, this paper applied a numerical analysis to conduct research on the causes of fracture mechanics. The results indicate that the cracks occurred on the face slab during the second segment of second-stage water storage primarily due to the advanced concrete pouring of the first-stage face slab; during the first stage of reservoir water storage, the internal stress of the first-stage face slab was not reduced or eliminated prior to second-stage face slab pouring. Thus, with the rise in the reservoir water level, the shear stress increased continuously, eventually leading to partial large-scale shear stress failure of the first-stage face slab. The research results provide important references for the design and construction of concrete-face rockfill dams.


2021 ◽  
Author(s):  
Cristina Passet ◽  
Lan Wang-Erlandsson ◽  
Yoshihide Wada ◽  
Agnes Pranindita ◽  
Agatha De Boer

<div><span>A<strong> </strong>substantial portion of groundwater abstracted from aquifers is used for irrigation and evaporated to the atmosphere, potentially contributing towards downwind precipitation. While the fate of evaporation fluxes from land have been analysed, the atmospheric pathways of evaporation originating from groundwater have not yet been globally quantified. This study analysed the geographical distribution, the seasonality and the magnitude of groundwater-dependent precipitation (Pgw) </span><span>at a global scale and for a selection of countries and river basins. The Eulerian moisture tracking WAM-2layers model was used to process meteorological and groundwater abstraction input data from 1980 to 2010.  Results show considerable contributions of groundwater to precipitation downwind of the most heavily irrigated areas, leading to net groundwater losses over these areas. Globally, 40% of the Pgw </span><span>precipitates directly in the oceans, and do not contribute to biomass production in terrestrial ecosystems. Some of the countries with the highest rates of groundwater abstraction (India, the USA, Pakistan and Iran), receive low volumes of Pgw </span><span>and are net losers of groundwater resources. The countries with the highest net gain of groundwater are China, Canada and Russia. At river basin scale, the Indus, Ganges and Mississippi basins are net losers of groundwater to downwind Pgw</span><span>, while the Yangtze, Tarim and Brahmaputra basins receive more Pgw </span><span>than their groundwater withdrawals. The share of precipitation that originates from groundwater varies considerably with seasons, and can be especially high when low local precipitation levels occur in combination with high upwind groundwater abstraction. Furthermore, precipitation dependence on </span><span>groundwater (ρgw)</span><span>, has steadily increased between 1980 to 2010 in all studied areas and globally. Our study suggests that the countries and basins with a high and increasing dependency on ρgw </span><span>to support their precipitation can be vulnerable to groundwater availability upwind.</span></div>


1998 ◽  
Vol 35 (02) ◽  
pp. 119-125
Author(s):  
Bahadir lnozu ◽  
Peter G. Schaedel ◽  
Veronique Molinari ◽  
Philippe Roy ◽  
Robert Johns

An industry-wide international network is needed to collect Reliability, Availability and Maintainability (RAM) data on shipboard machinery and share this data at different levels by linking vessel chief engineers, ship operators-managers, regulatory agencies, equipment manufacturers, and shipyards/designers. This network should facilitate the efficient collection and flow of RAM information between these entities with industry-wide continuous improvement in safety and cost-effectiveness. This paper describes the implementation of a worldwide information network, called RAM/SHIPNET to support the optimization of safety, reliability and cost effectiveness throughout all stages of a vessel's life cycle. Development of this network was started with seed funding from SNAME and continued under the umbrella of the Ship Operations Cooperative Program with primary funding from the Gulf Coast Region Maritime Technology Center at the University of New Orleans. First generation data collection and processing tools have been completed and, pilot validation and testing has been performed in the USA. The project is now moving into the second implementation stage enabling full scale testing, validation and roll-out on a global scale. A call is made to the industry for suggestions on improvement to meet emerging needs.


Sensors ◽  
2020 ◽  
Vol 20 (9) ◽  
pp. 2626 ◽  
Author(s):  
Damian Absalon ◽  
Magdalena Matysik ◽  
Andrzej Woźnica ◽  
Bartosz Łozowski ◽  
Wanda Jarosz ◽  
...  

Maintaining good condition of dam reservoirs in urban areas seems increasingly important due to their valuable role in mitigating the effects of global warming. The aim of this study is to analyze possibilities to improve water quality and ecosystem condition of the Paprocany dam reservoir (highly urbanized area of southern Poland) using current data of the water parameters, historical sources, and DPSIR (Driver–Pressure–State–Impact–Response) and 3D modeling concerning human activity and the global warming effects. In its history Paprocany reservoir overcame numerous hydrotechnical changes influencing its present functioning. Also, its current state is significantly influenced by saline water from the coal mine (5 g L−1 of chlorides and sulphates) and biogenic elements in recreational area (about 70 mg L−1 of chlorate and to 1.9 mg L−1 Kjeldahl nitrogen) and in sediments (222.66 Mg of Kjeldahl nitrogen, 45.65 Mg of P, and 1.03 Mg of assimilable phosphorus). Concluding, the best solutions to improve the Paprocany reservoir water quality comprise: increasing alimentation with water and shortening the water exchange time, restoration of the 19th century water treatment plant, and wetlands and reed bed area revitalization. The study also proved the applicability of mathematical models in planning of the actions and anticipating their efficiency.


2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Okba Selama ◽  
Phillip James ◽  
Farida Nateche ◽  
Elizabeth M. H. Wellington ◽  
Hocine Hacène

Databases are an essential tool and resource within the field of bioinformatics. The primary aim of this study was to generate an overview of global bacterial biodiversity and biogeography using available data from the two largest public online databases, NCBI Nucleotide and GBIF. The secondary aim was to highlight the contribution each geographic area has to each database. The basis for data analysis of this study was the metadata provided by both databases, mainly, the taxonomy and the geographical area origin of isolation of the microorganism (record). These were directly obtained from GBIF through the online interface, whileE-utilitiesandPythonwere used in combination with a programmatic web service access to obtain data from the NCBI Nucleotide Database. Results indicate that the American continent, and more specifically the USA, is the top contributor, while Africa and Antarctica are less well represented. This highlights the imbalance of exploration within these areas rather than any reduction in biodiversity. This study describes a novel approach to generating global scale patterns of bacterial biodiversity and biogeography and indicates that theProteobacteriaare the most abundant and widely distributed phylum within both databases.


2018 ◽  
Vol 16 (2) ◽  
pp. 321-328
Author(s):  
Faissal Aziz ◽  
Naaila Ouazzani ◽  
Laila Mandi ◽  
Aziz Assaad ◽  
Steve Pontvianne ◽  
...  

Abstract Water storage tanks, fed directly from the river through opened channels, are particular systems used for water supply in rural areas in Morocco. The stored water is used as drinking water by the surrounding population without any treatment. UV-visible spectroscopy and fluorescence spectroscopy (excitation-emission matrices and synchronous fluorescence) have been tested as rapid methods to assess the quality of the water stored in the reservoirs as well as along the river feeding them. Synchronous fluorescence spectra (SFS50), collected with a difference of 50 nm between excitation and emission wavelengths, revealed a high tryptophan-like fluorescence, indicative of a pollution induced by untreated domestic and/or farm wastewater. The best correlations were obtained between the total SFS50 fluorescence and dissolved organic carbon (DOC) and biological oxygen demand, showing that the contribution of humic-like fluorescent substances cannot be neglected to rapidly assess reservoir water quality in terms of DOC by fluorescence spectroscopy.


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