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Open accessJournal ArticleDOI: 10.1080/07900627.2019.1591941

Exploring management approaches for water and energy in the data-scarce Tekeze-Atbara Basin under hydrologic uncertainty

04 Mar 2021-International Journal of Water Resources Development (Routledge)-Vol. 37, Iss: 2, pp 182-207
Abstract: This study examines management approaches for hydropower generation and irrigation and domestic water supply for the Tekeze-Atbara, a transboundary river between Ethiopia, Eritrea and Sudan...

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Topics: Water-energy nexus (59%), Hydropower (58%), Water supply (54%)
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Open accessJournal ArticleDOI: 10.1016/J.JHYDROL.2019.124085
Abstract: This study performs a temporal analysis of nine water-energy nexus indicators for hydropower generation and irrigation water pumping. The Blue Nile, a major tributary of the Nile, within Sudan is taken as an example to demonstrate the temporal evolution of the nine nexus indicators. The indicators are water-energy productivity, firm daily energy generation, percentage of days at power generation capacity, variation in daily energy generation, annual energy generation, highest daily pumping energy, lowest daily pumping energy, variability in daily pumping energy, and annual pumping energy. A daily calibrated and validated water balance model of the Lower Blue Nile is used to construct time series for the nine indicators from 1984 to 2016. Time series analysis is performed to detect significant trends and regime shifts in the nine indicators. The analysis reveals that the heightening of the Roseires Dam in 2012/2013, one of the dams in the study region, resulted in significant shifts in annual energy generation, percentage of days at power generation capacity, variation in daily energy generation, water-energy productivity, and annual pumping energy. The significant shift (an increase in this case) that occurred in the percentage of days at power generation capacity indicates that the hydropower capacity of the Roseires Dam could be raised to utilize its hydropower potential more efficiently. It is shown that annual hydro-energy generation in the study region is dependent on water availability in the dry season (November to June). The temporal analysis of the nexus indicators demonstrates ability to detect significant natural phenomena and human interventions in the hydrological system. Understanding the temporal dynamics of the water-energy nexus is key to efficient utilization of water and energy resources, especially in a basin like the Nile where considerable alterations to the headwaters are underway.

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Topics: Water-energy nexus (56%), Hydropower (54%), Water pumping (52%) ... read more

13 Citations


Open accessJournal ArticleDOI: 10.1016/J.COMPCHEMENG.2020.106936
Abstract: This study introduces a novel energy, water and food nexus ‘Node’ methodology which includes: (a) decentralization using GIS-based approaches; (b) development of composite geospatial risk indicators using the Analytical Hierarchy Process; and (c) assessment of resource utilization. The methodology is applied to open fields agriculture, conventional greenhouses and hydroponic greenhouses in Qatar using the following nine risk factors: temperature, humidity, solar radiation, soil quality (As and Fe concentration), groundwater depth, groundwater recharge rate, groundwater salinity and groundwater pH. The analysis concludes that the critical factors that increase risk in open field farms are weather factors, such as temperature, solar radiation and humidity, with relative weights of 0.18527, 0.16860 and 0.15785, respectively, whilst groundwater factors have the highest impact on conventional and hydroponic greenhouses. Furthermore, although hydroponic greenhouses are more efficient in terms of water consumption in comparison to open fields, they consume more energy due to cooling and desalination requirements.

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Topics: Groundwater recharge (55%), Groundwater (51%)

12 Citations


Open accessJournal ArticleDOI: 10.1007/S00477-019-01706-X
Abstract: The integrative approach of water, energy, and food nexus (WEF nexus) is now widely accepted to offer better planning, development, and operation of these resources. This study presents a first attempt towards understanding the WEF nexus of urban environments in the Nile River Basin under conditions of hydrological droughts and fluvial floods. A case study was conducted for the capital of Sudan, Khartoum, at the confluence of the White Nile and the Blue Nile for illustration. The results were based on analyses of river flow and water turbidity data, field observations, a printed questionnaire and an interview of farmers practicing irrigated agriculture, and hydropower modeling. The study analyzes indicators for the association of the river water resources environment (intra-annual regime, quantity, and quality), the status of urban irrigated agriculture, water treatment for domestic use, and hydropower generation under hydrological extremes, i.e. droughts and fluvial floods. It additionally examines the consequent interactions between the impacts on three sectors. The present study shows how floods and droughts impose impacts on seasonal river water quality and quantity, water treatment for domestic use, irrigated agriculture, and hydro-energy supply in an urban environment. The results demonstrate how the two hydrological phenomena determine the state of hydropower generation from dams, i.e. high energy production during floods and vice versa during droughts. Hydropower dams, in turn, could induce cons in the form of low fertile soils in the downstream due to sediment retention by the reservoir. Finally, present and potential options to minimize the above risks are discussed. This study is hoped to offer good support for integrated decision making to increase the resource use efficiency over the urban environment within the Nile Basin.

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Topics: Water resources (59%), Hydropower (56%), Resource (biology) (52%) ... read more

11 Citations


Open accessJournal ArticleDOI: 10.3390/W12082237
08 Aug 2020-Water
Abstract: Due to renewed interest in hydropower dams in the face of climate change, it is important to assess dam operations and management in combination with downstream impacts on rivers in (semi-)arid environments. In this study, the impacts of the Tekeze hydropower dam on downstream hydrology and river morphology were investigated, including impacts under normal and extreme reservoir operation conditions. Field observations, in-depth interviews, repeat terrestrial photographs, multi-year high-resolution satellite images, daily reservoir water levels and data on hourly to daily energy production were collected and studied. The results show that high flows (Q5) have declined (with factor 5), low flows (Q95) have increased (with factor 27), seasonal flow patterns have smoothened, river beds have incised (up to 4 m) and locally aggraded near tributary confluences. The active river bed has narrowed by 31%, which was accelerated by the gradual emergence of Tamarix nilotica and fruit plantations. A new post-dam equilibrium had been reached until it was disrupted by the 2018 emergency release, caused by reservoir management and above-normal reservoir inflow, and causing extensive erosion and agricultural losses downstream. Increased floodplain occupation for irrigated agriculture consequently provides an additional argument for reservoir operation optimization to avoid future risks for riparian communities.

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Topics: River morphology (55%), Tributary (53%), Hydropower (53%) ... read more

7 Citations



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74 results found


Book ChapterDOI: 10.1007/978-0-387-75692-9_9
01 Jan 2008-
Topics: Jackknife resampling (67%)

6,130 Citations


Journal ArticleDOI: 10.1016/J.RSE.2011.02.019
Abstract: MODIS global evapotranspiration (ET) products by Mu et al. [Mu, Q., Heinsch, F. A., Zhao, M., Running, S. W. (2007). Development of a global evapotranspiration algorithm based on MODIS and global meteorology data. Remote Sensing of Environment, 111, 519–536. doi: 10.1016/j.rse.2007.04.015] are the first regular 1-km 2 land surface ET dataset for the 109.03 Million km 2 global vegetated land areas at an 8-day interval. In this study, we have further improved the ET algorithm in Mu et al. (2007a, hereafter called old algorithm) by 1) simplifying the calculation of vegetation cover fraction; 2) calculating ET as the sum of daytime and nighttime components; 3) adding soil heat flux calculation; 4) improving estimates of stomatal conductance, aerodynamic resistance and boundary layer resistance; 5) separating dry canopy surface from the wet; and 6) dividing soil surface into saturated wet surface and moist surface. We compared the improved algorithm with the old one both globally and locally at 46 eddy flux towers. The global annual total ET over the vegetated land surface is 62.8 × 10 3 km 3 , agrees very well with other reported estimates of 65.5 × 10 3 km 3 over the terrestrial land surface, which is much higher than 45.8 × 10 3 km 3 estimated with the old algorithm. For ET evaluation at eddy flux towers, the improved algorithm reduces mean absolute bias (MAE) of daily ET from 0.39 mm day −1 to 0.33 mm day −1 driven by tower meteorological data, and from 0.40 mm day −1 to 0.31 mm day −1 driven by GMAO data, a global meteorological reanalysis dataset. MAE values by the improved ET algorithm are 24.6% and 24.1% of the ET measured from towers, within the range (10–30%) of the reported uncertainties in ET measurements, implying an enhanced accuracy of the improved algorithm. Compared to the old algorithm, the improved algorithm increases the skill score with tower-driven ET estimates from 0.50 to 0.55, and from 0.46 to 0.53 with GMAO-driven ET. Based on these results, the improved ET algorithm has a better performance in generating global ET data products, providing critical information on global terrestrial water and energy cycles and environmental changes.

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1,672 Citations


Open access
30 Oct 2006-
Abstract: The Review's executive summary states that "the Review first examines the evidence on the economic impacts of climate change itself, and explores the economics of stabilizing greenhouse gases in the atmosphere. The second half of the Review considers the complex policy challenges involved in managing the transition to a low-carbon economy and in ensuring that societies can adapt to the consequences of climate change that can no longer be avoided". The report's main conclusion is that the benefits of strong, early action on climate change considerably outweigh the costs.

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1,464 Citations


Open accessJournal ArticleDOI: 10.1094/PDIS-11-11-0999-PDN
10 Apr 2012-Plant Disease
Abstract: From May to June 2011, during a survey of the wheat-growing areas in Meknes in the Sais Region of Morocco, several cyst nematode populations were detected. Sampling was performed 1 month before wheat (Triticum durum) harvest, in fields showing patches of stunted plants. Plants were growing poorly, had chlorotic lower leaves, and a reduced numbers of ears. Root systems were short and had a bushy appearance because of increased secondary root production. No cysts were visible on the roots, but were found in the soil. Cysts were collected from soil on 200-μm sieves by the modified Cobb decanting and sieving method (1) and identified by morphology and internal transcribed spacer (ITS)-rDNA sequencing. All isolates were identified as Heterodera avenae except the isolate from Ain Jemâa. From the latter, key morphological features from cysts and second-stage juveniles (J2) were determined. The cysts (n = 10) had the following characteristics: bifenestrate vulval cone, body length without neck 590 μm (551 to 632 μm), body width 393 μm (310 to 490 μm), neck length 75 μm (65 to 90 μm), fenestra length 64 μm (60 to 72 μm) and width 21 μm (18 to 25 μm), underbridge length 96 μm (85 to 115 μm), vulval slit length 8 μm (7 to 9 μm), vulva bridge width 27 μm (24 to 33 μm), and bullae absent. The J2s (n = 10) had the following characteristics: body length 445 μm (412 to 472 μm), body width 19 μm (19 to 21 μm), stylet length 24 μm (23 to 25 μm), four lateral lines, tail length 50 μm (46 to 54 μm), and hyaline terminal tail 28 μm (24 to 31 μm). Values of the morphological characters were within the range of H. latipons reported by Handoo (3). The bifenestrate cysts with a strong underbridge and no bullae and J2 with a tail length greater than 40 μm, a stylet longer than 15 μm, and four incisures in the lateral field were typical for H. latipons. To confirm the identification, molecular observations were made. DNA was extracted from three juveniles from three different cysts separately (4). The ITS-rDNA region was amplified using the primers 5'-CGT AAC AAG GTA GCT GTA G-3' and 5'-TCC TCC GCT AAA TGA TAT G-3' as described by Ferris et al. (2). This resulted in a 1,040-bp DNA fragment. The PCR-products were purified and sequenced (Macrogen, Inc., Seoul, Korea). All sequences obtained (GenBank Accession Nos. per cyst: JQ319035, JQ319036, and JQ319037) were compared with sequences available from the GenBank database ( www.ncbi.nlm.nih.gov ), including several species of Heterodera. This comparison revealed a sequence similarity of 97 to 99% with H. latipons and 89% or lower with any other species of Heterodera. Morphological and molecular identification demonstrated that the population of cyst nematodes from a wheat field in Ain Jemâa, Morocco was H. latipons. In the patches with poor growing plants, 65 cysts per 100 cm3 soil were found. To our knowledge, this detection represents a new record of H. latipons. Since the nematode can cause considerable damage to wheat, one of the main cereals produced in Morocco, care should be taken to prevent the spread to other regions. References: (1) K. R. Barker. Page 19 in: An Advanced Treatise on Meloidogyne. Vol II. Methodology. C. C. Carter and J. N. Sasser, eds. North Carolina State University Graphics, Raleigh, 1985. (2) V. R. Ferris et al. Fundam. Appl. Nematol. 16:177, 1993. (3) Z. A. Handoo. J. Nematol. 34:250, 2002. (4) M. Holterman et al. Mol. Biol. Evol. 23:1792, 2006.

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Topics: Heterodera latipons (60%), Cereal cyst nematode (54%), Heterodera avenae (51%) ... read more

1,083 Citations


Open accessJournal ArticleDOI: 10.1038/SDATA.2018.214
30 Oct 2018-Scientific Data
Abstract: We present new global maps of the Koppen-Geiger climate classification at an unprecedented 1-km resolution for the present-day (1980–2016) and for projected future conditions (2071–2100) under climate change. The present-day map is derived from an ensemble of four high-resolution, topographically-corrected climatic maps. The future map is derived from an ensemble of 32 climate model projections (scenario RCP8.5), by superimposing the projected climate change anomaly on the baseline high-resolution climatic maps. For both time periods we calculate confidence levels from the ensemble spread, providing valuable indications of the reliability of the classifications. The new maps exhibit a higher classification accuracy and substantially more detail than previous maps, particularly in regions with sharp spatial or elevation gradients. We anticipate the new maps will be useful for numerous applications, including species and vegetation distribution modeling. The new maps including the associated confidence maps are freely available via www.gloh2o.org/koppen . Machine-accessible metadata file describing the reported data (ISA-Tab format)

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Topics: Climate classification (58%), Climate model (55%)

975 Citations