scholarly journals OPTIMAL OPERATION OF MULTIPURPOSE RESERVOIRS IN SERIES: ROSEIRES AND SENNAR CASE STUDY

2021 ◽  
pp. 5-23
Author(s):  
T. Z. Saad Omer ◽  
S. E. Ahmed ◽  
A. Karimi
Keyword(s):  
Climate Change ◽  
Water Supply ◽  
Water Demand ◽  
Optimal Operation ◽  
Nile River ◽  
Blue Nile ◽  
Rule Curves ◽  
Water Demands ◽  
Operation Rules ◽  
Change Impact

The Roseires-Sennar Dams System (RSDS) at lower part of Blue Nile River play a vital role in water supply to the irrigation schemes in Sudan. The existing rule curves for this system belong to 1925 and 1966 for Sennar and Roseires reservoirs, respectively. Introduction of new irrigation schemes, approved climate change impacts on Blue Nile River flow and upstream developments in Ethiopia as well as the heightening of the Roseires Dam from elevation 480 to 490 m.a.s.l have shown the RSDS is losing its efficiency in terms of fully supplying the water demands. The literature addresses the simulation of Roseires and Sennar dams, and tries to find the best coordinated rule curves through a limited number of operation rules to find optimal operating rules for reservoirs that minimize the impacts of new developments, water demand growth and climate change on water supply to various demands on Blue Nile River. Such decisions are locally optimal in best condition since they do not consider the storage and carry-over capability of reservoirs that can transfer the non-optimal (locally optimal) decisions to other time steps of planning horizon and creat shortages in other time steps. Therefore, aim of this research is to find optimal coordinating operation rules for Roseires and Sennar dams that through a non-linear multi-period optimization model that considers the conditions of climate change, flow regime and water demand as scenarios. Model is validated by comparison with observed reservoir operation during November 1999 till May 2000. Eighteen scenarios that cover the normal, dry and very dry flow regimes, along with three suggested crop patterns and climate change impact are analyzed. Results shows in normal conditions of flow, crop pattern 2 is the most recommended with more than 11 Billion USD marginal profit and fully supplying the water demand and 1530 GWh energy generation per annum. The coordinated rule curves have a totally different pattern of emptying and filling compared with existing ones. Rule curves change from one flow regime to another, which proves how change in conditions of the system has influence on optimal operation rules. Comparison of marginal profits with crop pattern 2 shows in three inflow conditions of normal, dry and very dry years multi-period optimization model could keep the marginal profits above 11 Billion USD, let’s say, 11,050, 11,056 and 11,042 Billion USD, respectively, which shows the robustness of model in dealing with all conditions and keeping the marginal profits not affected. However, the Roseires rule curves are different in these three condition, while Sennar rules curves are almost the same. Without climate change impact, model can manage to supply the water demands fully in all flow conditions. However, water supply reliability is affected by climate change with all crop patterns. Roseires-Sennar Dams system in a normal year under climate change can produce 10,688 Billion USD marginal profit and 1371 GWh per year energy. It shows that model could manage the system performance so that climate change decrease the marginal profit by 3.27%, while inflow is reduced by 25% and water demands and evaporation increased by 19%. Energy generation under climate change has decreased by 10.5%, which is the most affected sector. Crop pattern 2 and 3 are not suitable for climate change conditions since up to 65% deficit in water supply can happen if very dry year realizing with climate change. In very dry conditions crop pattern 1 is more suitable to be practiced.

scholarly journals Water demand predictions for megacities: system dynamics modeling and implications

Water Policy ◽  
2017 ◽  
Vol 20 (1) ◽  
pp. 53-76 ◽  
Author(s):  
Huanhuan Qin ◽  
Ximing Cai ◽  
Chunmiao Zheng
Keyword(s):  
Climate Change ◽  
Water Supply ◽  
System Dynamics ◽  
Water Demand ◽  
Water Shortage ◽  
Dynamics Modeling ◽  
Water Transfers ◽  
Water Demands ◽  
Linear Relationships ◽  
Basin Water

Abstract Sustaining the water supply in megacities is an enormous challenge. To address this challenge, it is especially important to predict water demand changes in megacities. This paper presents a system dynamics model to predict the future water demands of different sectors considering multiple factors, including population, structure of the economy, and water supply and use technologies. Compared with traditional methods such as the time series method and structure analysis method, the proposed model takes into account the interconnections, non-linear relationships and feedbacks between the various factors in a systems context. The model is applied to Beijing, a megacity with a population over 20 million and very limited water availability. It is found that the total water demand is likely to increase by at least 36.1% (up to 62.5%) by 2030 compared with that in 2011, and the water deficits vary from −0.36 × 109 to 1.80 × 109m3 in 2030. In addition, scenarios are designed to account for impacts associated with economic development, climate change and inter-basin water transfers. It is shown that climate change may have a large impact on the water supply reliability in Beijing. The water shortage problems can be alleviated via inter-basin water transfers.

From individualistic behavior to full cooperation: optimal management policy design under varying cooperation levels in the Nile River basin

2020 ◽  
Author(s):  
Giacomo Trombetta ◽  
Andrea Castelletti ◽  
Matteo Giuliani ◽  
Marta Zaniolo ◽  
Paul Block
Keyword(s):  
Water Supply ◽  
River Basin ◽  
Optimal Operation ◽  
Management Policy ◽  
Nile River ◽  
Blue Nile ◽  
High Aswan Dam ◽  
Aswan Dam ◽  
Nile River Basin ◽  
Full Cooperation

<p>Transboundary river basins worldwide are commonly managed by unique, institutionally independent decision makers and characterized by multiple stakeholders with conflicting interests, including distribution, co-management, and use of water resources across sectors and among countries. This competition is expected to exacerbate in the future due to climate change induced water scarcity, increasing demand, and the development of infrastructure, which is often criticized for potentially jeopardizing downstream security by affecting water supply, irrigation, and energy production. </p><p>The Nile River basin is an emblematic transboundary basin, encompassing 11 countries and home to one-third of the African population. The largest fraction of Nile River streamflow originates in Ethiopia and is conveyed into the system via the Blue Nile. However, the larger water users have historically been downstream, in particular Egypt, where the High Aswan Dam (HAD) constitutes the backbone of Egyptian electricity supply and enables the irrigation of vast agricultural districts. This geographic disparity between water origination and consumption provides both the potential for conflict and the rationale for cooperation. Currently, the ongoing construction of the soon-to-be largest dam in Africa, the Grand Ethiopian Renaissance Dam (GERD) on the Blue Nile, is highly debated given concerns rising from how it will affect water supply and power generation in downstream countries. However, GERD may represent a response to the frequent regional power shortages, foster economic development, and represents a unique opportunity for cooperation between riparian countries from which all parties can benefit.</p><p>In this work we explore how varying levels of cooperation among the riparian countries, from individualistic behavior to full cooperation, might impact hydropower production and irrigated agriculture in the Nile River basin. We use an Evolutionary Multi-Objective Direct Policy Search approach to design optimal operation of a three-dimensional reservoir system, including GERD (Ethiopia), HAD (Egypt), and Merowe Dam (Sudan), under historical hydro-climatic conditions and under different cooperation levels, assuming the capacity of re-optimization of the High Aswan Dam and the Merowe Dam. Expected results may illustrate the benefits of implementing a centralized rather than an individualistic strategy, highlighting the value of full information exchange and of basin-wide cooperation.</p>

scholarly journals Assessing the Uncertainty of Hydropower-Environmental Conflict-Resolution Management under Climate Change

Water ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2114
Author(s):  
Yuni Xu ◽  
Yu Hui
Keyword(s):  
Climate Change ◽  
Conflict Resolution ◽  
Reservoir Operation ◽  
Yangtze River ◽  
Optimal Operation ◽  
Environmental Conflict ◽  
Climate Scenarios ◽  
Water Demands ◽  
Environmental Conflict Resolution ◽  
Decision Behaviors

To balance the water demands of different departments and produce a win–win result for reservoir operation, a series of conflict-resolution methods have been developed to define the socio-optimal operation strategy for specific conflict problems. However, given the inherent uncertainty of reservoir operation brought by climate change, the compromised strategies selected by conflict-resolution methods can vary. Therefore, quantifying the impacts of climate change on the decision characteristics of conflict-resolution methods can help to address questions about whether conflict-resolution decisions are sustainable given unforeseen changes. In this study, the Yangtze River is regarded as study area. As a world-class hydropower project located on the midstream of Yangtze River, Three Gorges Hydroelectric Power Station can transfer plenty of water energy into electricity. To alleviate the ecological water shortage caused by hydropower operation, sustainable and balanced operation strategies considering the water demands of two departments needs to be studied. In the context of hydropower-environmental conflict-resolution management, the decision behaviors of two fuzzy social choice methods and four game-theoretical bargaining methods under 25 kinds of future climate scenarios are analyzed. Comparing the strategy selection results of different methods for a future period (2021–2082) shows that in all proposed climate scenarios, the decisions of the Nash bargaining method, alternating offer method, and unanimity fallback bargaining method in game-theoretical bargaining methods are more stable than other studied methods, which means that climate change affects the decision behaviors of these three methods slightly. In addition, balanced strategies selected by these three methods could formulate adaptable reservoir operation policies that would satisfy the interests of hydropower and environmental stakeholders equally, and avoid a very low satisfaction level of individual stakeholder and whole stakeholders in the water-conflict year. Therefore, against the background of an increasing demand for environmental protection, these three methods can provide socio-optimal strategies considering social and economic benefits for water resource management.

scholarly journals Climate change impact on river flow extremes in the Upper Blue Nile River basin

2018 ◽  
Vol 10 (4) ◽  
pp. 759-781 ◽  
Author(s):  
Hadush K. Meresa ◽  
Mulusew T. Gatachew
Keyword(s):  
Climate Change ◽  
River Basin ◽  
Climate Change Impact ◽  
River Flow ◽  
Nile River ◽  
Hydrological Models ◽  
Hydrological Extremes ◽  
Dry Spell ◽  
Change Impact ◽  
Blue Nile River Basin

Abstract This paper aims to study climate change impact on the hydrological extremes and projected precipitation extremes in far future (2071–2100) period in the Upper Blue Nile River basin (UBNRB). The changes in precipitation extremes were derived from the most recent AFROCORDEX climate data base projection scenarios compared to the reference period (1971–2000). The climate change impacts on the hydrological extremes were evaluated using three conceptual hydrological models: GR4 J, HBV, and HMETS; and two objective functions: NSE and LogNSE. These hydrological models are calibrated and validated in the periods 1971–2000 and 2001–2010, respectively. The results indicate that the wet/dry spell will significantly decrease/increase due to climate change in some sites of the region, while in others, there is increase/decrease in wet/dry spell but not significantly, respectively. The extreme river flow will be less attenuated and more variable in terms of magnitude, and more irregular in terms of seasonal occurrence than at present. Low flows are projected to increase most prominently for lowland sites, due to the combined effects of projected decreases in Belg and Bega precipitation, and projected increases in evapotranspiration that will reduce residual soil moisture in Bega and Belg seasons.

scholarly journals Impact of Climate Change on Reservoir Reliability: A Case of Bhumibol Dam in Ping River Basin, Thailand

2021 ◽  
Vol 19 (4) ◽  
pp. 266-281
Author(s):  
Allan Sriratana Tabucanon ◽  
◽  
Areeya Rittima ◽  
Detchasit Raveephinit ◽  
Yutthana Phankamolsil ◽  
...  
Keyword(s):  
Climate Change ◽  
Water Demand ◽  
Rainfall Variability ◽  
Wet Season ◽  
Impact Of Climate Change ◽  
Operating Rules ◽  
Operation Rules ◽  
The Future ◽  
Reservoir Release ◽  
The Impact

Bhumibol Dam is the largest dam in the central region of Thailand and it serves as an important water resource. The dam’s operation relies on reservoir operating rules that were developed on the basis of the relationships among rainfall-inflow, water balance, and downstream water demand. However, due to climate change, changing rainfall variability is expected to render the reliability of the rule curves insecure. Therefore, this study investigated the impact of climate change on the reliability of the current reservoir operation rules of Bhumibol Dam. The future scenarios from 2000 to 2099 are based on EC-EARTH under RCP4.5 and RCP8.5 scenarios downscaled by RegCM4. MIKE11 HD was developed for the inflow simulation. The model generates the inflow well (R2=0.70). Generally, the trend of increasing inflow amounts is expected to continue in the dry seasons from 2000-2099, while large fluctuations of inflow are expected to be found in the wet seasons, reflecting high uncertainties. In the case of standard deviations, a larger deviation is predicted under the RCP8.5 scenario. For the reservoir’s operation in a climate change study, standard operating procedures were applied using historical release records to estimate daily reservoir release needed to serve downstream water demand in the future. It can be concluded that there is high risk of current reservoir operating rules towards the operation reliability under RCP4.5 (80% reliability), but the risk is lower under RCP8.5 (87% reliability) due to increased inflow amounts. The unmanageability occurs in the wet season, cautioning the need to redesign the rules.

scholarly journals Water-Centric Nexus Approach for the Agriculture and Forest Sectors in Response to Climate Change in the Korean Peninsula

Agronomy ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1657
Author(s):  
Chul-Hee Lim
Keyword(s):  
Climate Change ◽  
Water Balance ◽  
Water Supply ◽  
Water Demand ◽  
Korean Peninsula ◽  
Spatial Models ◽  
Climatic Conditions ◽  
Agricultural Water ◽  
Adaptation To Climate Change ◽  
The Future

Climate change has inherent multidisciplinary characteristics, and predicting the future of a single field of work has a limit. Therefore, this study proposes a water-centric nexus approach for the agriculture and forest sectors for improving the response to climate change in the Korean Peninsula. Two spatial models, i.e., Environmental Policy Integrated Climate and Integrated Valuation of Ecosystem Services and Tradeoffs, were used to assess the extent of changes in agricultural water demand, forest water supply, and their balance at the watershed level in the current and future climatic conditions. Climate changed has increased the agricultural water demand and forest water supply significantly in all future scenarios and periods. Comparing the results with RCP8.5 2070s and the baseline, the agricultural water demand and forest water supply increased by 35% and 28%, respectively. Water balance assessment at the main watershed level in the Korean Peninsula revealed that although most scenarios of the future water supply increases offset the demand growth, a risk to water balance exists in case of a low forest ratio or smaller watershed. For instance, the western plains, which are the granary regions of South and North Korea, indicate a higher risk than other areas. These results show that the land-use balance can be an essential factor in a water-centric adaptation to climate change. Ultimately, the water-centric nexus approach can make synergies by overcoming increasing water demands attributable to climate change.

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