scholarly journals Assessment of optimal empty flushing strategies in a multi-reservoir system

2016 ◽  
Author(s):  
Frederick N.-F. Chou ◽  
Chia-Wen Wu
Keyword(s):  
Water Supply ◽  
Network Flow ◽  
Operation Mode ◽  
Water Shortage ◽  
Maximum Amount ◽  
Optimal Parameters ◽  
Joint Operation ◽  
Reservoir System ◽  
Network Flow Programming ◽  
Nonlinear Optimization Algorithm

Abstract. Empty flushing is the most effective approach to evacuate the deposited sediments in the reservoir. However, emptying reservoir essentially conflicts with its water supply operation, thus a feasible strategy of empty flushing should prevent significant increase of water shortage risks. This paper presents a framework of performing empty flushing in a multi-reservoir system, where flushing is carried out in a primary reservoir and the other reservoirs provide backup storage for stable water supply during flushing. A network flow programming-based model is employed to simulate daily joint operation of reservoirs. During the simulation, if the storage of each reservoir achieves the predefined conditions, drawdown and empty flushing of the primary reservoir is activated. During the flushing, if the storage of any reservoir reaches the pre-defined thresholds, then the flushing operation is halted and the simulation switches back to the regular joint operation mode. This simulation model is linked with a nonlinear optimization algorithm to calibrate the optimal parameters. The optimized strategy yields a maximum amount of flushed sediments, while the incremental water shortage is controlled within the acceptable threshold.

scholarly journals Minimizing the impact of vacating instream storage of a multi-reservoir system: a tradeoff study of water supply and empty flushing

2020 ◽  
Author(s):  
Chia-Wen Wu ◽  
Frederick N.-F. Chou ◽  
Fong-Zuo Lee
Keyword(s):  
Water Supply ◽  
Water Shortage ◽  
The Other ◽  
Flood Peak ◽  
Reservoir System ◽  
System A ◽  
Expected Benefits ◽  
The Impact ◽  
Nonlinear Optimization Algorithm

Abstract. Reservoir operator does not favor storage above a certain level in situations such as the pre-release operation prior to a flood, scheduled engineering constructions or mechanical excavations of sediments in the impoundments, drawdown and empty flushing, etc. This paper selects the last of which as the case study, and a method is presented to promote the feasibility of emptying reservoir storage. The impact of emptying reservoir on water supply is minimized through appropriate joint operation in a multi-reservoir system, where drawdown and empty flushing is carried out in a primary reservoir and the other reservoirs provide backup water for supply. This method prioritizes allocating the storage in the primary reservoir for water supply during specific periods prior to its empty. If the storage of every reservoir achieves its predefined conditions, drawdown of the primary reservoir is activated and followed by empty flushing. Previously preserved storage in the other reservoirs ensures adequate water supply during the periods of emptying the primary reservoir. Flushing of the primary reservoir is continued until either the accumulative released water exceeds the specified volume, storage in the backup reservoirs drops below the pre-defined threshold, or the inflow to the primary reservoir recedes from the flood peak to be below the releasing capacity of outlets. This behavior is simulated and linked with a nonlinear optimization algorithm to calibrate the optimal parameters defining the activation and termination of empty flushing. The optimized strategy limits the incremental water shortage within the acceptable threshold and maximizes the expected benefits of emptying reservoir.

scholarly journals Network Flow Analysis under Water Shortage and Decompressed Water Supply Control

2003 ◽  
Vol 123 (8) ◽  
pp. 1449-1455
Author(s):  
Hiromitsu Kurisu ◽  
Takashi Fukumoto ◽  
Hideyuki Tadokoro ◽  
Norihisa Komoda
Keyword(s):  
Water Supply ◽  
Network Flow ◽  
Flow Analysis ◽  
Water Shortage

scholarly journals Mitigate water shortage by improving hydropower generation strategy of the cascade reservoir system in the Be River Basin, Vietnam

2020 ◽  
Vol 20 (8) ◽  
pp. 3216-3232
Author(s):  
Nguyen Thi Thuy Linh ◽  
Frederick N.-F. Chou
Keyword(s):  
Water Resources ◽  
Water Supply ◽  
River Basin ◽  
Water Resources Management ◽  
Water Allocation ◽  
Water Shortage ◽  
Hydropower Generation ◽  
Water Shortages ◽  
Resources Management ◽  
Reservoir System

Abstract To meet increasing water consumption with limited water resources, management approaches that transfer water between purposes must be improved for sustainable development. This entails an urgent requirement for appropriate water resources management within water–energy interaction if severe water shortage occurs occasionally. This study evaluates hydropower generation policies of a cascade reservoir system in the Be River Basin in terms of security of water supply and energy production. The Generalized Water Allocation Simulation Model (GWASIM) was applied to simulate the water use of a complex system of hydropower generation and water supply. Two water allocation scenarios and six alternatives defined by varying monthly generating hours were modeled and compared. The results demonstrate that a compromise between hydropower generation and water supply can be negotiated to reduce the severity of water shortages. Different monthly hours of hydropower generation among alternatives show an effect on improving power production and reliable water supply. This study provides overall insight into the performance of a multi-purpose cascade reservoir system. It will provide a foundation for improving future study of reservoir operations in meeting the increasing demands of water and energy in Vietnam.

scholarly journals Optimizing the Management Strategies of a Multi-Purpose Multi-Reservoir System in Vietnam

Water ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 938
Author(s):  
Frederick N.-F. Chou ◽  
Nguyen Thi Thuy Linh ◽  
Chia-Wen Wu
Keyword(s):  
Water Supply ◽  
River Basin ◽  
Management Strategies ◽  
Water Shortage ◽  
Hydropower Generation ◽  
Water Shortages ◽  
Global Trends ◽  
Reservoir System ◽  
System A

Resource shortages are having an increasingly severe impact as global trends like rapid population growth, urbanization, economic development, and climate change unfold. Moreover, rising living standards across many regions are also affecting water and energy resources. This entails an urgent requirement to improve water resources management. An important improvement is to transfer water between the different uses of the reservoir system. A compromise between the needs of hydropower generation and the water supply can be negotiated for the reservoir system to reduce the severity of water shortages. The Be River basin in Vietnam was selected as a case study to investigate. The combination of the generalized water allocation simulation model (GWASIM) and the bounded optimization by quadratic approximation (BOBYQA) algorithm was applied to optimize hydropower generation in various water shortage scenarios. The results present optimized hydropower generation policies for cascade reservoirs that would significantly improve the present operating policy in terms of both the water supply and hydropower generation. Moreover, multiple scenarios will provide flexibility to the reservoir operator by giving the relationship between water and energy. Given water supply conditions, the operator will be able to choose among several optimal solutions to ensure greater water resource efficiency in the Be River basin.

scholarly journals Minimizing the impact of vacating instream storage of a multi-reservoir system: a trade-off study of water supply and empty flushing

2021 ◽  
Vol 25 (4) ◽  
pp. 2063-2087
Author(s):  
Chia-Wen Wu ◽  
Frederick N.-F. Chou ◽  
Fong-Zuo Lee
Keyword(s):  
Water Supply ◽  
Water Shortage ◽  
The Other ◽  
Engineering Construction ◽  
Flood Peak ◽  
Reservoir System ◽  
System A ◽  
Expected Benefits ◽  
The Impact

Abstract. A reservoir operator does not favor storage above a certain level in situations such as the pre-release operation prior to a flood; scheduled engineering construction; or mechanical excavation of sediment in the impoundments, drawdown, and empty flushing, etc. This paper selects empty flushing as the case study, and a method is presented to promote the feasibility of emptying the reservoir storage. The impact of emptying reservoir on water supply is minimized through appropriate joint operation in a multi-reservoir system, where drawdown and empty flushing is carried out in a primary reservoir, and the other reservoir provides backup water for supply. This method prioritizes allocating the storage in the primary reservoir for water supply during specific periods prior to its emptying. If the storage of every reservoir achieves its predefined conditions, drawdown of the primary reservoir is activated and followed by empty flushing. Previously preserved storage in the other reservoir ensures adequate water supply during the periods of emptying the primary reservoir. Flushing of the primary reservoir is continued until either the accumulative released water exceeds the specified volume, storage in the backup reservoir drops below the predefined threshold, or the inflow to the primary reservoir recedes from the flood peak to be below the releasing capacity of outlets. This behavior is simulated and linked with a nonlinear optimization algorithm to calibrate the optimal parameters defining the activation and termination of empty flushing. The optimized strategy limits the incremental water shortage within the acceptable threshold and maximizes the expected benefits of emptying reservoir.

Power generation scheduling through use of generalised network flow programming

1991 ◽  
Vol 138 (1) ◽  
pp. 39 ◽  
Author(s):  
R.E. Rice ◽  
W.M. Grady ◽  
W.G. Lesso ◽  
A.H. Noyola ◽  
M.E. Connolly
Keyword(s):  
Power Generation ◽  
Network Flow ◽  
Generation Scheduling ◽  
Network Flow Programming

Safe water, household income and health challenges in Ugandan homes that harvest rainwater

Water Policy ◽  
2012 ◽  
Vol 14 (6) ◽  
pp. 977-990 ◽  
Author(s):  
David Baguma ◽  
Jamal H. Hashim ◽  
Syed M. Aljunid ◽  
Michael Hauser ◽  
Helmut Jung ◽  
...  
Keyword(s):  
Water Supply ◽  
Health Risks ◽  
Water Shortage ◽  
Information Support ◽  
Household Expenditures ◽  
Safe Water ◽  
Influence Of Water ◽  
Supply Equipment

Having access to a safe water supply is important to improve a person's quality of life. We examine the relationship between the influence of water availability on monthly household expenditures (the dependent variable) and independent variables such as household characteristics, tank size, usage instructions and post-construction guidance, including the management of water-related health risks. The sample consisted of 301 respondents who harvest rainwater in Uganda. A multiple regression analysis was used to analyse the data. The findings show that post-construction guidance and tank size were significant variables. This study suggests the need for a follow-up to improve health after the installation of water supply equipment, i.e., to provide information about water risks, foster reading norms and facilitate the availability and affordability of information sources, e.g., subsidised newspapers and information support devices (computers). Additionally, this study shows the possibility of increased savings due to reduced expenditures on water from vendors and the management of water-related health risks caused by a water shortage, e.g., dehydration. Overall, the study reveals two possible ways to advance policy and health in developing countries: (1) ensuring sufficient post-construction guidance for all water resources; and (2) ensuring a sustainable supply of adequate safe water in households.

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