scholarly journals Optimal Multi-Reservoir Operation for Hydropower Production in the Nam Ngum River Basin

2020 ◽  
Vol 24 (5) ◽  
pp. 1-13
Author(s):  
Bounhome Kimmany ◽  
Piyatida Ruangrassamee ◽  
Supattra Visessri
Keyword(s):  
Water Balance ◽  
River Basin ◽  
Balance Equation ◽  
Optimization Model ◽  
Reservoir Operation ◽  
Water Balance Equation ◽  
Rule Curves ◽  
Minlp Model ◽  
Hydropower Production ◽  
Operation Rule

This research aims to investigate optimal hydropower production of multi-reservoirs in Lao PDR and develop optimal reservoir rule curves. The Nam Ngum 1 and 2 (NN1 and NN2, respectively) reservoirs in the Nam Ngum River basin (NNRB), which is located in the middle of Laos, are selected as study areas. Mixed integer nonlinear programming (MINLP) is developed as an optimization model to maximize the hydropower production of joint reservoir operation of NN1 and NN2. The optimal operation rule curves are established by using the storage level estimated by the optimization model. Given the limited sideflow data, an integrated flood analysis system (IFAS) and water balance equation are used to simulate the sideflow into NN1 reservoir. A good fit is observed between the monthly streamflow simulated by IFAS and that calculated by the water balance equation. Compared with the observed data, the MINLP model can increase the annual and monthly hydropower production by 20.22% (6.01% and 14.21% for NN1 and NN2, respectively). The water storage level estimated by the MINLP model is used to build the operation rule curves. Results show that the MINLP model of multi-reservoir is a useful and effective approach for multi-reservoir operations and is expected to hold high application value for similar reservoirs in NNRB.

scholarly journals Retention time of lakes in the Larsemann Hills oasis, East Antarctica

2020 ◽  
Author(s):  
Elena Shevnina ◽  
Ekaterina Kourzeneva ◽  
Yury Dvornikov ◽  
Irina Fedorova
Keyword(s):  
Water Balance ◽  
Retention Time ◽  
Balance Equation ◽  
Water Exchange ◽  
Warm Season ◽  
East Antarctica ◽  
Water Balance Equation ◽  
Larsemann Hills ◽  
Lake Volume ◽  
Field Campaigns

Abstract. The study gives first estimates of water transport scale for five lakes located in the Larsemann Hills oasis (69º23' S, 76º20' E) in the East Antarctica. We estimated the lake retention time (LRT) as a ratio of the lake volume to the income and outcome terms of a lake water balance equation. The LRT was evaluated for lakes of epiglacial and land-locked types, and it was assumed that these lakes are monomictic with water exchange existing during a warm season only. We used hydrological observations collected in 4 seasonal field campaigns to evaluate the LRT from the outcome and income terms of the water balance equation. For the epiglacial lakes Progress/LH57 and Nella/Scandrett/LH72, the LRT was estimated of 12–13 and 4–5 years, respectively. For the land-locked lakes Stepped/LH68, Sara Tarn/LH71 and Reid/LH70, our results show a big difference in the LRT calculated from the outcome and income components of the water balance equation. The LRT for these lakes vary depending on the methods and errors inherent to them. We suggested to rely on the estimations from the outcome surface runoff since they are based on the hydrological measurements with better quality. Lake Stepped/LH68 exchange water within less then 1.5 years. Lake Sara Tarn/LH71 and Lake Reid/LH70 are the endorheic ponds with the water exchange through mostly evaporation, their LRT was estimated as 21–22 years and from 8–9 years, respectively. To improve the estimates of the LRT, the hydrological observations are needed to monitor the lakes and streams during the warm season with the uniform observational program.

The Effectiveness of Evapotranspiration Systems in Disposing of Wastewater in Remote Aboriginal Communities in Northwest Australia

1991 ◽  
Vol 23 (10-12) ◽  
pp. 1825-1833
Author(s):  
D. R. McGrath ◽  
G. E. Ho ◽  
K. Mathew
Keyword(s):  
Water Balance ◽  
Water Loss ◽  
Balance Equation ◽  
Eucalyptus Camaldulensis ◽  
Bare Soil ◽  
Pan Evaporation ◽  
Aboriginal Communities ◽  
Water Balance Equation ◽  
Northwest Australia

The potential usage of Evapotranspiration (ET) systems in remote Aboriginal communities was investigated. ET system sizing requirements were determined from the water balance equation. Water loss from lysimeters planted with trees (Eucalyptus camaldulensis) or lawn grass and from bare soil and gravel was monitored over several months and compared to pan evaporation measured during the same period. It was found that ET from bare soil and grass followed similar trends to pan evaporation, ranging from 30-60% of pan evaporation for soil and from 60-80% of pan evaporation for grass. ET rates increased in the tanks planted with trees as the plants grew and exceeded pan evaporation rates. Evaporation from gravel-filled lysimeters was low, being as little as 10% of pan evaporation.

scholarly journals Global evapotranspiration over the past three decades: estimation based on the water balance equation combined with empirical models

2012 ◽  
Vol 7 (1) ◽  
pp. 014026 ◽  
Author(s):  
Zhenzhong Zeng ◽  
Shilong Piao ◽  
Xin Lin ◽  
Guodong Yin ◽  
Shushi Peng ◽  
...  
Keyword(s):  
Water Balance ◽  
Balance Equation ◽  
Empirical Models ◽  
Water Balance Equation ◽  
The Past

Stochastic Modeling of Aquifer Level Temporal Fluctuations Based on the Conceptual Basis of the Soil-Water Balance Equation

Soil Science ◽  
2016 ◽  
Vol 181 (6) ◽  
pp. 224-231 ◽  
Author(s):  
Emmanouil A. Varouchakis ◽  
Katerina Spanoudaki ◽  
Dionissios T. Hristopulos ◽  
George P. Karatzas ◽  
Gerald A. Corzo Perez
Keyword(s):  
Water Balance ◽  
Soil Water ◽  
Stochastic Modeling ◽  
Balance Equation ◽  
Soil Water Balance ◽  
Conceptual Basis ◽  
Water Balance Equation ◽  
Temporal Fluctuations

Soil water balance and evapotranspiration of irrigated cotton

1967 ◽  
Vol 69 (1) ◽  
pp. 95-101 ◽  
Author(s):  
W. R. Stern
Keyword(s):  
Soil Moisture ◽  
Water Balance ◽  
Soil Water ◽  
Balance Equation ◽  
Dry Season ◽  
Soil Water Balance ◽  
Wet Season ◽  
Water Balance Equation ◽  
Soil Moisture Storage ◽  
Moisture Storage

In a series of five irrigated cotton sowings (T2, T7, T9, T11, T14) evapotranspiration (Et) was determined for the period between October 1961 and October 1962 by observing frequently the changes in soil moisture storage, calculating through drainage, and solving for evapotranspiration in the water balance equation. Thus a water balance was obtained for each sowing extending over the entire crop.The average evapotranspiration in wet season sowings was of the order of 6·5 mm day−1 and in dry season sowings of the order of 4·5 mm day−1. The highest evapotranspiration values ranged between 10 and 12 mm day−1 in T2, T7 and T9 and between 7 and 9·5 mm day−1 in T11 and T14.

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