Application of Multiple Environmental Flow Methods to Optimize Cascade Dams Operation in the Lower Jinsha River

2014 ◽  
Vol 955-959 ◽  
pp. 3057-3064
Author(s):  
Zheng Jie Yin ◽  
Jin Chen ◽  
Ji Jun Xu

To mitigate possible negative impacts of cascade dams in the Lower Jinsha River and maintain the natural flow regime of national natural reserve areas of rare and special fishes of the upper Yangtze River, environmental flow (e-flow) demands need to be considered in the cascade dams operation. Due to lack of regular ecological observation data, multiple hydrology-based e-flow methods including Tennant, minimum monthly flow, 7Q10 and Q90 are applied to provide specific e-flow prescripts to guide the reservoir release. A joint operation optimization model is developed for the cascade dams in the Lower Jinsha River for maximal hydropower generation under various e-flow constraints. The economic and ecological performances of cascade dams operation are evaluated by total hydropower outputs and hydrological alteration degree of downstream river individually. The operation results are analyzed and discussed, and some questions on the tradeoff relationship between ecology and hydropower generation, inherent relationship between ecological constrains and hydrological alteration, and rationality criteria of e-flow are further addressed. The conclusions indicate : (1) optimal operation for ecological considerations under e-flow constrains only reduce hydropower outputs slightly, no more than 2.4%; (2) e-flow constrains help lower hydrological alteration induced by hydropower dams, among the four e-flow methodologies Tennant is best in term of ecology; (3) there is a limitation for hydrology-based e-flow methodologies, and it is necessary to stress ecological foundation and ecological relevance for e-flow methodology. The paper will provide technical references for future ecological re-operation of the cascade dams.

2021 ◽  
Author(s):  
Siqi Tong ◽  
Silke Wieprecht ◽  
Martin Schletterer

<p>This study was carried out in the middle and lower reaches of the Jinsha River in southwest China, which represents the upper Yangtze River. Hydraulic structures (14 cascade hydropower stations) are planned and/or constructed in this system, which is considered as largest hydropower base. We aim to summarize appropriate measures to restore the riverine continuum in the middle and lower reaches of the Jinsha River, where high-head cascade hydropower dams are located or planned.</p><p>We distributed a questionnaire to Chinese researchers in the related fields (scientists, hydropower operators and NGOs in China, n = 60). According to the responses, fishways, fish lift, fish lock, trap-and-truck system as well as fish hatcheries (artificial breeding) are recognized to ensure passing respectively preserving fish in the Jinsha River basin.</p><p>A longitudinal connectivity assessment of the study area revealed a severely disturbed continuity status. Based on the biological analyses of the demands of the target fish species and review of fish pass technologies, a vertical-slot fishway is proposed.</p><p>Considering the dam heights and the geographical conditions, it is recommended to combine the vertical-slot fishway with these alternatives to achieve a higher efficiency in passing fish as well as to recover the river continuity towards regional sustainable development.</p>


Water ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 115 ◽  
Author(s):  
Roxelane Cakir ◽  
Mélanie Raimonet ◽  
Sabine Sauvage ◽  
Javier Paredes-Arquiola ◽  
Youen Grusson ◽  
...  

Modeling is a useful way to understand human and climate change impacts on the water resources of agricultural watersheds. Calibration and validation methodologies are crucial in forecasting assessments. This study explores the best calibration methodology depending on the level of hydrological alteration due to human-derived stressors. The Soil and Water Assessment Tool (SWAT) model is used to evaluate hydrology in South-West Europe in a context of intensive agriculture and water scarcity. The Index of Hydrological Alteration (IHA) is calculated using discharge observation data. A comparison of two SWAT calibration methodologies are done; a conventional calibration (CC) based on recorded in-stream water quality and quantity and an additional calibration (AC) adding crop managements practices. Even if the water quality and quantity trends are similar between CC and AC, water balance, irrigation and crop yields are different. In the context of rainfall decrease, water yield decreases in both CC and AC, while crop productions present opposite trends (+33% in CC and −31% in AC). Hydrological performance between CC and AC is correlated to IHA: When the level of IHA is under 80%, AC methodology is necessary. The combination of both calibrations appears essential to better constrain the model and to forecast the impact of climate change or anthropogenic influences on water resources.


Energies ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 144 ◽  
Author(s):  
Jianjian Shen ◽  
Xiufei Zhang ◽  
Jian Wang ◽  
Rui Cao ◽  
Sen Wang ◽  
...  

This paper focuses on the monthly operations of an interprovincial hydropower system (IHS) connected by ultrahigh voltage direct current lines. The IHS consists of the Xiluodu Hydropower Project, which ranks second in China, and local plants in multiple recipient regions. It simultaneously provides electricity for Zhejiang and Guangdong provinces and thus meets their complex operation requirements. This paper develops a multi-objective optimization model of maximizing the minimum of total hydropower generation for each provincial power grid while considering network security constraints, electricity contracts, and plant constraints. The purpose is to enhance the minimum power in dry season by using the differences in hydrology and regulating storage of multiple rivers. The TOPSIS method is utilized to handle this multi-objective optimization, where the complex minimax objective function is transformed into a group of easily solved linear formulations. Nonlinearities of the hydropower system are approximatively described as polynomial formulations. The model was used to solve the problem using mixed integer nonlinear programming that is based on the branch-and-bound technique. The proposed method was applied to the monthly generation scheduling of the IHS. Compared to the conventional method, both the total electricity for Guangdong Power Grid and Zhejiang Power Grid during dry season increased by 6% and 4%, respectively. The minimum monthly power also showed a significant increase of 40% and 31%. It was demonstrated that the hydrological differences between Xiluodu Plant and local hydropower plants in receiving power grids can be fully used to improve monthly hydropower generation.


2014 ◽  
Vol 641-642 ◽  
pp. 226-231 ◽  
Author(s):  
Bing Yu Chen ◽  
Hui Huang Luo ◽  
Qing Rui Yang ◽  
Wei Huang ◽  
Hui Ling Han

The upper Yangtze river rare and endemic national nature reserve was set up to protect the rare and endemic fish. Affected by the cascade development of the downstream reach of the jinsha river, fish habitat in the national nature reserve have been changed significantly, which will affect the reproduction and growth of the fishes.The Coreius heterodon spawning grounds were located in the Main stream of the natural reserve, andits spawning season needs certain overflowing process to lay eggs. This article used the water level and flow data from 1956 to 2012 in the Zhu Tuo stationto analysis the eco-hydrologicaldemand for Coreiusheterodon breeding. and this result can provide the reference for the ecological operation of cascade reservoirs in the downstreamof jinsha river.


Water ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1250 ◽  
Author(s):  
Chao Zhou ◽  
Na Sun ◽  
Lu Chen ◽  
Yi Ding ◽  
Jianzhong Zhou ◽  
...  

The purpose of a flood control reservoir operation is to prevent flood damage downstream of the reservoir and the safety of the reservoir itself. When a single reservoir cannot provide enough storage capacity for certain flood control points downstream, cascade reservoirs should be operated together to protect these areas from flooding. In this study, for efficient use of the reservoir storage, an optimal flood control operation model of cascade reservoirs for certain flood control points downstream was proposed. In the proposed model, the upstream reservoirs with the optimal operation strategy were considered to reduce the inflow of the reservoir downstream. For a large river basin, the flood routing and time-lag cannot be neglected. So, dynamic programming (DP) combined with the progressive optimality algorithm (POA) method, DP-POA, was proposed. Thus, the innovation of this study is to propose a two-stage optimal reservoir operation model with a DP-POA algorithm to solve the problem of optimal co-operation of cascade reservoirs for multiple flood control points downstream during the flood season. The upper Yangtze River was selected as a case study. Three reservoirs from upstream to downstream, Xiluodu, Xiangjiaba and the Three Gorges reservoirs (TGR) in the upper Yangtze River, were taken into account. Results demonstrate that the two-stage optimization algorithm has a good performance in solving the cascade reservoirs optimization problem, because the inflow of reservoir downstream and the division volumes were largely reduced. After the optimal operation of Xiluodu and Xiangjiaba reservoirs, the average reduction of flood peak for all these 13 typical flood hydrographs (TFHs) is 13.6%. Meanwhile, the cascade reservoirs can also store much more storm water during a flood event, and the maximum volumes stored in those two reservoirs upstream in this study can reach 25.2 billion m3 during a flood event. Comprising the proposed method with the current operation method, results demonstrate that the flood diversion volumes at the flood control points along the river decrease significantly.


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