scholarly journals Modified frequency computation method for optimal environmental flows

2012 ◽  
Vol 16 (5) ◽  
pp. 1539-1543 ◽  
Author(s):  
Zhen-Hui Dong ◽  
Xiao-Hua Yang ◽  
Ya-Nan Guo ◽  
Ying Mei ◽  
Yu-Qi Li ◽  
...  
Keyword(s):  
Environmental Flows ◽  
Computation Method ◽  
Flow Method ◽  
Lancang River ◽  
Ecological Flow ◽  
Tennant Method

The paper describes a modified frequency computation method to calculate the optimal environmental flows. This method was used to design monthly environmental flows in Lancang river. The environmental flows calculated by the method are compared with those by the ecological flow method and the Tennant method, revealing its effectiveness.

scholarly journals A new method for calculating ecological flow: Distribution flow method

AIP Advances ◽  
2018 ◽  
Vol 8 (4) ◽  
pp. 045118 ◽  
Author(s):  
Guangming Tan ◽  
Ran Yi ◽  
Jianbo Chang ◽  
Caiwen Shu ◽  
Zhi Yin ◽  
...  
Keyword(s):  
Flow Distribution ◽  
New Method ◽  
Flow Method ◽  
Ecological Flow

Determining effect of the Land Consolidation Project on Cropland ecosystem based on ecological flow method

2015 ◽  
Vol 35 (23) ◽  
Author(s):  
郭贝贝 Guo Beibei ◽  
金晓斌 Jin Xiaobin ◽  
林忆南 Lin Yinan ◽  
杨绪红 Yang Xuhong ◽  
周寅康 Zhou Yinkang
Keyword(s):  
Land Consolidation ◽  
Flow Method ◽  
Ecological Flow ◽  
Cropland Ecosystem ◽  
Land Consolidation Project

scholarly journals Characteristics and Adaptability Assessment of Commonly Used Ecological Flow Methods in Water Storage and Hydropower Projects, the Case of Chinese River Basins

Water ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 2035
Author(s):  
Lejun Ma ◽  
Huan Wang ◽  
Changjun Qi ◽  
Xinnan Zhang ◽  
Hanwen Zhang
Keyword(s):  
River Basin ◽  
Yellow River ◽  
Yangtze River Basin ◽  
Water Storage ◽  
Yellow River Basin ◽  
River Basins ◽  
Average Flow ◽  
Ecological Flow ◽  
Tennant Method ◽  
Rate Method

The construction and operation of water storage and hydropower projects affects the structure of water ecosystems of downstream rivers, and the establishment of ecological flow in rivers below the water storage and hydropower projects has significant impacts on maintaining the stability of river ecosystems. A database was established based on 2000–2017 environmental impact assessment (EIA) reports on water storage and hydropower projects in China and ecological flow (e-flow) methods, and the three widely used e-flow methods for water storage and hydropower projects in China were identified on the database. Furthermore, an ecological flow satisfaction degree model was used to evaluate the methods using long series of historical hydrological data from the hydrological stations in the Yellow River basin, the Yangtze River basin, and the Liao River basin. The results showed that hydrological methods are the type most often used for water storage and hydropower projects in China, including the Tennant method, the minimum monthly average flow with 90% guarantee rate method (Mm9M method), and the measured historical minimum daily average flow rate method (MDM method). However, the ecological flow methods selected are not significantly different among different basins, indicating that the selection of ecological flow methods is rather arbitrary, and adaptability analysis is not available. The results of the ecological flow satisfaction model showed that the Tennant method is not suitable for large river basins. The results of this study can provide technical support for establishment and management decisions surrounding ecological flow.

An instream ecological flow method for data-scarce regulated rivers

2011 ◽  
Vol 398 (1-2) ◽  
pp. 17-25 ◽  
Author(s):  
Changming Liu ◽  
Changsen Zhao ◽  
Jun Xia ◽  
Changlei Sun ◽  
Rui Wang ◽  
...  
Keyword(s):  
Regulated Rivers ◽  
Flow Method ◽  
Ecological Flow

scholarly journals A Method for Solving Percolation Overflow Boundary Based on Maximum of Horizontal Energy Loss Rate

2021 ◽  
Vol 9 ◽  
Author(s):  
Yuandong Li ◽  
Bing Hao ◽  
Xiaojun Li ◽  
Liguo Jin ◽  
Qing Dong ◽  
...  
Keyword(s):  
Energy Loss ◽  
Loss Rate ◽  
Computation Method ◽  
Dimensional Model ◽  
Seepage Field ◽  
Initial Flow ◽  
Energy Loss Rate ◽  
Flow Method ◽  
Maximum Value ◽  
Element Method

The determination of overflow boundary is a prerequisite for the accurate solution of the seepage field by the finite element method. In this paper, a method for solving overflow boundary according to the maximum value of horizontal energy loss rate is proposed, which based on the analysis of the physical meaning of functional and the water head distribution of seepage field under different overflow boundaries. This method considers that the overflow boundary that makes the horizontal energy loss rate reach the maximum value is the real boundary overflow. Compared with the previous iterative computation method of overflow point and free surface, the method of solving overflow boundary based on the maximum horizontal energy loss rate does not need iteration, so the problem of non-convergence does not exist. The relative error of the overflow points is only 1.54% and 0.98% by calculating the two-dimensional model of the glycerol test and the three-dimensional model of the electric stimulation test, respectively. Compared with the overflow boundary calculated by the node virtual flow method, improved cut-off negative pressure method, initial flow method, and improved discarding element method, this method has a higher accuracy.

scholarly journals Calculation of the Instream Ecological Flow of the Wei River Based on Hydrological Variation

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Shengzhi Huang ◽  
Jianxia Chang ◽  
Qiang Huang ◽  
Yimin Wang ◽  
Yutong Chen
Keyword(s):  
Sustainable Development ◽  
Adaptation Theory ◽  
River Ecosystems ◽  
The Sustainable Development ◽  
Healthy Development ◽  
Ecological Flow ◽  
Calculation Results ◽  
Tennant Method ◽  
Hydrological Variation ◽  
The Law

It is of great significance for the watershed management department to reasonably allocate water resources and ensure the sustainable development of river ecosystems. The greatly important issue is to accurately calculate instream ecological flow. In order to precisely compute instream ecological flow, flow variation is taken into account in this study. Moreover, the heuristic segmentation algorithm that is suitable to detect the mutation points of flow series is employed to identify the change points. Besides, based on the law of tolerance and ecological adaptation theory, the maximum instream ecological flow is calculated, which is the highest frequency of the monthly flow based on the GEV distribution and very suitable for healthy development of the river ecosystems. Furthermore, in order to guarantee the sustainable development of river ecosystems under some bad circumstances, minimum instream ecological flow is calculated by a modified Tennant method which is improved by replacing the average flow with the highest frequency of flow. Since the modified Tennant method is more suitable to reflect the law of flow, it has physical significance, and the calculation results are more reasonable.

scholarly journals The California Environmental Flows Framework: Meeting the Challenges of Developing a Large-Scale Environmental Flows Program

2021 ◽  
Vol 9 ◽  
Author(s):  
Eric D. Stein ◽  
Julie Zimmerman ◽  
Sarah M. Yarnell ◽  
Bronwen Stanford ◽  
Belize Lane ◽  
...  
Keyword(s):  
Large Scale ◽  
Environmental Flows ◽  
Spatial Scales ◽  
Environmental Flow ◽  
The State ◽  
Rate Of Change ◽  
Inclusive Development ◽  
Initial Flow ◽  
Implementation Challenges ◽  
Ecological Flow

Environmental flow programs aim to protect aquatic habitats and species while recognizing competing water demands. Often this is done at the local or watershed level because it is relatively easier to address technical and implementation challenges at these scales. However, a consequence of this approach is that ecological flow criteria are developed for only a few areas as dictated by funding and interest with many streams neglected. Here we discuss the collaborative development of the California Environmental Flows Framework (CEFF) as an example process for developing environmental flow recommendations at a statewide scale. CEFF uses a functional flows approach, which focuses on protecting a broad suite of ecological, geomorphic, and biogeochemical functions instead of specific species or habitats, and can be applied consistently across diverse stream types and spatial scales. CEFF adopts a tiered approach in which statewide models are used to estimate ecological flow needs based on natural functional flow ranges, i.e., metrics that quantify the required magnitude, timing, duration, frequency, and/or rate-of-change of functional flow components under reference hydrologic conditions, for every stream reach in the state. Initial flow needs can then be revised at regional, or watershed, scales based on local constraints, management objectives, and available data and resources. The third tier of CEFF provides a process for considering non-ecological flow needs to produce a final set of environmental flow recommendations that aim to balance of all desired water uses. CEFF was developed via a broad inclusive process that included technical experts across multiple disciplines, representatives from federal and state agencies, and stakeholders and potential end-users from across the state. The resulting framework is therefore not associated with any single agency or regulatory program but can be applied under different contexts, mandates and end-user priorities. The inclusive development of CEFF also allowed us to achieve consensus on the technical foundations and commitment to applying this approach in the future.

A New Ecological Flow Assessment Method Based on Spatial-Temporal Variability and Transferability

2014 ◽  
Vol 522-524 ◽  
pp. 791-794 ◽  
Author(s):  
Chang Wen Li ◽  
Ling Kang
Keyword(s):  
Spatial Variation ◽  
Temporal Variability ◽  
Assessment Method ◽  
New Approach ◽  
Ecological Flow ◽  
Tennant Method ◽  
The Mean ◽  
Hanjiang River ◽  
Ecological Objectives

To solve transferability and spatial-temporal variability problems of ecological flow (EF) criteria existed in traditional Tennant methods, a new modified Tennant method was proposed. Considering the temporal variability and influence of extreme flows on average annual flow, the EF criteria for every month and water year were set as variables, and median monthly flow was taken as the optimum EF ceiling. Considering transferability and spatial variation of ecological objectives in different water function zones, the mean of monthly flow under 95% guaranteed rate and minimum monthly flow was used as the minimum EF. To avoid arbitrary use of EF criteria at all levels, the idea of arithmetic progression was introduced. On achieving satisfactory verification, the new approach was applied in the Hanjiang River as a case study. It is found that this new approach is reasonable with excellent spatial-temporal variability.

scholarly journals STUDY ON METHODS OF DETERMINATION OF AN ECOLOGICAL FLOW FOR THE MANAGEMENT OF WATER RESOURCES OF THE RIVER BASIN ON MARACAÇUMÉ RIVER

2018 ◽  
Vol 15 (30) ◽  
pp. 27-34
Author(s):  
L. S. ROSA JUNIOR ◽  
H. S. ALMEIDA ◽  
S. C. S. A. BRASIL ◽  
A. B. P. DE MORAIS ◽  
J. B. SARAIVA ◽  
...  
Keyword(s):  
Water Resources ◽  
River Basin ◽  
Water Availability ◽  
Sustainable Management ◽  
Flow Regimes ◽  
Maximum Percentage ◽  
Ecological Flow ◽  
Tennant Method

The elaboration of a study on methods for the determination of ecological flow for the management of the water resources of the Maracaçumé River Basin is very important for the proposed use and conservation of these resources insofar as the uses of water, especially the advisory uses, have changed the flow regimes and the existing water availability. In this context, this work aims to discuss about the applicability of hydrological methods that help in the correct and sustainable management of the water resources. In this way, were applied theQ7,10 Method; the 90% and 95% Method, beyond the Tennant Method with ecological flow corresponding to 30% of the average annual flow. The main results obtained were the characterization of the Maracaçumé River Basin and the flow values obtained in each method (0.541 m3/s, 1,075 m3/s, 0,459 m3/s and 19,50 m3/s for the Q7,10; Q90%; Q95% and Tennant (30%) methods, respectively). The work indicates that for the management of water resources in the Maracaçumé river basin, the ecological flow obtained through the Q90 methodology should continue to be adopted, evaluating the possibility of adapting the maximum percentage of use.

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