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The rapid economic development of river basins depends on the excessive use of water resources. China experienced a rapid development of hydropower projects in the last two decades and thus faces many ecological and environmental issues, especially in ecologically sensitive areas. Environmental flow is an important management tool that requires attention in the environmental impact assessment of hydropower projects. Environmental flows are of great significance for maintaining river structures and protecting the health of both aquatic ecosystems and human sustainable livelihoods. Although the government authorities have done much work in this area and attempted to consider technical requirements to address the negative externalities of hydropower projects, there are still defects in the basic procedures, calculation methods, and ultimately implementation process from policy to operationalization in terms of environmental flows. The official standards for environmental flows assessment mainly appear in two documents: 1. specification for calculation of environmental flow in rivers and lakes; and 2. code for calculation ecological flow of hydropower projects. This paper reviewed the overarching framework of the two documents and then summarized their fitness in terms of environmental flows implementation in hydropower projects. The research status of environmental flows and future directions for China were also proposed in this paper.
Miao Wu; Ang Chen; Xingnan Zhang; Michael E. McClain. A Comment on Chinese Policies to Avoid Negative Impacts on River Ecosystems by Hydropower Projects. Water 2020, 12, 869 .
AMA StyleMiao Wu, Ang Chen, Xingnan Zhang, Michael E. McClain. A Comment on Chinese Policies to Avoid Negative Impacts on River Ecosystems by Hydropower Projects. Water. 2020; 12 (3):869.
Chicago/Turabian StyleMiao Wu; Ang Chen; Xingnan Zhang; Michael E. McClain. 2020. "A Comment on Chinese Policies to Avoid Negative Impacts on River Ecosystems by Hydropower Projects." Water 12, no. 3: 869.
The implementation of environmental flows is of the utmost importance for ecosystem protection and restoration in dammed rivers. A key challenge in optimizing dam regulation is the uncertainty of the ecohydrology relationship between flow release and ecological response. In the present paper, we develop a framework of dam classification to organize the categories of the ecohydrology relationship for implementing environmental flows. Dams are classified from three major categories that differ in dam properties, hydrological alteration, and downstream hydrobiological diversities based on the relationship of hydrology and ecology. Finally, 773 dams in China are screened and ranked into four classes involving a great diversity of environmental flow components. A classification of dams that utilizes the implementation of environmental flows is presented. (1) Class 1 includes dams with rare and endangered fish species in the downstream. It is the category with the highest priority for environmental flow releases and regulation, requiring continuous flow and flood pulse components for fish spawning and migration. (2) Class 2 includes dams with significant hydrological alteration in the downstream. It is the category with second priority for environmental flow releases and regulation, requiring natural hydrological regimes simulation or complete flow component recovery for optimizing the flow duration curve and mitigating adverse impacts of dam operation. (3) Class 3 includes dams with a high degree of regulation where there is urgency for environmental flow releases and regulation, requiring that minimum flow is guaranteed by cascade reservoir regulation. (4) Class 4 includes dams with a low degree of regulation where there is less urgency for environmental flow releases and regulation. This classification method is important for future research, including environmental flow release regulation and the effectiveness evaluation of environmental flow adaptive management. It will be useful for guiding the implementation of environmental flows.
Ang Chen; Miao Wu; Michael E. McClain. Classifying Dams for Environmental Flow Implementation in China. Sustainability 2019, 12, 107 .
AMA StyleAng Chen, Miao Wu, Michael E. McClain. Classifying Dams for Environmental Flow Implementation in China. Sustainability. 2019; 12 (1):107.
Chicago/Turabian StyleAng Chen; Miao Wu; Michael E. McClain. 2019. "Classifying Dams for Environmental Flow Implementation in China." Sustainability 12, no. 1: 107.
Environmental flows (e-flows) are important for river protection and restoration under degraded ecological conditions. With increasing public desire for and pursuit of sustainable development, e-flows are widely used to reflect the hydrological regime requirements for sustaining freshwater ecosystems and human livelihoods. Over the past 40 years, e-flows implementation has shifted from static minimum flows to dynamic flow components. However, e-flows standards used to manage flow releases from dams are to a great extent based on expert judgement and government supervision. These attributes make it difficult to effectively implement e-flows in the non-stationary world. The primary focus of this paper is to review the history, management systems and scientific basis of e-flows in China. Firstly, the study classifies the development phases into four periods and then analyses the underpinning legal system for e-flows implementation in each period, including the laws, regulations, policies and responsible authorities. Finally, the scientific basis and methods for e-flows determination and assessment were analyzed. The study showed that: (1) e-flows have been officially regarded as ecological flow in China, which evolved from minimum flow, and the contents and connotations are still broadening; (2) currently, there are too many authorities related to e-flows and complicated legal documents in China which lead to ineffective implementation; (3) the scientific basis of e-flows is enriched from the relationship between hydrological alteration and ecological response, so that the practices will be more holistic in China. Despite the successful practices of e-flows implementation in large rivers, there are challenges for implementing future e-flows in small rivers. This study recommended that future e-flows implementation be integrated with sustainable water management by setting clear responsibilities for governments, ministries, and other stakeholders.
Ang Chen; Miao Wu. Managing for Sustainability: The Development of Environmental Flows Implementation in China. Water 2019, 11, 433 .
AMA StyleAng Chen, Miao Wu. Managing for Sustainability: The Development of Environmental Flows Implementation in China. Water. 2019; 11 (3):433.
Chicago/Turabian StyleAng Chen; Miao Wu. 2019. "Managing for Sustainability: The Development of Environmental Flows Implementation in China." Water 11, no. 3: 433.
The histone acetyltransferase males-absent-on-the-first (MOF) acetylates the histone H4, a modification important for many biological processes, including chromatin organization, transcriptional regulation, DNA replication, recombination and repair, as well as autophagy. Depletion of MOF induces serious consequences because of the reduction of histone acetylation, such as nuclear morphological defects and cancer. Despite the critical roles of MOF in the nucleus, the structural or functional mechanisms of the nucleocytoplasmic transport of MOF remain elusive. Here, we identified novel importin α1-specific nuclear localization signals (NLSs) in the N-terminal of human MOF. The crystal structure of MOF NLSs in complex with importin α1 further revealed a unique binding mode of MOF, with two independent NLSs binding to importin α1 major and minor sites, respectively. The second NLS of MOF displays an unexpected α-helical conformation in the C-terminus, with more extensive contacts with importin α1 not limited in the minor site. Mutations of the key residues on MOF and importin α1 lead to the reduction of their interaction as well as the nuclear import of MOF, revealing an essential role of NLS2 of MOF in interacting with importin α1 minor site. Taken together, we provide structural mechanisms underlying the nucleocytoplasmic transport of MOF, which will be of great importance in understanding the functional regulation of MOF in various biological processes.
Weili Zheng; Siyu Tian; Benqiang Yao; Ang Chen; Shikai Jin; Rui Wang; Xi Liu; Yong Li. Structural insights into the nuclear import of the histone acetyltransferase males-absent-on-the-first by importin α1. Traffic 2017, 19, 19 -28.
AMA StyleWeili Zheng, Siyu Tian, Benqiang Yao, Ang Chen, Shikai Jin, Rui Wang, Xi Liu, Yong Li. Structural insights into the nuclear import of the histone acetyltransferase males-absent-on-the-first by importin α1. Traffic. 2017; 19 (1):19-28.
Chicago/Turabian StyleWeili Zheng; Siyu Tian; Benqiang Yao; Ang Chen; Shikai Jin; Rui Wang; Xi Liu; Yong Li. 2017. "Structural insights into the nuclear import of the histone acetyltransferase males-absent-on-the-first by importin α1." Traffic 19, no. 1: 19-28.
In this study, 96 Environmental Impact Assessment (EIA) reports of hydropower projects from 2001 to 2015 have been collected, and four parts of the contents including the project status, hydrological characteristics, downstream fish status and ecological flow have been analyzed by statistical methods. Thus, we built the ecological flow database of hydropower projects in China, and analyzed the differences of ecological flow release before and after the implementation of the 2006 guideline, based on spatial and temporal characteristics analysis in ArcGIS platform. We also analyzed differences between the calculation methods, release types, safeguard measures and monitoring measures of ecological flow. Meanwhile, we analyzed the ecological benefits of insurance for endangered fish protection. We focused on the effectiveness of ecological flow guarantee and shortages after the 2006 guideline. Therefore, ecological flow practices on hydropower projects in China have been summarized, and we suggested 17% of annual average flow as the ecological flow constraint red line, combined with the flow process demand. Then we put forward the prospect of ecological flow research and practice in China, by strengthening the research of calculation principles, cascade reservoir operation and ecosystem recovery and rehabitation.
Miao Wu; Ang Chen. Practice on ecological flow and adaptive management of hydropower engineering projects in China from 2001 to 2015. Hydrology Research 2017, 20, 336 -354.
AMA StyleMiao Wu, Ang Chen. Practice on ecological flow and adaptive management of hydropower engineering projects in China from 2001 to 2015. Hydrology Research. 2017; 20 (2):336-354.
Chicago/Turabian StyleMiao Wu; Ang Chen. 2017. "Practice on ecological flow and adaptive management of hydropower engineering projects in China from 2001 to 2015." Hydrology Research 20, no. 2: 336-354.
Many hydrological algorithms have been developed to automatically extract drainage networks from DEM, and the D8 algorithm is widely used worldwide to delineate drainage networks and catchments. The simulation accuracy of the SWAT model depends on characteristics of the watershed, and previous studies of DEM resolution and its impacts on drainage network extraction have not generally considered the effects of resolution and threshold value on uncertainty. In order to assess the influence of different DEM resolutions and drainage threshold values on drainage network extraction using the SWAT model, 10 basic watershed regions in China were chosen as case studies to analyse the relationship between extracted watershed parameters and the threshold value. SRTM DEM data at 3 different resolutions were used in this study, and regression analysis for DEM resolution, threshold value and extraction effects was done. The results show that DEM resolution influences the selected flow accumulation threshold value; the suitable flow accumulation threshold value increases as the DEM resolution increases, and shows greater variability for basins with lower drainage densities. The link between drainage area threshold value and stream network extraction results was also examined, and showed a variation trend of power function y = axb between the sub-basin counts and threshold value, i.e., the maximum reach length increases while the threshold value increases, and the minimum reach length shows no relation with the threshold value. The stream network extraction resulting from a 250 m DEM resolution and a 50 000 ha threshold value was similar to the real stream network. The drainage network density and the threshold value also shows a trend of power function y = axb ; the value of b is usually 0.5.Keywords: SWAT, digital elevation model (DEM), watershed delineation, threshold value
Miao Wu; Peng Shi; Ang Chen; Chen Shen; Pengyuan Wang. Impacts of DEM resolution and area threshold value uncertainty on the drainage network derived using SWAT. Water SA 2017, 43, 450 .
AMA StyleMiao Wu, Peng Shi, Ang Chen, Chen Shen, Pengyuan Wang. Impacts of DEM resolution and area threshold value uncertainty on the drainage network derived using SWAT. Water SA. 2017; 43 (3):450.
Chicago/Turabian StyleMiao Wu; Peng Shi; Ang Chen; Chen Shen; Pengyuan Wang. 2017. "Impacts of DEM resolution and area threshold value uncertainty on the drainage network derived using SWAT." Water SA 43, no. 3: 450.
In this paper, we generally summarize the main issues in the operational period of water conservancy and hydropower projects in China over the past several decades. First, the adverse impacts of these projects since the technical guidelines were proposed in 2006 are analyzed. Then, combined with projects and experience from 2006 to 2014, the four main issues are summarized: (1) There exist many questions in the design and construction of fishways, which are useful for fish migration, and the migration effects are not as expected. (2) Temperature stratification affecting the downstream fish is the major impact of temperature, and alters fish spawning in the reproduction season. (3) Ecological base flow has been one of the primary questions of the last 30 years in China, the greatest related difficulty being quantification of the amount and flow process necessary to satisfy fish life history. (4) Fish habitat protection and restoration are popular topics in recent years with the development of river ecosystem restoration. Fish habitat loss due to the impacts of dam construction and habitat fragmentation has become more and more serious. These four issues are now the main difficulties in water project management, and interact with one another to bear combined effects on river ecosystems. The issues of eco-hydraulic consideration in the design period are the key factors. Finally, future priorities for research and practice of environmental protection for water conservancy and hydropower projects in China are proposed. The main purpose of this paper is to enhance the scientific research, monitoring, and assessment of operating effectiveness
Ang Chen; Miao Wu; Kai-Qi Chen; Zhi-Yu Sun; Chen Shen; Peng-Yuan Wang. Main issues in research and practice of environmental protection for water conservancy and hydropower projects in China. Water Science and Engineering 2016, 9, 312 -323.
AMA StyleAng Chen, Miao Wu, Kai-Qi Chen, Zhi-Yu Sun, Chen Shen, Peng-Yuan Wang. Main issues in research and practice of environmental protection for water conservancy and hydropower projects in China. Water Science and Engineering. 2016; 9 (4):312-323.
Chicago/Turabian StyleAng Chen; Miao Wu; Kai-Qi Chen; Zhi-Yu Sun; Chen Shen; Peng-Yuan Wang. 2016. "Main issues in research and practice of environmental protection for water conservancy and hydropower projects in China." Water Science and Engineering 9, no. 4: 312-323.
Lu Cao; Rui-Feng Liang; You-Cai Tuo; Yong Li; Ke-Feng Li; Ang Chen; Miao Wu; Kai-Qi Chen; Zhi-Yu Sun; Chen Shen. Influence of total dissolved gas-supersaturated water on silver carp (Hypophthalmichthys molitrix). Water Science and Engineering 2016, 9, 324 -328.
AMA StyleLu Cao, Rui-Feng Liang, You-Cai Tuo, Yong Li, Ke-Feng Li, Ang Chen, Miao Wu, Kai-Qi Chen, Zhi-Yu Sun, Chen Shen. Influence of total dissolved gas-supersaturated water on silver carp (Hypophthalmichthys molitrix). Water Science and Engineering. 2016; 9 (4):324-328.
Chicago/Turabian StyleLu Cao; Rui-Feng Liang; You-Cai Tuo; Yong Li; Ke-Feng Li; Ang Chen; Miao Wu; Kai-Qi Chen; Zhi-Yu Sun; Chen Shen. 2016. "Influence of total dissolved gas-supersaturated water on silver carp (Hypophthalmichthys molitrix)." Water Science and Engineering 9, no. 4: 324-328.
Wetlands are important habitats on biodiversity protection. In this study, the relationship between wetland and avifauna changes in the Yellow River Delta Wetland was studied. Remote sensing and geographic information system provided an advanced platform for the research. After the avifauna survey was performed from 2012 to 2013, the birds’ variation and driving factors were analyzed. The results showed that the flow into the wetland increased continuously from 2000, and the increased of artificial wetland prevented the wetland degradation, although at the same time the total wetland area decreased. Medium grassland, tidal flat and pond are the three main landscapes which are beneficial for the habitation of birds. The migrating numbers of red-crowned crane increased significantly from 2005, and the overwintering numbers increased from 2009. The study results show that the key land use types for protecting endangered species of birds are medium grassland, tidal flat and pond landscapes. Wetland changes are sensitive to the birds and significantly affected by the flow. We suggest that the artificial wetland project should enhance the three land use type area to ensure the wetland restoration.
Ang Chen; Xin Sui; Dongsheng Wang; Wengen Liao; Huaifeng Ge; Jie Tao. Landscape and avifauna changes as an indicator of Yellow River Delta Wetland restoration. Ecological Engineering 2015, 86, 162 -173.
AMA StyleAng Chen, Xin Sui, Dongsheng Wang, Wengen Liao, Huaifeng Ge, Jie Tao. Landscape and avifauna changes as an indicator of Yellow River Delta Wetland restoration. Ecological Engineering. 2015; 86 ():162-173.
Chicago/Turabian StyleAng Chen; Xin Sui; Dongsheng Wang; Wengen Liao; Huaifeng Ge; Jie Tao. 2015. "Landscape and avifauna changes as an indicator of Yellow River Delta Wetland restoration." Ecological Engineering 86, no. : 162-173.
Riverine wetlands provide important habitats and travel corridors for resident and transient species, playing a key role in maintaining the diversity of entire landscapes. This paper assessed a long-term (1990–2013) landscape changes and avifauna community dynamics in the Yellow River wetland natural reserves, China. Remote sensing information was combined with field surveys to collect critical data on land use and avifaunal populations. The results reveal that land use has dramatic changes during 1990–2013. Utilized water features have significantly decreased over 20 years, whereas artificial land features such as paddy, dry field and built-up area have shown a steady increasing trend in the three riverine wetlands. The spatial landscape patterns of the three wetlands have become fragmented and notably heterogeneous as results of rapid economic development. With the changes of utilized water features, avifauna data show that some overwintering and transient species are becoming permanent residents. Though there is an abundant and diverse array of bird species utilizing the wetlands, migrating traits of these avifauna species have changed. This study can provide basic information for making effective and sustainable conservation plans for the entire Yellow River wetland natural reserves.
Xin Sui; Liang Chen; Ang Chen; Dongsheng Wang; Wenlin Wang; Huaifeng Ge; Guodong Ji. Assessment of temporal and spatial landscape and avifauna changes in the Yellow River wetland natural reserves in 1990–2013, China. Ecological Engineering 2015, 84, 520 -531.
AMA StyleXin Sui, Liang Chen, Ang Chen, Dongsheng Wang, Wenlin Wang, Huaifeng Ge, Guodong Ji. Assessment of temporal and spatial landscape and avifauna changes in the Yellow River wetland natural reserves in 1990–2013, China. Ecological Engineering. 2015; 84 ():520-531.
Chicago/Turabian StyleXin Sui; Liang Chen; Ang Chen; Dongsheng Wang; Wenlin Wang; Huaifeng Ge; Guodong Ji. 2015. "Assessment of temporal and spatial landscape and avifauna changes in the Yellow River wetland natural reserves in 1990–2013, China." Ecological Engineering 84, no. : 520-531.
This paper mainly summarized the theoretical, methodology and practical development of river ecosystem health assessment. And analyzed the priorities and major issues we are facing. Combined with post-project environmental appraisal (PPEA) which is now increasingly be used. At last recommendations for PPEA in dam and reservoir projects was proposed.
Ang Chen; Xin Sui; Dong Sheng Wang; Wen Gen Liao; Sai Nan Wu; Jie Tao. River Ecosystem Health Assessment and Implications for Post-Project Environmental Appraisal in China. Applied Mechanics and Materials 2014, 692, 8 -12.
AMA StyleAng Chen, Xin Sui, Dong Sheng Wang, Wen Gen Liao, Sai Nan Wu, Jie Tao. River Ecosystem Health Assessment and Implications for Post-Project Environmental Appraisal in China. Applied Mechanics and Materials. 2014; 692 ():8-12.
Chicago/Turabian StyleAng Chen; Xin Sui; Dong Sheng Wang; Wen Gen Liao; Sai Nan Wu; Jie Tao. 2014. "River Ecosystem Health Assessment and Implications for Post-Project Environmental Appraisal in China." Applied Mechanics and Materials 692, no. : 8-12.
This paper mainly reviews the regulations, laws and policies on Post-project Environmental Appraisals of dam projects formulated in the world. In addition, handbooks and guidelines for PPEA were also collected and analyzed from evaluation contents, procedures, methods and latest approaches. International experiences were listed and defragged to compare with China, suggestions were given to complete Chinese EIA and PPEA system.
Ang Chen; Xin Sui; Dong Sheng Wang; Wen Gen Liao; Jie Tao. A Brief Review on Post-Project Environmental Appraisals of Dam Projects and Recommendations for China. Advanced Materials Research 2014, 955-959, 3451 -3456.
AMA StyleAng Chen, Xin Sui, Dong Sheng Wang, Wen Gen Liao, Jie Tao. A Brief Review on Post-Project Environmental Appraisals of Dam Projects and Recommendations for China. Advanced Materials Research. 2014; 955-959 ():3451-3456.
Chicago/Turabian StyleAng Chen; Xin Sui; Dong Sheng Wang; Wen Gen Liao; Jie Tao. 2014. "A Brief Review on Post-Project Environmental Appraisals of Dam Projects and Recommendations for China." Advanced Materials Research 955-959, no. : 3451-3456.