scholarly journals Assessment of medium and small river health based on macroinvertebrates habitat suitability curves: a case study in a tributary of Yangtze River, China

Water Policy ◽  
2020 ◽  
Vol 22 (4) ◽  
pp. 602-621
Author(s):  
Yifan Su ◽  
Weiming Li ◽  
Liu Liu ◽  
Jinjing Li ◽  
Xuyang Sun ◽  
...  
Keyword(s):  
Health Status ◽  
Habitat Suitability ◽  
Yangtze River ◽  
Evaluation Method ◽  
Pearson Correlation ◽  
Small River ◽  
Low Flow ◽  
Small Rivers ◽  
Physical Parameters ◽  
River Health

Abstract The health of medium and small river ecosystems is threatened by increasing hydropower development and human activities. How to properly diagnose rivers has become a global concern. As a well-accepted theory, the aquatic organism density can be an indicator of river health. A new river health assessment method based on macroinvertebrates habitat suitability curves (M-HSC) was proposed. In this study, the health of Qiaobian River (QBR), a tributary of Yangtze River, China was evaluated by investigating the distribution of macroinvertebrates, chemical and physical parameters during winter 2018 (low flow season) and summer 2019 (high flow season). Based on habitat suitability of dominant macroinvertebrates, the key habitat factors were screened by canonical correspondence analysis (CCA) and Pearson correlation analysis. Suitability curves were determined by Generalized Additive Model (GAM). Ecosystem health comprehensive index method was used to evaluate the health status. The results show most suitable conditions for Corbicula fluminea containing chemical oxygen demand (CODMn) of 1.48 mg L−1, total nitrogen (TN) of 0.27 mg L−1, dissolved oxygen (DO) of 11.17 mg L−1, pH of 8.42, turbidity of 1.76 NTU, and water depth (Dep) of 0.35 m. The health status of QBR is spatially heterogeneous with the apparently better upstream than the downstream. In general, 25, 12.5, 12.5% of the samples were classified as nature, health and sub-health status, respectively and the rest 50% were lower than sub-health. The results are consistent with the environmental quality standards for surface water in China (GB3838-2002), suggesting the applicability of macroinvertebrates habitat suitability for evaluating river health. By minimizing the temporal and spatial limitations of comprehensive evaluation method and indicator species method, this study, for the first time, used macroinvertebrates habitat suitability curves to assess the health of medium and small rivers. The study will provide new insights for future river health assessments.

Health status evaluation method of CNC machine tools based on grey clustering analysis and fuzzy comprehensive evaluation

2021 ◽  
pp. 1-18
Author(s):  
Xiaoqing Huang ◽  
Zhilong Wang ◽  
Shihao Liu
Keyword(s):  
Health Status ◽  
Clustering Analysis ◽  
Machine Tools ◽  
Evaluation Method ◽  
Comprehensive Evaluation ◽  
Fuzzy Comprehensive Evaluation ◽  
Indicator System ◽  
Cnc Machine Tools ◽  
Cnc Machine ◽  
Grey Clustering

In order to solve the problem of health evaluation of CNC machine tools, an evaluation method based on grey clustering analysis and fuzzy comprehensive evaluation was proposed. The health status grade of in-service CNC machine tools was divided, and the performance indicator system of CNC machine tools was constructed. On the above basis, the relative importance of each performance and its indicators were combined, and grey clustering analysis and fuzzy comprehensive evaluation was utilized to evaluate the health status of in-service CNC machine tools to determine their health grade. The proposed health status evaluation method was applied to evaluate the health level of an in-service gantry CNC machine that can be used for the machining propellers, and the results shown that the health status of the whole gantry CNC machine tool is healthy. The proposed evaluation method provides useful references for further in-depth research on the health status analysis and optimization of CNC machine tools.

Exploring the water–energy–food nexus from a perspective of agricultural production efficiency using a three-stage data envelopment analysis modelling evaluation method: a case study of the middle and lower reaches of the Yangtze River, China

Water Policy ◽  
2018 ◽  
Vol 21 (1) ◽  
pp. 49-72 ◽  
Author(s):  
Jiazhong Zheng ◽  
Weiguang Wang ◽  
Dan Chen ◽  
Xinchun Cao ◽  
Wanqiu Xing ◽  
...  
Keyword(s):  
Data Envelopment Analysis ◽  
Agricultural Production ◽  
Yangtze River ◽  
Production Efficiency ◽  
Evaluation Method ◽  
Data Envelopment ◽  
The Yangtze River ◽  
Agricultural Resources ◽  
Important Challenge

Abstract A coordinated nexus of agricultural resources is vital to achieve food security and sustainable development in China. Comprehensively considering the water–energy–food nexus as well as the external environment, this study adopts a three-stage data envelopment analysis (DEA) modelling evaluation method to assess the agricultural production efficiency (APE) of seven provinces in the middle and lower reaches of the Yangtze River (MLYR) during 1996–2015. The results show that the three-stage DEA modelling evaluation method reveals real APE and is considered to be a better quantitative method than conventional approaches. A gradually widening range of APE is an important challenge for this region. Significantly, this region generates huge demands for agricultural resources. Moreover, regional emissions of greenhouse gases (GHG) decreased from 34.20 million tons standard coal in 1996 to 32.11 million tons standard coal in 2015, though APE has continued to decrease by 2.56% in the past two decades. In general, the management and technology levels should be improved simultaneously, even though specific opportunities for APE improvement vary across provinces in MLYR. However, understanding the temporal and spatial variation of APE along with the WEF nexus from a production-based insight is a vital step toward appropriately targeted policy making for nationwide resources savings and emissions reduction.

scholarly journals The inventory of vegetation cover of small river valleys in the north-east of the Samara Region

2021 ◽  
Vol 10 (1) ◽  
pp. 157-162
Author(s):  
Vera Valentinovna Solovieva
Keyword(s):  
Plant Species ◽  
Vegetation Cover ◽  
Higher Plants ◽  
Small River ◽  
Wild Plants ◽  
Small Rivers ◽  
North East ◽  
The North ◽  
The Right ◽  
River Valleys

The study covered 10 small rivers in the North-Eastern part of the Samara Volga region. The author studied the vegetation cover, which is understood as a set of phytocoenoses and their constituent plant species. On the territory of Pokhvistnevsky District, there are two groups of river valleys that are heterogeneous in geobotanical terms. The first group includes the rivers with forested valleys (Kutlugush, Murakla, Karmalka). Their slopes are more or less symmetrical and steep. The vegetation cover of an undeveloped floodplain is usually uniform, and there is usually no belt. The valleys of the second group are treeless; their slopes are sharply asymmetrical (Amanak, Tergala, Talkish). The right-bank tributary of the Maly Kinel River the Lozovka River with its length of 20 km and the left tributary Kuvayka River with its length of 16 km were studied on the territory of Kinel-Cherkassky District. The Padovka and Zaprudka rivers and the right tributaries of the Bolshoi Kinel River (Kinelsky District) were also studied. The most common associations are (Salix fragilis heteroherbosa, Scirpus sylvaticus purum, Agrostis stolonifera Amoria repens, Elytrigia repens + Poa angustifolia heteroherbosa). In total, 19 types of phytocoenoses were noted, 4 of them are found in half of the studied rivers. In the plant communities of small river valleys there are 232 species of higher wild plants, which belong to 139 genera from 48 families. This is 60% of the total number of higher plants registered in the flora of small river valleys of the Samara Region. Rare protected plant species are registered here: Adonis volgensis Steven ex DC., Cacalia hastata L., Delphinium cuneatum Stev. ex DC., Globularia punctata Lapeyr.

scholarly journals Chironomidae (Order: Diptera) diversity in relation to water quality of highland rivers at Cameron Highlands, Malaysia

2021 ◽  
Vol 42 (3(SI)) ◽  
pp. 824-831
Author(s):  
A.K. Ahmad ◽  
◽  
A. Hafizah ◽  
S.O. Sharifah Aisyah ◽  
◽  
...  
Keyword(s):  
Water Quality ◽  
Water Quality Index ◽  
Quality Index ◽  
Pearson Correlation ◽  
Diversity Indices ◽  
Class I ◽  
Small Rivers ◽  
Tropical Region ◽  
Wide Range ◽  
Cameron Highlands

Aim: This study aims to determine Chironomidae diversity and distribution in three small rivers at Cameron Highlands in relation to their response to water quality conditions. Methodology: Fifteen sites from three rivers (Palas River, Pauh River and Bertam River) were chosen for water quality measurements and Chironomidae sampling. Water quality was analysed following APHA standard methods and chironomid was identified to genus level. The rivers were classified based on Malaysian’s Water Quality Index (WQI) and macroinvertebrates diversity and distribution was analysed using diversity indices. Comparison between sites and river was undertaken using one-way ANOVA and chironomid appearance in relation to water quality was evaluated using Pearson correlation test. Results: Chironomidae (Order: Diptera) distribution at high altitude rivers in Malaysia is not well documented although this group of insect has a wide range of distribution in tropical region. Based on Malaysian water quality index (WQI), result shows all rivers were in Class I. Although still in Class I, Bertam River has slight lower water quality due to higher ammoniacal nitrogen and total suspended solids. The diversity indices also demonstrate that Bertam Rivers was in stress conditions, and other two were in moderate conditions. Three subfamilies (Chironominae, Orthocladiinae and Tanypodinae) were recorded, which comprises of 1963 individuals. Tvetenia (Subfamily: Orthocladiinae) was the most dominant but only dominated Palas River and Pauh River. Another genus from Orthocladiinae (Crocotopus and Rheocrocotopus) also recorded dominant only in Palas River and Pauh River, but lesser in Bertam River. Only Polypedilum (Subfamily: Chironominae) which was second highest recorded, dominated in all rivers, even highest in Bertam River. Amongst dominant genus, only Polypedilum was found dominant in all rivers, others were only dominating Palas River and Pauh River only. Interpretation: This findings exhibit wide range of adaptations and potential use of Polypedilum as biological indicator. Due to availability of incomplete keys, identification to species level cannot be undertaken. However, this study reveals thirteen different sub-group of Polypedilum based mouthpart organs, which represent different species for tropical ecosystems.

scholarly journals A 439-year simulated daily discharge dataset (1861–2299) for the upper Yangtze River, China

2020 ◽  
Vol 12 (1) ◽  
pp. 387-402
Author(s):  
Chao Gao ◽  
Buda Su ◽  
Valentina Krysanova ◽  
Qianyu Zha ◽  
Cai Chen ◽  
...  
Keyword(s):  
Climate Change ◽  
Yangtze River ◽  
Weighted Least Squares ◽  
Low Flow ◽  
Historical Period ◽  
Hydrological Models ◽  
Upper Yangtze River ◽  
Daily Discharge ◽  
The Upper Yangtze River ◽  
Soil And Water

Abstract. The outputs of four global climate models (GFDL-ESM2M, HadGEM2-ES, IPSL-CM5A-LR and MIROC5), which were statistically downscaled and bias corrected, were used to drive four hydrological models (Hydrologiska Byråns, HBV; Soil and Water Assessment Tool, SWAT; Soil and Water Integrated Model, SWIM; and Variable Infiltration Capacity, VIC) to simulate the daily discharge at the Cuntan hydrological station in the upper Yangtze River from 1861 to 2299. As the performances of hydrological models in various climate conditions could be different, the models were first calibrated in the period from 1979 to 1990. Then, the models were validated in the comparatively wet period, 1967–1978, and in the comparatively dry period, 1991–2002. A multi-objective automatic calibration programme using a univariate search technique was applied to find the optimal parameter set for each of the four hydrological models. The Nash–Sutcliffe efficiency (NSE) of daily discharge and the weighted least-squares function (WLS) of extreme discharge events, represented by high flow (Q10) and low flow (Q90), were included in the objective functions of the parameterization process. In addition, the simulated evapotranspiration results were compared with the GLEAM evapotranspiration data for the upper Yangtze River basin. For evaluating the performances of the hydrological models, the NSE, modified Kling–Gupta efficiency (KGE), ratio of the root-mean-square error to the standard deviation of the measured data (RSR) and Pearson's correlation coefficient (r) were used. The four hydrological models reach satisfactory simulation results in both the calibration and validation periods. In this study, the daily discharge is simulated for the upper Yangtze River under the preindustrial control (piControl) scenario without anthropogenic climate change from 1861 to 2299 and for the historical period 1861–2005 and for 2006 to 2299 under the RCP2.6, RCP4.5, RCP6.0 and RCP8.5 scenarios. The long-term daily discharge dataset can be used in the international context and water management, e.g. in the framework of Inter-Sectoral Impact Model Intercomparison Project (ISIMIP) by providing clues to what extent human-induced climate change could impact streamflow and streamflow trend in the future. The datasets are available at: https://doi.org/10.4121/uuid:8658b22a-8f98-4043-9f8f-d77684d58cbc (Gao et al., 2019).

scholarly journals Hydrodynamic Resistance of Intracranial Flow-Diverter Stents: Measurement Description and Data Evaluation

2019 ◽  
Vol 11 (1) ◽  
pp. 1-13 ◽  
Author(s):  
Benjamin Csippa ◽  
Dániel Gyürki ◽  
Gábor Závodszky ◽  
István Szikora ◽  
György Paál
Keyword(s):  
Flow Rate ◽  
Evaluation Method ◽  
Small Sample Size ◽  
Flow Diverter ◽  
Small Sample ◽  
Low Flow ◽  
Hydrodynamic Resistance ◽  
Metallic Surface ◽  
Stent Deployment ◽  
Geometrical Properties

Abstract Purpose Intracranial aneurysms are malformations forming bulges on the walls of brain arteries. A flow diverter device is a fine braided wire structure used for the endovascular treatment of brain aneurysms. This work presents a rig and a protocol for the measurement of the hydrodynamic resistance of flow diverter stents. Hydrodynamic resistance is interpreted here as the pressure loss versus volumetric flow rate function through the mesh structure. The difficulty of the measurement is the very low flow rate range and the extreme sensitivity to contamination and disturbances. Methods Rigorous attention was paid to reproducibility, hence a strict protocol was designed to ensure controlled circumstances and accuracy. Somewhat unusually, the history of the development of the rig, including the pitfalls was included in the paper. In addition to the hydrodynamic resistance measurements, the geometrical properties—metallic surface area, pore density, deployed and unconstrained length and diameter—of the stent deployment were measured. Results Based on our evaluation method a confidence band can be determined for a given deployment scenario. Collectively analysing the hydrodynamic resistance and the geometric indices, a deeper understanding of an implantation can be obtained. Our results suggest that to correctly interpret the hydrodynamic resistance of a scenario, the deployment length has to be considered. To demonstrate the applicability of the measurement, as a pilot study the results of four intracranial flow diverter stents of two types and sizes have been reported in this work. The results of these measurements even on this small sample size provide valuable information on differences between stent types and deployment scenarios.

scholarly journals A method for low-flow estimation at ungauged sites: a case study in Wallonia (Belgium)

2013 ◽  
Vol 17 (4) ◽  
pp. 1319-1330 ◽  
Author(s):  
M. Grandry ◽  
S. Gailliez ◽  
C. Sohier ◽  
A. Verstraete ◽  
A. Degré
Keyword(s):  
Return Period ◽  
Management Practice ◽  
Global Model ◽  
Low Flow ◽  
Quality Analysis ◽  
Flow Index ◽  
Physical Parameters ◽  
Integrated Water Management ◽  
Explanatory Variables ◽  
Ungauged Sites

Abstract. Well-integrated water management can notably require estimating low flows at any point of a river. Depending on the management practice, it can be needed for various return periods. This is seldom addressed in the literature. This paper shows the development of a full analysis chain including quality analysis of gauging stations, low-flow frequency analysis, and building of a global model to assess low-flow indices on the basis of catchment physical parameters. The most common distributions that fit low-flow data in Wallonia were two-parameter lognormal and gamma. The recession coefficient and percolation were the most explanatory variables, regardless of the return period. The determination coefficients of the models ranged from 0.51 to 0.67 for calibration and from 0.61 to 0.80 for validation. The regression coefficients were found to be linked to the return period. This was used to design a complete equation that gives the low-flow index based on physical parameters and the desired return period (in a 5 to 50 yr range). The interest of regionalisation and the development of regional models are also discussed. Four homogeneous regions are identified, but to date the global model remains more robust due to the limited number of 20-yr-long gauging stations. This should be reconsidered in the future when enough data will be available.

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