U.S. flag

An official website of the United States government

PubAg

Main content area

You searched for: Subject "rivers" Remove constraint Subject: "rivers"
Start Over

Search

67,874  Search Results

« Previous | 1 - 20 of 67,874 |
Number of results to display per page

Search Results

1. Exploring the impact of new particle formation events on PM2.5 pollution during winter in the Yangtze River Delta, China

Author:
Ou, Jinping; Hu, Qihou; Liu, Haoran; Xu, Shiqi; Wang, Zhuang; Ji, Xiangguang; Wang, Xinqi; Xie, Zhouqing; Kang, Hui
Source:
Journal of environmental sciences (China) 2022 v.111 pp. 75-83
ISSN:
1001-0742
Subject:
river deltas; Yangtze River,   etc   ; air quality; climate; oxidation; ozone; particulates; pollution; relative humidity; winter; China;     Show all 11 Subjects
Abstract:
... New particle formation (NPF) events are an increasingly interesting topic in air quality and climate science. In this study, the particle number size distributions, and the frequency of NPF events over Hefei were investigated from November 2018 to February 2019. The proportions of the nucleation mode, Aitken mode, and accumulation mode were 24.59%, 53.10%, and 22.30%, respectively, which indicates ...
DOI:
10.1016/j.jes.2021.01.005

2. Ambient volatile organic compounds at a receptor site in the Pearl River Delta region: Variations, source apportionment and effects on ozone formation

Author:
Meng, Yao; Song, Junwei; Zeng, Lewei; Zhang, Yingyi; Zhao, Yan; Liu, Xufei; Guo, Hai; Zhong, Liuju; Ou, Yubo; Zhou, Yan; Zhang, Tao; Yue, Dingli; Lai, Senchao
Source:
Journal of environmental sciences (China) 2022 v.111 pp. 104-117
ISSN:
1001-0742
Subject:
river deltas; rivers,   etc   ; air; aromatic compounds; diurnal variation; evaporation; gasoline; models; ozone; pollution; solvents; volatile organic compounds; China;     Show all 13 Subjects
Abstract:
... We present the continuously measurements of volatile organic compounds (VOCs) at a receptor site (Wan Qing Sha, WQS) in the Pearl River Delta (PRD) region from September to November of 2017. The average mixing ratios of total VOCs (TVOCs) was 36.3 ± 27.9 ppbv with the dominant contribution from alkanes (55.5%), followed by aromatics (33.3%). The diurnal variation of TVOCs showed a strong photochem ...
DOI:
10.1016/j.jes.2021.02.024

3. Comprehensive evaluation of the eco-environmental vulnerability in the Yellow River Delta wetland

Author:
Zhang, Hongyang; Sun, Yadong; Zhang, Wenxin; Song, Ziyi; Ding, Zelin; Zhang, Xianqi
Source:
Ecological indicators 2021 v.125 pp. 107514
ISSN:
1470-160X
Subject:
river deltas; Yellow River,   etc   ; mathematical theory; wetlands;     Show all 4 Subjects
Abstract:
... The eco-environmental vulnerability is an important indicator of the development in wetland. However, the vulnerability is influenced by various interacting factors. The interaction among these factors is fuzzy and stochastic, making it difficult to describe the evaluation results accurately and quantitatively. To overcome the difficulty, this study takes the Yellow River Delta wetland as object, ...
DOI:
10.1016/j.ecolind.2021.107514

4. Establishing effective mine closure criteria for river diversion channels

Author:
Flatley, Alissa; Markham, Andy
Source:
Journal of environmental management 2021 v.287 pp. 112287
ISSN:
0301-4797
Subject:
rivers,   etc   ; prediction; stakeholders;     Show all 3 Subjects
Abstract:
... Rivers are frequently relocated into new artificial channels because of mining activity. Current mine closure criteria do not adequately address river diversion practices causing an absence of guidelines and management of river diversion channels post-mining. During mine operation, river diversion channels are designed to convey large floods with an emphasis on channel stability and effective flow ...
DOI:
10.1016/j.jenvman.2021.112287

5. A simple and robust method for identifying the distribution functions of Manning’s roughness coefficient along a natural river

Author:
Attari, Mohammad; Taherian, Mostafa; Hosseini, Seyed Mahmood; Niazmand, Seyed Bahram; Jeiroodi, Mahsa; Mohammadian, Abdolmajid
Source:
Journal of hydrology 2021 v.595 pp. 125680
ISSN:
0022-1694
Subject:
rivers,   etc   ; hydrograph; roughness;     Show all 3 Subjects
Abstract:
... The analysis of unsteady flows in natural rivers is highly complicated. One of the most important factors that causes errors in calculating the flow depth and discharge is the inability to accurately estimate the values of Manning's roughness coefficient (n) for longitudinal river cross-sections. Most conventional methods for calibrating n only provide a mean value for longitudinal river cross-sec ...
DOI:
10.1016/j.jhydrol.2020.125680

6. Distributed-Framework Basin Modeling System: Ⅲ. Hydraulic Modeling System

Author:
Li, Xiaoning; Wang, Chuanhai; Chen, Gang; Fang, Xing; Zhang, Pingnan; Hua, Wenjuan
Source:
Water 2021 v.13 no.5
ISSN:
2073-4441
Subject:
rivers,   etc   ; basins; runoff; China;     Show all 4 Subjects
Abstract:
... A distributed-framework basin modeling system (DFBMS) was developed to simulate the runoff generation and movement on a basin scale. This study is part of a series of papers on DFBMS that focuses on the hydraulic calculation methods in runoff concentration on underlying surfaces and flow movement in river networks and lakes. This paper introduces the distributed-framework river modeling system (DF ...
DOI:
10.3390/w13050649

7. Analysis of Pore Water Pressure and Piping of Hydraulic Well

Author:
Kim, Jinman; Han, Heuisoo; Jin, Yoonhwa
Source:
Water 2021 v.13 no.4
ISSN:
2073-4441
Subject:
rivers,   etc   ; seepage; water;     Show all 3 Subjects
Abstract:
... This paper shows the results of a field appliance study of the hydraulic well method to prevent embankment piping, which is proposed by the Japanese Matsuyama River National Highway Office. The large-scale embankment experiment and seepage analysis were conducted to examine the hydraulic well. The experimental procedure is focused on the pore water pressure. The water levels of the hydraulic well ...
DOI:
10.3390/w13040502

8. Length‐weight and length‐length relationships of three fish species from the Qingshui River in Guizhou province, Southwest China

Author:
Zhu, Xiufang; Mi, Qi
Source:
Journal of applied ichthyology 2021 v.37 no.1 pp. 158-159
ISSN:
0175-8659
Subject:
rivers,   etc   ; ; fish; ichthyology; China;     Show all 5 Subjects
Abstract:
... The present study describes the length‐weight (LWR) and length‐length (LLR) relationships for three indigenous fish species from the Qingshui River, southwestern China. Fishes were collected by electrofishing in May 2015 in the middle Qingshui River. Total length (TL), standard length (SL) and fork length (FL) were measured to the nearest 0.1 cm with a digital calliper and weight (W) was determine ...
DOI:
10.1111/jai.14096

9. New approach to computing mean velocity and discharge

Author:
Abdolvandi, Amir Farbod; Ziaei, Ali Naghi; Moramarco, Tommaso; Singh, Vijay P.
Source:
Hydrological sciences journal 2021 v.66 no.2 pp. 347-353
ISSN:
2150-3435
Subject:
rivers,   etc   ; entropy; hydrograph; models;     Show all 4 Subjects
Abstract:
... Estimation of discharge hydrograph may be needed at river gauging stations where discharge is computed by converting water stage using a stage-discharge relation (a rating curve) or multiplying mean velocity by flow cross-sectional area. The mean velocity is computed by converting the measured maximum velocity to mean velocity using a conversion factor. Estimating the velocity conversion factor at ...
DOI:
10.1080/02626667.2020.1859115

10. Seasonal Changes in Structure and Dynamics in an Urbanized Salt Wedge Estuary

Author:
McKeon, Margaret A.; Horner-Devine, Alexander R.; Giddings, Sarah N.
Source:
Estuaries and coasts 2021 v.44 no.3 pp. 589-607
ISSN:
1559-2723
Subject:
river flow; rivers,   etc   ; asymmetry; estuaries; salinity; seasonal variation; urbanization;     Show all 7 Subjects
Abstract:
... Hydrographic measurements of salt wedge structure and dynamics spanning a 20-fold seasonal range of river discharges are used to investigate the seasonal variability in the strongly stratified Duwamish River Estuary. The effect of river discharge on salt wedge length, stratification, pycnocline thickness, and intratidal differences in salinity structure are evaluated. The salt wedge decreases in l ...
DOI:
10.1007/s12237-020-00788-z

11. The performance of classification and forecasting Dong Nai River water quality for sustainable water resources management using neural network techniques

Author:
Hien Than, Nguyen; Dinh Ly, Che; Van Tat, Pham
Source:
Journal of hydrology 2021 v.596 pp. 126099
ISSN:
0022-1694
Subject:
river water; rivers,   etc   ; neural networks; time series analysis; water quality;     Show all 5 Subjects
Abstract:
... This study has classified and predicted the water quality for the Dong Nai river at different times. The data mining techniques were used to screen out unreliable data. The neural network model FFNN in the form of architecture I(8)-HL(9)-O(1) has been successfully developed to classify the water quality of the Dong Nai river during the period from 2012 to 2019. For this model, the RMSE values for ...
DOI:
10.1016/j.jhydrol.2021.126099

12. Mega-city region sustainability assessment and obstacles identification with GIS–entropy–TOPSIS model: A case in Yangtze River Delta urban agglomeration, China

Author:
Xu, Xueyan; Zhang, Zhonghao; Long, Tao; Sun, Shimeng; Gao, Jun
Source:
Journal of cleaner production 2021 v.294 pp. 126147
ISSN:
0959-6526
Subject:
river deltas; Yangtze River,   etc   ; cities; models; sustainable development; China;     Show all 6 Subjects
Abstract:
... Sustainability is related to support the huge population and improve the residents’ well-being in the Mega-city regions. Sustainability assessment is necessary under the context of implementing the Sustainable Development Goals in 2030. Refer to SDG 11, this study constructed an index system, assessed the sustainability level based on the theory of ‘‘weak’’ and ‘‘strong’’ sustainability and screen ...
DOI:
10.1016/j.jclepro.2021.126147

13. Classification of aquatic macroinvertebrates in flow categories for the adjustment of the LIFE Index to Costa Rican rivers

Author:
Quesada-Alvarado, Francisco; Umaña-Villalobos, Gerardo; Springer, Monika; Picado-Barboza, Jorge
Source:
International journal of ecohydrology & hydrobiology 2021 v.21 no.2 pp. 368-376
ISSN:
1642-3593
Subject:
river flow; rivers,   etc   ; aquatic invertebrates; basins; hydrobiology; Costa Rica;     Show all 6 Subjects
Abstract:
... The LIFE Index can be useful to determine the effect of changes in river flow on the community of aquatic macroinvertebrates and as a tool for the implementation of environmental flows. This study demonstrates how to classify aquatic macroinvertebrates into a flow category in order to adjust the LIFE Index to Costa Rica. A panel of experts was surveyed to classify the most common genera into a wat ...
DOI:
10.1016/j.ecohyd.2020.08.005

14. Identification of close relationship between atmospheric oxidation and ozone formation regimes in a photochemically active region

Author:
Zhao, Kaihui; Luo, Huihong; Yuan, Zibing; Xu, Danni; Du, Yi; Zhang, Shu; Hao, Yuqi; Wu, Yonghua; Huang, Jianping; Wang, Ying; Jiang, Rongsheng
Source:
Journal of environmental sciences (China) 2021 v.102 pp. 373-383
ISSN:
1001-0742
Subject:
river deltas; rivers,   etc   ; oxidation; ozone; photochemistry; pollution; pollution control; China;     Show all 8 Subjects
Abstract:
... Understanding ozone (O₃) formation regime is a prerequisite in formulating an effective O₃ pollution control strategy. Photochemical indicator is a simple and direct method in identifying O₃ formation regimes. Most used indicators are derived from observations, whereas the role of atmospheric oxidation is not in consideration, which is the core driver of O₃ formation. Thus, it may impact accuracy ...
DOI:
10.1016/j.jes.2020.09.038

15. The Dioecious Adenia natalensis W.J.de Wilde (Passifloraceae): Discovery and Description of the Female

Author:
Crouch, Neil R.; Styles, David G.A.
Source:
Haseltonia 2021 v.27 no.1 pp. 77-80
ISSN:
1938-2898
Subject:
river valleys; rivers,   etc   ; Adenia; dioecy; female plants; females; South Africa;     Show all 7 Subjects
Abstract:
... Adenia natalensis W.J.de Wilde, rediscovered recently in the lower Thukela River Valley in central KwaZulu-Natal, South Africa has now been identified from the Mngeni River system to the south, from three additional sites. A single flowering and fruiting female plant has been observed at Botha's Hill near Durban, allowing for a complete description of this dioecious species. ...
DOI:
10.2985/026.027.0109

16. Mean flow velocity in the Nile River, Egypt: an overview of empirical equations and modification for low-flow regimes

Author:
Abdelhaleem, Fahmy S.; Amin, Ahmed M.; Helal, Esam Y.
Source:
Hydrological sciences journal 2021 v.66 no.2 pp. 239-251
ISSN:
2150-3435
Subject:
rivers; Nile River,   etc   ; databases; energy; equations; prediction; water flow; Egypt;     Show all 8 Subjects
Abstract:
... This study presents a formula for estimating the mean flow velocity of the Nile River, Egypt. The proposed formula is presented in the form of the commonly used Manning equation. The derived relationship can be directly incorporated into numerical models and used by hydraulic professionals. The formula is developed using a large database of field measurements from the Nile River and its canals. It ...
DOI:
10.1080/02626667.2020.1853732

17. A Study on Interaction between Overfall Types and Scour at Bridge Piers with a Moving-Bed Experiment

Author:
Lee, Wei-Lin; Lu, Chih-Wei; Huang, Chin-Kun
Source:
Water 2021 v.13 no.2
ISSN:
2073-4441
Subject:
river flow; rivers,   etc   ; bridges (infrastructure); earthquakes; stream channels; water;     Show all 6 Subjects
Abstract:
... River slopes can be changed due to an extreme event, e.g., a large-scale earthquake. This can uplift a riverbed greatly and thereby change the behavior of the river flow into a free or submerged overfall. Corresponding damage, including extreme erosion, on bridge piers located in the river can take place due to the aforementioned flow conditions. A reconstructed bridge pier in the same location wo ...
DOI:
10.3390/w13020152

18. Impacts of Urbanization on Variations of Extreme Precipitation over the Yangtze River Delta

Author:
Kang, Congxuan; Luo, Zujiang; Zong, Wen; Hua, Jian
Source:
Water 2021 v.13 no.2
ISSN:
2073-4441
Subject:
river deltas; Yangtze River,   etc   ; land use; urbanization; water;     Show all 5 Subjects
Abstract:
... The urbanization process is the hallmark of the population’s economic activities and land-use types, including population-, economic-, and landscape-urbanization. The question of how to classify the stations into urbanized and suburbanized stations is important for detecting the contribution rates of urbanization to precipitation extremes. This study used the fuzzy c-means clustering method to cla ...
DOI:
10.3390/w13020150

19. Isomers of emerging per- and polyfluoroalkyl substances in water and sediment from the Cape Fear River, North Carolina, USA

Author:
Saleeby, Brittany; Shimizu, Megumi S.; Sanchez Garcia, Rosa Idalia; Avery, G. Brooks; Kieber, Robert J.; Mead, Ralph N.; Skrabal, Stephen A.
Source:
Chemosphere 2021 v.262 pp. 128359
ISSN:
0045-6535
Subject:
river water; rivers,   etc   ; carbon; pollution; sediments; North Carolina;     Show all 6 Subjects
Abstract:
... Per- and polyfluoroalkyl substances (PFAS) have become ubiquitous environmental contaminants found in many parts of the globe and in all environmental compartments. The phase out of legacy C8 PFAS has led to an increase in functionality of the carbon backbone chain to include ether linkages and branching points. With the increased production of functionalized PFAS, there remains a paucity of infor ...
DOI:
10.1016/j.chemosphere.2020.128359

20. Numerical reconstruction of historical extreme floods: The Guadiana event of 1876

Author:
González-Cao, José; Fernández-Nóvoa, Diego; García-Feal, Orlando; Figueira, Jose R.; Vaquero, José M.; Trigo, Ricardo M.; Gómez-Gesteira, Moncho
Source:
Journal of hydrology 2021 v.599 pp. 126292
ISSN:
0022-1694
Subject:
river flow,   etc   ; basins; watersheds; Europe;     Show all 4 Subjects
Abstract:
... In recent decades, the development of numerical tools has facilitated the ability to reproduce extreme flood events, which allows a far better understanding of their features, contributing to mitigate their negative effects in similar future scenarios. This paper analyzes the flood event that occurred in December 1876 in Badajoz (Spain-Guadiana basin), one of the most catastrophic flood events rec ...
DOI:
10.1016/j.jhydrol.2021.126292