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Comparative evaluation of impacts of climate change and droughts on river flow vulnerability in Iran

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Water Science and Engineering 2020年第4期13卷 265-274页

作者： Zahra Noorisameleh Shahriar Khaledi Alireza Shakiba Parviz Zeaiean Firouzabadi William AGough MMonirul Qader Mirza Faculty of Earth Sciences Shahid Beheshti UniversityTehran ***Iran Department of Physical and Environmental Sciences University of Toronto ScarboroughToronto M1C 1A4Canada Faculty of Geographical Sciences Kharazmi UniversityTehran 15719-14911Iran

rivers in arid and semi-arid regions are threatened by droughts and climate *** study focused on a comparative evaluation of the impacts of climate change and droughts on the vulnerability of river flows in three basins with diverse climates in *** standardized precipitation-evapotranspiration index(SPEI)and precipitation effectiveness variables(PEVs)extracted from the conjunctive precipitation effectiveness index(CPEI)were used to analyze the drought *** investigate hydrological droughts in the basins,the normalized difference water index(NDWI)and the streamflow drought index(SDI)were calculated and *** effects of droughts were assessed under various representative concentration pathway(RCP)*** in the number of wet days and precipitation depth restricted hydrological droughts,whereas an increasing number of dry days amplified their *** projected increases in dry days and precipitation over short durations throughout a year under future climate scenarios would produce changes in drought and flood periods and ultimately impact the frequency and severity of hydrological *** RCP 4.5,an increase in the frequencies of moderate and severe meteorological/hydrological droughts would further affect the Central Desert *** RCPs 2.6 and 8.5,the frequencies of severe and extreme droughts would increase,but the drought area would be smaller than that under RCP 4.5,demonstrating less severe drought *** to the shallow depths of most rivers,SDI was found to be more feasible than NDWI in detecting hydrological droughts.©2020 Hohai *** and hosting by Elsevier *** is an open access article under the CC BY-NC-ND license(http://***/licenses/by-nc-nd/4.0/).

关键词： Climate change river flow Precipitation Drought index Standardized precipitation-evapotranspiration index Iran

COUPLING EFFECT OF SEEPAGE flow AND river flow ON THE BANK FAILURE

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Journal of Hydrodynamics 2011年第6期23卷 834-840页

作者： NING Bo WU- Shi-qiang TAN Ye-fei XIE Xing-hua YAN Jun YAN Zhong-min GENG Yan-qiong College of Water Conservancy and Hydropower Engineering Hohai University Nanjing 210098 China Nanjing Hydraulic Research Institute Nanjing 2100-29 China Nanjing Hydraulic Research Institute.Nanjing 210029 China Lian Yungang Technical College Lian Yungang 222000 China

On the basis of the generalized physical model of the riverbank, the experiments were conducted to study the mechanisms of riverbank failure under the coupling effect of seepage flow and river flow. The experimental setup was specially designed, as well as test point location, parameters and procedures, and the main influencing factors were analyzed affecting riverbank failure based on the failure types, the variations of pore water pressure and soil displacement. The results indicated that the coupling effect has different influences on the bank failure in three aspects： the failure type, the process and the extent. In addition, the river flow played a more important role than the seepage flow in the coupling effect on the bank failure.

关键词： bank failure seepage flow river flow physical model test

Analysis of long-term dependence phenomenon in Benue river flow process and its hypothesis testing

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Chinese Journal of Oceanology and Limnology 2008年第3期26卷 313-322页

作者： Martins Y. OTACHE 李致家 Mohammad BAKIR State Key Laboratory of Hydrology-Water Resources ＆ Hydraulic Engineering Hohai University Nanjing 210098 China

In this paper, the long-term dependence phenomenon （the Hurst Effect） which characterizes hydrological and other geophysical times series is studied. The long-term memory is analysed for both daily and monthly streamflow series of the Benue river at Makurdi, Nigeria by using heuristic methods and testing specifically the null hypothesis of short-term memory in the monthly flow series. Results obtained by applying heuristic procedures indicated that there may be the presence of long-term memory component in mean daily flow series but there is no discernible reason to suspect the presence in both average monthly and maximum monthly flow series （extreme event）. Hypothesis testing was conducted by using original and modified versions of rescaled range statistic. When the modified rescaled range, which accounts for short-term memory in the series, is used, the null hypothesis is accepted for both the average monthly and maximum monthly flow series, indicating little or no probable presence of long-term memory in the series. An identical conclusion is also arrived at when second null hypothesis for independence of the monthly flow series is tested. Therefore, apart from the mean daily flow series, there is little evidence of long-term dependence in the Benue river streamflow series at Makurdi. However, considering the limited length of data used, the results are inconclusive.

关键词： Hurst exponent hydrological method time series river flow long memory Nigeria

Climatic variations of general atmospheric circulation,precipitation and river flow of the territory of Kazakhstan

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Research in Cold and Arid Regions 2013年第1期5卷 109-113页

作者： Vitaly Salnikov Galina Turulina Svetlana Polyakova Marat Moldahmetov Lyazzat Mahmudova Department of Meteorology and Hydrology Faculty of Geography and Environmental Sciences al-Faraby Kazakh National Uni- versity Almaty Kazakhstan

Methods of calculating the basic hydrological characteristics of a water resource assessment, as well as the planning and manage- ment of their long-term use are based upon the concept of stationarity of long-term flow fluctuations. However, data of researches by hydrologists and climatologists clearly indicate that there are long-period changes in the characteristics of precipitation and riv- er flow. This article discusses the variations of annual precipitation and fiver flow in the Ishim river Basin in Kazakhstan, based on the W, C and E classification developed by GY. Vangengeim who analyzed the long-term variability of anomalies by the num- ber of days with some form of atmospheric circulation. From this study, the largest anomaly of the macro-circulation processes was revealed, and a comparative analysis of the number of days with various forms of atmospheric circulation and precipitation anomalies was made. It was demonstrated that the nature of atmospheric circulation depends on the distribution of precipitation; however, precipitation is also highly dependent on local physiographic conditions. The analysis of anomalous precipitation during the maximum number of days of positive anomalies with various forms of atmospheric circulation was also carried out. This study presents some results t^om the preliminary analysis of annual river flow linked with forms of atmospheric circulation.

关键词： circulation indices circulation forms alrnospheric precipitation river flow annual drain circulation eras

VARIATION IN flow AND SEDIMENT OF DASHA river AND INFLUENCE OF HUMAN ACTIVITIES ON IT IN SOUTHWEST REGION OF ANHUI PROVINCE

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Chinese Geographical Science 2006年第2期16卷 109-115页

作者： CHEN Bao-ping ZHANG Jian-chun State Key Laboratory of Estuarine and Coastal Research East China Normal Un＆ersity Shanghai 200062 P. R. China Department of Geography Chizhou Teachers College of A nhui Province Chizhou 247000 P. R. China School of Humanities Hangzhou Teachers College Hangzhou 310036 P. R. China

Soil and water loss is now a major environmental problem in many areas of China, especially in the area of the Dabie Mountain, Anhui Province, which results in environmental degradation and does harm to the people＇s life and production there. Based on the observational records from the Dasha river, the authors analyze the character of the variation in flow and sediment in different flood and dry seasons from 1970 to 2000. The result shows that human activities had significantly reduced the sediment discharge and sediment module, and increased the runoff in low-water seasons since the 1980s. The average contribution rate ofhnman activities to decreasing sediment was 65.67%, and at the same period the contribution rate of runoff and rainfall was about 34.33%. Therefore, it is necessary to take the biological and engineering measures to solve the problem of soil and water loss in the Dasha river watershed.

关键词： river flow sediment discharge human activities effect Dasha river southwest of Anhui Province

Assessment of Climate Change’s Impacts on river flows in the Songwe Sub-Basin

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Open Journal of Modern Hydrology 2023年第2期13卷 141-164页

作者： Lupakisyo G. Mwalwiba Gislar E. Kifanyi Edmund Mutayoba Julius M. Ndambuki Nyemo Chilagane College of Engineering and Technology Mbeya University of Science and Technology Mbeya Tanzania Department of Irrigation and Water Supply Engineering Water Institute Dar es Salaam Tanzania Tshwane University of Technology Pretoria South Africa Tanzania Research and Conservation Organization Morogoro Tanzania

river flow in the Songwe sub-basin is predicted to alter due to climate change, which would have an impact on aquatic habitats, infrastructure, and people’s way of life. Therefore, the influence of climate change should be taken into account when making decisions about the sustainable management of water resources in the sub-basin. This study looked into how river discharge would react to climate change in the future. By contrasting hydrological characteristics simulated under historical climate (1981-2010) with projected climate (2011-2040, 2041-2070, and 2071-2100) under two emission scenarios, the effects of climate change on river flow were evaluated (RCP 4.5 and RCP 8.5). The ensemble average of four CORDEX regional climate models was built to address the issue of uncertainty introduced by the climate models. The SWAT model was force-calibrated using the results from the generated ensemble average for the RCP 4.5 and RCP 8.5 emission scenarios in order to mimic the river flow during past (1981-2010) and future (2011-2100) events. The increase in river flows for the Songwe sub-basin is predicted to be largest during the rainy season by both the RCP 4.5 and RCP 8.5 scenarios. Under RCP 8.5, the abrupt decrease in river flow is anticipated to reach its maximum in March 2037, when the discharge will be 44.84 m3/sec, and in March 2027, when the discharge will be 48 m3/sec. The extreme surge in river flow will peak, according to the RCA4, in February 2023, in April 2083 under RCP 4.5, and, according to the CCLM4 and RCA4, in November 2027 and November 2046, respectively. The expected decrease and increase in river flow throughout both the dry and wet seasons may have an impact on the management of the sub-water basin’s resources, biodiversity, and hydraulic structures. The right adaptations and mitigation strategies should be adopted in order to lessen the negative consequences of climate change on precipitation, temperature, and river flow in t

关键词： Climate Change Climate Models Songwe river Sub-Basin river flow SWAT

Real-Time and Intelligent Flood Forecasting Using UAV-Assisted Wireless Sensor Network

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Computers, Materials & Continua 2022年第1期70卷 715-738页

作者： Shidrokh Goudarzi Seyed Ahmad Soleymani Mohammad Hossein Anisi Domenico Ciuonzo Nazri Kama Salwani Abdullah Mohammad Abdollahi Azgomi Zenon Chaczko Azri Azmi Centre for Artificial Intelligent(CAIT) Universiti Kebangsaan MalaysiaBangi43600Malaysia School of Computer Engineering Iran University of Science and TechnologyResalat Sq.16846-13114TehranIran School of Computing Faculty of Engineering Universiti Teknologi MalaysiaJohorMalaysia School of Computer Science and Electronic Engineering University of EssexColchester CO43SQUnited Kingdom Department of Electrical Engineering and Information Technologies University of Naples“Federico II”Naples80125Italy Razak Faculty of Technology and Informatics Universiti Teknologi MalaysiaKuala Lumpur54100Malaysia School of Electrical and Data Engineering University of Technology SydneyUltimoNSWAustralia

The Wireless Sensor Network(WSN)is a promising technology that could be used to monitor rivers’water levels for early warning flood detection in the 5G ***,during a flood,sensor nodes may be washed up or become faulty,which seriously affects network *** address this issue,Unmanned Aerial Vehicles(UAVs)could be integrated with WSN as routers or data mules to provide reliable data collection and flood *** light of this,we propose a fault-tolerant multi-level framework comprised of a WSN and a UAV to monitor river *** framework is capable to provide seamless data collection by handling the disconnections caused by the failed nodes during a ***,an algorithm hybridized with Group Method Data Handling(GMDH)and Particle Swarm Optimization(PSO)is proposed to predict forthcoming floods in an intelligent collaborative *** proposed water-level prediction model is trained based on the real dataset obtained fromthe Selangor river *** performance of the work in comparison with other models has been also evaluated and numerical results based on different metrics such as coefficient of determination(R2),correlation coefficient(R),RootMean Square Error(RMSE),Mean Absolute Percentage Error(MAPE),and BIAS are provided.

关键词： Unmanned aerial vehicles wireless sensor networks group method data handling particle swarm optimization river flow prediction

THREE DIMENSIONAL NUMERICAL MODELLING OF flow AND SEDIMENT TRANSPORT IN riverS

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International Journal of Sediment Research 2007年第3期22卷 188-198页

作者： M. A. MEKONNEN B. DARGAHI Research candidate KTH Land & Water Resource Engrg. Division of Hydraulic Engrg Stockholm Associate Professor KTH Land & Water Resource Engrg. Division of Hydraulic Engrg. Stockholm

The 3D numerical model, ECOMSED (open source code), was used to simulate flow and sediment transport in rivers. The model has a long history of successful applications to oceanic, coastal and estuarine waters. Improvements in the advection scheme, treatment of river roughness parameterization and shear stress partitioning were necessary to reproduce realistic and comparable results in a river application. To account for the dynamics of the mobile bed boundary, a model for the bed load transport was included in the code. The model reproduced observed secondary currents, bed shear stress distribution and erosion-deposition patterns on a curved channel. The model also successfully predicted the general flow patterns and sediment transport characteristics of a 1-km long reach of the river Klar?lven, located in the north of the county of V?rmland, Sweden.

关键词： Roughness parameterization Numerical models river flow Sediment transport

SEDIMENT TRANSPORT CAPACITY-AN IMPROVED BAGNOLD FORMULA

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International Journal of Sediment Research 2007年第1期22卷 27-38页

作者： Sung-Cheol KOH In-Soo KIM Young-Chae SONG

This paper re-examines Bagnold’s theorem of sediment transport. Different from the stream power defined by Bagnold, i.e., τoV, this study shows that the total load of sediment-laden flow, gt, is related to near bed energy dissipation rate, i.e., τou*’. An attempt is made to explain the empirical relation. The ratio (=k) of measured total load, gt, to the product of near bed velocity, u*’, and energy dissipation rate, τou*’, is analyzed. It is found that k is independent of the Rouse number, Z, if Z is greater than 2.6, but the coefficient k decreases with the increase of Z when Z rivers and canals confirms that the proposed formula can be used to compute the total load with accuracy.

关键词： Sediment transport river flow Total sediment discharge Stream power