scholarly journals Riverbank erosion: factors, mechanism, human activity

2019 ◽  
pp. 3-17
Author(s):  
K. M. Berkovich ◽  
L. V. Zlotina ◽  
L. A. Turykin
Keyword(s):  
Human Activity ◽  
Sediment Load ◽  
Erosion Resistance ◽  
Hydrological Regime ◽  
Annual Runoff ◽  
River Channel ◽  
Volga River ◽  
Riverbank Erosion ◽  
Bank Protection ◽  
Main Factors

The riverbank erosion produces a great risk for the urban development, structures and communications located on the banks. Bank erosion, as an integral part of the lateral river channel migrations, is a multi-factorial phenomenon. Empirical evidence suggests that the riverbank erosion depends on the size of the river, the morphology of the bends, water flow; however, a big role plays erosion resistance of the banks, due to their structure and vegetation. It varies at changeable riverbank soils wetting in accordance with the hydrological regime of the river. Human activity contributes significantly to the intensification of lateral migrations, especially the construction of reservoirs that change the hydrological regime of rivers and sediment transport. Incision, daily flow regulation, redistribution of annual runoff, reducing the sediment load are the main factors that intensify the riverbank erosion. As an example, the situated downstream of the dam sections of the Volga River and Sheksna River in the Rybinsk City were examined and all these factors were revealed there themselves clearly. Considering these factors allowed predicting the riverbank erosion and provided the basis for bank protection program.

Quantifying the uncertainty in riverbank erosion for risk-informed river engineering

2020 ◽  
Author(s):  
Eddy Langendoen ◽  
Mick Ursic
Keyword(s):  
Probability Density ◽  
Erosion Resistance ◽  
Bank Erosion ◽  
Probability Density Functions ◽  
Density Functions ◽  
River Engineering ◽  
Protection Measures ◽  
Riverbank Erosion ◽  
Bank Protection ◽  
Material Erosion

<p>Riverbank erosion is a ubiquitous, natural process. Typically, it occurs during larger flood events when the applied forces exerted by the flowing water on a bank exceed some erosion-resistance threshold. Riverbank protection may be needed when critical infrastructure is present or planned near eroding banks, which requires the quantification of the risk of infrastructure failure by bank erosion. Similarly, renaturalization of many European streams, for example through removal of bank protection measures, necessitates the quantification of expected river width adjustment. Unfortunately, we have been unable to accurately quantify bank erosion rates to date. Limitations exist in characterizing both the applied and resisting forces. For example, bank roughness co-evolves with erosion, which makes it difficult to adequately resolve the forces acting on the bank material. Bank material erosion-resistance of fine-grained soils varies significantly, that is over orders of magnitude, both spatially and temporally. Moreover, existing techniques to measure bank material erosion-resistance do not always produce repeatable results. As a consequence, existing bank erosion models, such as the widely used Bank Stability and Toe Erosion Model (BSTEM), require extensive calibration and validation. This is often unsatisfactory to river engineering professionals that have to make decisions on where to place bank protection measures and the level of protection required. The decision-making process could benefit from a risk-based analysis that quantifies the uncertainty in calculated bank retreat rate. Recent enhancements to the BSTEM model allow users to input probability density functions of (measured) bank roughness and bank material erosion-resistance properties. A Monte Carlo analysis then quantifies the effects of both variability and uncertainty in these parameters on bank retreat. We will present how the shape of different probability density functions affect the probability density function of bank retreat. Results will be further presented of application of the new model to assist in prioritizing riverbank restoration measures along the Lower American and Sacramento Rivers, CA, USA, to prevent failure of levees that protect the City of Sacramento from flooding.</p>

scholarly journals Longer Growing Seasons Cause Hydrological Regime Shifts in Central European Forests

Forests ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1656
Author(s):  
Petr Kupec ◽  
Jan Deutscher ◽  
Martyn Futter
Keyword(s):  
Regime Shift ◽  
Hydrological Regime ◽  
Annual Runoff ◽  
Order Effects ◽  
Runoff Generation ◽  
Central European ◽  
European Forests ◽  
Water Limitation ◽  
Growing Seasons

In this study, we present evidence for a hydrological regime shift in upland central European forests. Using a combination of long-term data, detailed field measurements and modelling, we show that there is a prolonged and persistent decline in annual runoff: precipitation ratios that is most likely linked to longer growing seasons. We performed a long term (1950–2018) water balance simulation for a Czech upland forest headwater catchment calibrated against measured streamflow and transpiration from deciduous and coniferous stands. Simulations were corroborated by long-term (1965–2018) borehole measurements and historical drought reports. A regime shift from positive to negative catchment water balances likely occurred in the early part of this century. Since 2007, annual runoff: precipitation ratios have been below the long-term average. Annual average temperatures have increased, but there have been no notable long term trends in precipitation. Since 1980, there has been a pronounced April warming, likely leading to earlier leaf out and higher annual transpiration, making water unavailable for runoff generation and/or soil moisture recharge. Our results suggest a regime shift due to second order effects of climate change where increased transpiration associated with a longer growing season leads to a shift from light to water limitation in central European forests. This will require new approaches to managing forests where water limitation has previously not been a problem.

scholarly journals Case Study: Influence of Three Gorges Reservoir Impoundment on Hydrological Regime of the Acipenser sinensis Spawning Ground, Yangtze River, China

2021 ◽  
Vol 9 ◽  
Author(s):  
Yinjun Zhou ◽  
Zhijing Li ◽  
Shiming Yao ◽  
Miner Shan ◽  
Chao Guo
Keyword(s):  
Sediment Load ◽  
Hydrological Regime ◽  
Three Gorges ◽  
Spawning Ground ◽  
Chinese Sturgeon ◽  
The Three Gorges ◽  
Reservoir Impoundment ◽  
River Cross Section

After the construction of the Three Gorges Dam (TGD) in China, the downstream has been affected by the reduction in sediment discharge and regulation of flow processes, which have resulted in severe scouring and changes hydrological regime. Consequently, the spawning ground of Chinese sturgeon distributed along the downstream Yichang reach could be affected. This study examined the effects of TGD on the streamflow, sediment load and channel morphology downstream based on in situ measured data. Results showed that, after the impoundment of the TGD, sediment load at the downstream Yichang hydrological station decreased significantly, and the Yichang reach continued to be scoured. The distribution of erosion was uneven, and the scouring mainly occurred in the branching channels. The channel gradient and riverbed roughness increased with the erosion of the river cross section. After more than 10 years of erosion, the riverbed scouring and armouring in the Yichang reach was basically completed, thus we expected that the spawning grounds of Chinese sturgeon could be retain as the riverbed tends to be stable. The findings in this work have implications in the protection of the critically endangered Chinese sturgeon.

Hydrological Regime of the Lower Volga River under Modern Conditions

2018 ◽  
Vol 43 (10) ◽  
pp. 646-654
Author(s):  
O. V. Gorelits ◽  
G. S. Ermakova ◽  
P. N. Terskii
Keyword(s):  
Hydrological Regime ◽  
Volga River ◽  
Lower Volga

Study on Erosion Resistance of Structural Ceramics

2007 ◽  
Vol 280-283 ◽  
pp. 1323-1326
Author(s):  
Chong Gao Bao ◽  
Wei Pan ◽  
He Zhuo Miao ◽  
Long Hao Qi
Keyword(s):  
Erosion Resistance ◽  
Failure Mechanisms ◽  
Ceramic Materials ◽  
Solid Particles ◽  
Failure Pattern ◽  
Structural Ceramics ◽  
Crystal Boundary ◽  
Binding Phase ◽  
Rotary Disk ◽  
Main Factors

The erosion resistance performances of high-Cr cast iron Cr15Mo3 and three kinds of structural ceramics, a-Al2O3, ZTA, Si3N4, were investigated in flowing suspensions of solid particles with a rotary disk erosion wear tester. The microcosmic failure mechanisms of their wear surfaces were analyzed. The results showed that the erosion resistance of Si3N4, ZTA, a-Al2O3 is 21.8, 8.2, 5.6 times than that of Cr15Mo3 respectively. For ceramic materials, toughness and strength are two main factors that affect erosion resistance rather than hardness. The wear rate of ceramic materials is in proportion to the strength and the biquadratic toughness. Due to erosion, Cr15Mo3 is worn out most in the whole, the erosion holes are very clear and its failure pattern is in “W” shape. The wear of ZTA and Al2O3 mainly occurs in the binding phase of the crystal boundary. Thus, the crystal grains are exposed, but without breaks and cracks. The failure pattern is in the shape of “U”. Si3N4 only loses some binding phase of the crystal boundary and the erosion surface is smooth.

IMPACT OF FUTURE CLIMATE CHANGE (2020–2059) ON THE HYDROLOGICAL REGIME IN THE HEIHE RIVER BASIN IN SHAANXI PROVINCE, CHINA

2019 ◽  
Vol 01 (01) ◽  
pp. 1950003 ◽  
Author(s):  
AIDI HUO ◽  
XIAOFAN WANG ◽  
YUXIANG CHENG ◽  
CHUNLI ZHENG ◽  
CHENG JIANG
Keyword(s):  
Climate Change ◽  
Water Resources ◽  
River Basin ◽  
Hydrological Regime ◽  
Annual Runoff ◽  
Heihe River Basin ◽  
Shaanxi Province ◽  
Future Climate Change ◽  
Heihe River ◽  
The Heihe River Basin

Assessing the impacts of climate change on hydrological regime and associated social and economic activities (such as farming) is important for water resources management in any river basin. In this study, we used the popular Soil and Water Assessment Tool (SWAT) to evaluate the impacts of future climate change on the availability of water resources in the Heihe River basin located within Shaanxi Province, China, in terms of runoff and streamflow. The results show that over the next 40 years (starting in 2020 till 2059), changes in the averaged annual runoff ratio are approximately [Formula: see text]11.0%, [Formula: see text]6.4%, 7.2%, and 20.4% for each of the next four consecutive decades as compared to the baseline period (2010–2019). The predicted annual runoff demonstrates an increase trend after a reduction and may result in increased drought and flood risk in the Heihe River basin. To minimize or mitigate these impacts, various adaptation methods have been proposed for the study area, such as stopping irrigation, flood control operation; reasonable development and utilization of regional underground water sources should be implemented in Zhouzhi county and Huyi region in the lower reaches of Heihe River basin.

Sedimentation at different time scales in Yellow River delta in response to course shift and water-sediment regulation

2020 ◽  
Author(s):  
Qiao Shuqing ◽  
Shi Xuefa ◽  
Yonggui Yu ◽  
Limin Hu ◽  
Lin Zhou ◽  
...  
Keyword(s):  
Sediment Load ◽  
Yellow River ◽  
Yellow River Delta ◽  
River Channel ◽  
River Delta ◽  
The Yellow River ◽  
Hydrodynamic Conditions ◽  
Delta Area ◽  
Fluvial Sediment ◽  
High Sediment

<p>The fluvial sediment to the sea is the base of coastal geomorphology and biogeochemical processes, and its transport is an important pathway to the global biogeochemical cycle. The Yellow River is one of globally well-known large rivers because of high sediment load and Chinese Mother River. Its channel shifts frequently because of high sediment load and steep river-channel gradient in the lower reaches . The terminal channel has shifted more than 50 times since 1855 and the last two changes in 1976 and 1996. Furthermore, Yellow River Conservancy Commission has began to implement Water-Sediment Regulation Scheme (WSRS) since 2002, to increase the main channel discharge capacity and to reduce deposition in the reservoirs and river channel. Surface sediment, multi-core and gravity sediment cores, remote sensing images and bathymetric data near the Yellow River delta were collected to study the impact of WSRS and river terminal change together with the water and sediment discharge at the gauging station. Especially, <sup>7</sup>Be, <sup>210</sup>Pb and <sup>137</sup>Cs, grain size, sediment color and TOC/TN was measured to show sedimentary record of WSRS and channel shift on inter-and intra-annual time scale. The results show that the fresh sediment from Yellow River  during 2014 WSRS period can be transported eastward more than 80 km off the rivermouth, while cannot pass 38° easily. Meanwhile the sediment can penetrate as deep as 12 cm. The subaerial delta area is mostly stable after 2002, and its balance is mainly controlled by the surrounding artificial coastline. The subaqueous delta changed from trapping about 4.6×10<sup>8</sup> t to being eroded ~ 3.1×10<sup>8</sup> t and 1.1×10<sup>8</sup> t each year during the three stages of 1976-1996, 1996-2002 and 2002-2014. It is proposed that the subaerial delta area will change little except for the Q8 outlet area, while the subaqueous delta evolution mostly depend on the Huanghe material besides the hydrodynamic conditions. In addition, the aim of WSRS to scour the lower riverbed will recede in future. This study deepens our understanding of the fluvial sediment disperse pattern and sedimentation under the influence of human activities and hydrodynamic conditions.</p><div>Acknowledgements</div><div> <div>This study was supported by National Programme on Global Change and Air-Sea Interaction (GASI-GEOGE-03) and the Natural Science Foundation of China (U1606401).</div> </div>

Analysis for the Characteristics of Sediment in Tarim River

2014 ◽  
Vol 641-642 ◽  
pp. 25-28
Author(s):  
Shao Yun Deng
Keyword(s):  
Sediment Transport ◽  
Sediment Load ◽  
Sediment Concentration ◽  
Annual Runoff ◽  
Tarim River ◽  
Main Stream ◽  
Water Network ◽  
Annual Average ◽  
Sediment Distribution ◽  
Annual Sediment

The author had given a brief introduction of Tarim River, and the analysis of its water network and the surrounding environmental features, and a few important representative of Tarim River tributaries and the main stream of the four major hydrological stations measured runoff for many years, the annual runoff, the average annual sediment load, the annual sediment load, the annual average sediment concentration, the annual sediment concentration, the average annual sediment transport modulus, the annual sediment transport modulus index data were analyzed. And on this basis, the author had given the further analysis of Tarim River stream sediment distribution characteristics, and had described the sediment source and characteristics of Tarim River.

scholarly journals Analysis of possible impacts of climate change on the hydrological regimes of different regions in Germany

2009 ◽  
Vol 21 ◽  
pp. 3-11 ◽  
Author(s):  
H. Bormann
Keyword(s):  
Climate Change ◽  
Soil Moisture ◽  
Groundwater Recharge ◽  
Climate Model ◽  
Hydrological Regime ◽  
Annual Runoff ◽  
Northwest Germany ◽  
East German ◽  
Hydrological Regimes ◽  
Lower Rhine

Abstract. In this study, the impact of climate change scenarios on the hydrological regimes of five different regions in Germany is investigated. These regions (Northwest Germany, Northeast Germany and East German basins, upper and lower Rhine, pre-Alps) differ with respect to present climate and projected climate change. The physically based SVAT-model SIMULAT is applied to theoretical soil columns based on combinations of land use, soil texture and groundwater depth to quantify climate change effects on the hydrological regime. Observed climate, measured at climate stations of the German Weather Service (1991–2007), is used for comparison with climate projections (2071–2100) generated by the regional scale climate model WETTREG. While all climate scenarios implicate an increase in precipitation in winter, a decrease in precipitation in summer and an increase in temperature, the simulated impacts on the hydrological regime are regionally different. In the Rhine region and in Northwest Germany, an increase in the annual runoff and groundwater recharge is simulated despite the increase in temperature and potential evapotranspiration. In the Eastern part of Germany and the pre-Alps, annual runoff and groundwater recharge will decrease. Due to dry conditions in summer, the soil moisture deficit will increase (in Northeast Germany and the East German basins in particular) or remain constant (Rhine region). In all regions the seasonal variability in runoff and soil moisture status will increase. Despite regional warming actual evapotranspiration will decrease in most regions except in areas with shallow groundwater tables and the lower Rhine. Although the study is limited by the fact that only one climate model was used to drive one hydrologic model, the study shows that the hydrological regime will be affected by climate change. The direction of the expected changes seems to be obvious as well as the necessity of the adaptation of future water management strategies.

scholarly journals Analysis Of Reed Resource Dynamics In Water Bodies Of Eastern Latvia

2015 ◽  
Vol 1 ◽  
pp. 252
Author(s):  
E. Čubars ◽  
G. Noviks
Keyword(s):  
Shallow Lakes ◽  
Water Body ◽  
Human Activities ◽  
Hydrological Regime ◽  
Climatic Conditions ◽  
Water Bodies ◽  
Natural Processes ◽  
Resource Dynamics ◽  
Main Factors ◽  
Made In

The paper shows the results obtained during the research of reed dynamics revealing that in Eastern Latvia 20 lakes and pisciculture farms are potentially important for the reed extraction. In 2008, the reed resources there covered a territory of approximately 2300 ha. The ortophoto images of potentially important water bodies made in 1997, 2005 and 2008 were analyzed using the computer program ArcMap. The reed growth develops differently in every water body, but in general the eutrophication of water bodies and the enlargement of reed-covered areas can be observed. The most rapidly the reed occupies new territories in pisciculture farms and shallow lakes. The analysis of reed resource dynamics show that reed-covered areas in this region are expanding every year. The main factors that influence the distribution of reed growths refer to human activities, climatic conditions, hydrological regime in water bodies and natural processes of eutrophication.

Sign in / Sign up

Export Citation Format

Share Document