scholarly journals PHYSICAL MODELLING SIMILITUDE : A STUDY OF SEDIMENT DEPOSITION IN RESERVOIR

2020 ◽  
Vol 80 (2) ◽  
Author(s):  
Safari Mat Desa ◽  
Mohd Kamarul Huda Samion ◽  
Mohd Hidayat Jamal ◽  
Ahmad Farhan Hamzah ◽  
Ernie Abd Manan ◽  
...  
Keyword(s):  
Flood Control ◽  
Morphological Changes ◽  
Fixed Bed ◽  
Physical Modelling ◽  
Infrastructure Development ◽  
Check Dam ◽  
Bed Sediment ◽  
Rapid Urbanization ◽  
Local Flow ◽  
Sediment Control

Changes in rainfall pattern, rapid urbanization, infrastructure development and uncontrolled agricultural activities have been found as major sources to contribute to excessive reservoir sedimentation problem in Malaysia, thus significantly shorten the design life of a reservoir. Hence, reservoir functions have deteriorated, such as reduction in power generation capacity, additional lateral load affected to dam stability and decrease in storage capacity for flood control. The objective of this study is to model, simulate and propose alternative method for sediment removal control in Ringlet Reservoir. The construction of physical model of Ringlet Reservoir took place in the Hydraulic and Instrumentation Laboratory, National Hydraulic Research Institute of Malaysia (NAHRIM), with geometric similitude of 1:30. Three different average recurrent intervals (ARI) of 1, 5 and 100 were tested at Sungai Habu and Ringlet. Groyne was identified as a control mitigation structure for sediment control, and a total of 23 groynes were constructed. Physical modelling execution explicitly showed the gross deposition and erosion is linear as the return period rose. Bed sediment for a 100 year ARI was eroded more than that of 1 and 5 year ARI, due to local scour resulting from the flow transition from fixed bed to mobile bed. At Ringlet, sediment was deposited mostly before the first check dam for 1 year ARI. For 5 and 100 ARI, sediment was further transported before the second check dam. Finding in Habu, showed morphological changes was due to the local flow. The movement of bed sediment at the end of Habu, were deposited much early before the check dam, thus not travelling further downstream. Geometrical similitude of this modelling was carried out successfully, and gained recognition from the Malaysia Book of Records as the Biggest Hydraulic Model.

River networks system changes and its impact on storage and flood control capacity under rapid urbanization

2016 ◽  
Vol 30 (13) ◽  
pp. 2401-2412 ◽  
Author(s):  
Liu Yang ◽  
Youpeng Xu ◽  
Longfei Han ◽  
Song Song ◽  
Xiaojun Deng ◽  
...  
Keyword(s):  
Flood Control ◽  
River Networks ◽  
Rapid Urbanization ◽  
System Changes

Rapid urbanization and the growing demand for urban infrastructure in Africa

2017 ◽  
Author(s):  
Charles Leyeka Lufumpa ◽  
Tito Yepes
Keyword(s):  
Agricultural Productivity ◽  
Complex Task ◽  
Infrastructure Development ◽  
Transformation Theory ◽  
African Countries ◽  
Institutional Reforms ◽  
Rapid Urbanization ◽  
Urban Transition ◽  
Development Agenda

Africa is undergoing a rapid urban transition and is set to be the fastest urbanizing region in the coming decades. This shift has profound implications for achieving the continental and global targets for inclusive growth and transformation. Theory and global experience show that urbanization and structural transformation are closely linked—but less so in Africa. Urbanization in many African countries has not been driven by improving agricultural productivity. Indeed, most countries are urbanizing rapidly amid declining or stagnant industrial output and low agricultural productivity. The infrastructure development agenda has to make cities more productive and liveable yet with great reliance on the provision of sizable resources. However, matching the investment agenda to the goals of urbanization is a complex task, encompassing regional, national, urban, and rural dimensions which together determine the quality of the urbanization process. Institutional reforms should be undertaken to positively drive urbanization in Africa.

scholarly journals Benefits of Embungs in the Rawa Pening Catchment Area for Reducing Tuntang River Flood Discharge

2018 ◽  
Vol 73 ◽  
pp. 08029
Author(s):  
Darsono Suseno ◽  
S Suripin ◽  
Budieny Hary ◽  
Cholifatul Afifah Risdiana ◽  
Pujiastuti Ratih ◽  
...  
Keyword(s):  
Catchment Area ◽  
Flood Control ◽  
Water Source ◽  
Raw Water ◽  
Sediment Control ◽  
Resources Management ◽  
Control Sediment ◽  
Central Java ◽  
Flood Discharge ◽  
River Flood

Rawa Pening is a natural lake as a source of water for Tuntang River which is used for hydropower, raw water source, main irrigation water source in Glapan weir located in Grobogan District, Central Java provinces. Rawa Pening will be developed as location of national and international ecotourism. An Optimal Water Resources Management is required with several studies. This study is the beginning of a series of studies planned to determine the potential of embungs and its utilization as flood control, sediment control of Rawa Pening and for reducing weeds growth.

scholarly journals Changes in stage–flow relation of the East River, the Pearl River basin: causes and implications

2012 ◽  
Vol 44 (4) ◽  
pp. 737-746 ◽  
Author(s):  
Qiang Zhang ◽  
Kun Li ◽  
Vijay P. Singh ◽  
Xiaohong Chen ◽  
Jianfeng Li
Keyword(s):  
Water Level ◽  
River Basin ◽  
Flood Control ◽  
Morphological Changes ◽  
River Channel ◽  
Pearl River Basin ◽  
Abrupt Decrease ◽  
East River ◽  
The Pearl River ◽  
High Level

Water level and streamflow extracted from 891 hydrological episodes from both dry and flood seasons covering a period of 1954–2009 were analyzed to investigate stage–flow relations. Results indicate the following. (1) Since the early 1990s the low/high flow is increasing/decreasing. The water level, particularly the high level, is consistently decreasing. An abrupt decrease of water level is observed since the early 1990s at the lower East River. (2) Stage–streamflow relation is usually stable in the river reach with no significant bedform morphological changes. Changes in the geometric shape of the river channel are the major cause of the change in the stage–streamflow relation. (3) An abrupt decrease of water level at the Boluo station is mainly the result of abnormally rapid downcutting of the riverbed due to extensive sand dredging within the channel which caused serious headwater erosion. This human-induced modification by downcutting of the river channel may lead to significant hydrological alterations and may have critical implications for flood control, conservation of eco-environment, and also for basin-wide water resources management in the lower East River basin.

scholarly journals The influence of large wood and rootwad on flow patterns and bed morphology in a moving bed channel

2018 ◽  
Vol 40 ◽  
pp. 02044
Author(s):  
Su-Chin Chen ◽  
Min-Chih Liang ◽  
Samkele Tfwala
Keyword(s):  
Field Experiments ◽  
Morphological Changes ◽  
Fixed Bed ◽  
Flow Patterns ◽  
Large Wood ◽  
River Channels ◽  
Moving Bed ◽  
Bed Topography ◽  
Bed Elevation ◽  
Elevation Changes

Studying large wood in river channels can help gain insight on their form and processes. Over the preceding decade, laboratory and field experiments have been used to explain wood dynamics, flow patterns and sediment transport. Moreover, field experiments are sparse, while laboratory experiments have focused mostly on fixed bed to capture their entrainment. To enhance our scientific understanding on logs of different morphology, this study designed an experimental flume to investigate the effects of log presence on flow and bed topography in a moving bed channel. Two log configurations were used, with and without rootwad. Wood pieces had a length of 0.2 m, diameter 0.05 m and a density of approximately 760 kg/m3. Rootwad were simulated by joining 0.06 m wood pieces, having a diameter of 0.02 m to the base of the log pieces at an angle of 30°. The experiments were carried out in a 4 m long flume, 0.6 m width and 0.6 m deep, and having a slope of 0.001. The experimental bed zone was paved with uniform sand, d50 = 0.750 mm, of 0.1 m thickness. Flow in the channel was set such that it was below the critical flow for wood entrainment, and it ranged between 0.0015 to 0.005 m3/s. Three different orientations of the log were considered, namely parallel, oblique and transverse to flow. Bed evolution was monitored using a camera and a laser mounted on a moving motor frame. This research shows that log orientation and the presence of rootwad dictate bed elevation changes and stability of single wood pieces. In addition, the contrast of morphological changes caused by the presence of abundant wood in a moving bed is crucial in determining large wood appropriate for river restoration. Our study provokes fascinating questions for future investigations.

scholarly journals Flood Risk Zoning by Using 2D Hydrodynamic Modeling: A Case Study in Jinan City

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Tao Cheng ◽  
Zongxue Xu ◽  
Siyang Hong ◽  
Sulin Song
Keyword(s):  
Flood Risk ◽  
Flood Control ◽  
Overland Flow ◽  
The South ◽  
Rapid Urbanization ◽  
Risk Zoning ◽  
The North ◽  
Hourly Rainfall ◽  
Infoworks Icm ◽  
Jinan City

Climate change and rapid urbanization have aggravated the rainstorm flood in Jinan City during the past decades. Jinan City is higher in the south and lower in the north with a steep slope inclined from the south to the north. This results in high-velocity overland flow and deep waterlogging, which poses a tremendous threat to pedestrians and vehicles. Therefore, it is vital to investigate the rainstorm flood and further perform flood risk zoning. This study is carried out in the “Sponge City Construction” pilot area of Jinan City, where the InfoWorks ICM 2D hydrodynamic model is utilized for simulating historical and designed rainfall events. The model is validated with observations, and the causes for errors are analyzed. The simulated water depth and flow velocity are recorded for flood risk zoning. The result shows that the InfoWorks ICM 2D model performed well. The flood risk zoning result shows that rainfalls with larger recurrence intervals generate larger areas of moderate to extreme risk. Meanwhile, the zoning results for the two historical rainfalls show that flood with a higher maximum hourly rainfall intensity is more serious. This study will provide scientific support for the flood control and disaster reduction in Jinan City.

Study on the Local Scouring of the Bridge with Sediment Control Dam

2012 ◽  
Vol 204-208 ◽  
pp. 2230-2235 ◽  
Author(s):  
Dong Po Sun ◽  
Li Sha Wang ◽  
Peng Tao Wang
Keyword(s):  
Model Experiment ◽  
Multivariate Regression ◽  
Flood Control ◽  
Influence Factors ◽  
Control Design ◽  
Multivariate Regression Analysis ◽  
Shallow Foundation ◽  
The Other ◽  
Sediment Control ◽  
Approach Velocity

Based on the characteristics of local piers scouring after built the sediment control dam in the downstream of the bridge, by the monomer model experiment of flume, sixty groups of local piers scouring experiments have been carried on.The principle and the influence factors of the local piers scouring have been analyzed. The results of series model experiments show that, with the sediment control dams, the local scouring of the piers, on one hand, is influenced by the approach velocity, down-shearing vortex, dimension of the piers, diameter and gradation of the bed sand; on the other hand, it is affected by the elevation of the dam and distance between the pier and the dam. Therefore, the concept of “control slope” is introduced in order to reflect the impacts of the sediment control dam to the piers. Based on the theoretical deduction and dimensional analysis, the equation, which is used to calculate the local scouring with no-uniform bed sand, is acquired by multivariate regression analysis, has been testified by the flume experiment and has got a good result. The optimum value of control slope and the equation of local piers scouring with that dam provide valuable references for bridge flood-control design of the shallow foundation with downstream sediment control dam.

scholarly journals Cross-plane stereo-PIV measurements in a refractive-index-matched environment of flow associated with barchan dunes immersed in a turbulent boundary layer

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Nathaniel Bristow ◽  
Gianluca Blois ◽  
James Best ◽  
Kenneth Christensen
Keyword(s):  
Boundary Layer ◽  
Refractive Index ◽  
Turbulent Boundary Layer ◽  
Coherent Structures ◽  
Fixed Bed ◽  
Flow Structures ◽  
Local Flow ◽  
Piv Measurements ◽  
Complex Interactions ◽  
Barchan Dunes

Barchan dunes are crescent-shaped bedforms that form in aeolian (i.e., wind-driven) environments (including both Earth and other planets, such as Mars) as well as subaqueous environments. Under the forcing of the aloft turbulent boundary layer, they migrate downstream at a rate inversely proportional to their size, which results in complex interactions between neighboring dunes of disparate scales. In particular, it has been observed that dunes will interact at a distance, causing changes in morphology without contacting each other, which is thought to be driven by the way dunes modify the local flow field Bristow et al. (2018); Assis and Franklin (2020). In this study, the coherent structures formed in the wakes of barchan dunes are investigated using measurements of the flow over fixed-bed (i.e., solid) barchan models, both in the wake of an isolated barchan and the interdune region between interacting barchans (Fig. 1(a)). Furthermore, the interactions between the flow structures shed by the dunes and the structures in the incoming boundary layer are analyzed.

scholarly journals Application of Edge Computing Technology in Hydrological Spatial Analysis and Ecological Planning

2021 ◽  
Vol 18 (16) ◽  
pp. 8382
Author(s):  
Xinhong Cai ◽  
Dawei Xu
Keyword(s):  
Spatial Analysis ◽  
Flood Control ◽  
Water Source ◽  
Edge Computing ◽  
Planning Method ◽  
Ecological Problem ◽  
Ecological Planning ◽  
Computing Technology ◽  
Core Element ◽  
Rapid Urbanization

The process of rapid urbanization causes so many water security issues such as urban waterlogging, environmental water pollution, water shortages, etc. It is, therefore, necessary for us to integrate a variety of theories, methods, measures, and means to conduct ecological problem diagnosis, ecological function demand assessment, and ecological security pattern planning. Here, EC (Edge Computing) technology is applied to analyze the hydrological spatial structure characteristics and ecological planning method of waterfront green space. First, various information is collected and scientifically analyzed around the core element of ecological planning: water. Then, in-depth research is conducted on the previous hydrological spatial analysis methods to identify their defects. Subsequently, given these defects, the EC technology is introduced to design a bottom-up overall architecture of intelligent ecological planning gateway, which can be divided into field devices, EC intelligent planning gateway, transmission system, and cloud processing platform. Finally, the performance of the overall architecture of the intelligent ecological planning gateway is tested. The study aims to optimize the performance of the hydrological spatial analysis method and ecological planning method in Xianglan town of Jiamusi city. The results show that the system can detect the flood control safety system planning, analysis of water source pollution. Additionally, the system also can use the EC technology, depending on the types, hydrological characteristics, pollutants to predict treatment sludge need to put in the pollutant treatment medicament composition and dosage, protection of water source nearby residents public health security. Compared with previous hydrological spatial analysis and ecological planning methods, the system is more scientific, efficient, and expandable. The results provide a technical basis for the research in related fields.

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