scholarly journals City flood disaster scenario simulation based on 1D-2D coupled rain-flood model: A case study in Luoyang, China.

2021 ◽  
Author(s):  
Chengshuai Liu ◽  
Fan Yang ◽  
caihong hu ◽  
Yichen Yao ◽  
Yue Sun ◽  
...  
Keyword(s):  
Relative Error ◽  
Water Depth ◽  
Absolute Error ◽  
Average Relative Error ◽  
Two Dimensional ◽  
Average Absolute Error ◽  
Urban Flood ◽  
One Dimensional ◽  
Rainfall Duration ◽  
Flood Model

In order to realize the reproduction and simulation of urban rainstorm and waterlogging scenarios with complex underlying surfaces. Based on the Mike series models, we constructed an urban storm-flood coupling model considering one-dimensional river channels, two-dimensional ground and underground pipe networks. Luoyang City was used as a pilot to realize the construction of a one-dimensional and two-dimensional coupled urban flood model and flood simulation. where is located in the western part of Henan Province, China. The coupled model was calibrated and verified by the submerged water depths of 16 survey points in two historical storms flood events. The average relative error of the calibration simulated water depth was 22.65%, and the average absolute error was 13.93cm; the average relative error of the verified simulated water depth was 15.27%, The average absolute error is 7.54cm, and the simulation result is good. Finally, 28 rains with different return periods and different durations were designed to simulate and analyze the rainstorm inundation in the downtown area of Luoyang. The result shows that the R2 of rainfall and urban rainstorm inundation is 0.8776, and the R2 of rainfall duration and urban rainstorm inundation is 0.8141. Therefore, rainfall is the decisive factor in the formation of urban waterlogging disasters, which is actually the rainfall duration. The study results have important practical significance for urban flood prevention, disaster reduction and traffic emergency management.

scholarly journals Verification of a Nondestructive Method for Assessing the Humidity of Saline Brick Walls in Historical Buildings

2020 ◽  
Vol 10 (19) ◽  
pp. 6926
Author(s):  
Anna Hoła ◽  
Łukasz Sadowski
Keyword(s):  
Neural Network ◽  
Relative Error ◽  
Absolute Error ◽  
Nondestructive Method ◽  
Historic Buildings ◽  
Average Absolute Error ◽  
Artificial Neural Network Ann ◽  
Very High ◽  
Construction Practice

The paper presents the results of the verification of the neural method for assessing the humidity of saline brick walls. The method was previously developed by the authors and can be useful for the nondestructive assessment of the humidity of walls in historic buildings when destructive intervention during testing is not possible due to conservation restrictions. However, before being implemented in construction practice, this method requires validation by verification on other historic buildings, which to date has not been done. The paper presents the results of such verification, which has never been carried out before, and thus extends the scope of knowledge related to the issue. For experimental verification of the artificial neural network (ANN), the results of moisture tests of two selected historic buildings, other than those used for ANN learning and testing processes, were used. An artificial unidirectional multilayer neural network with backward error propagation and the algorithm for learning conjugate gradient (CG) was found to be useful for this purpose. The obtained satisfactory value of the linear correlation coefficient R of 0.807 and low average absolute error |Δf| of 1.16% confirms this statement. The values of average relative error |RE| of 19.02%, which were obtained in this research, were not very high for an in-situ study. Moreover, the relative error values |RE| were mostly in the range of 15% to 25%.

Courtyard-level sewer data-enhanced two-dimensional hydraulic model for urban flood hazard assessment in Kunming, China

Water Policy ◽  
2014 ◽  
Vol 17 (1) ◽  
pp. 143-161
Author(s):  
Zhiqiang Xie ◽  
Qingyun Du ◽  
Zhongliang Cai ◽  
Huaixiang Liu ◽  
Sam Jamieson
Keyword(s):  
Statistical Method ◽  
Urban Areas ◽  
Flood Hazard ◽  
Ground Surface ◽  
Hydraulic Model ◽  
Two Dimensional ◽  
Urban Flood ◽  
One Dimensional ◽  
Municipal Level ◽  
Overlay Approach

This paper describes a study of urban flooding in downtown Kunming, China, simulating a major flood event that occurred in July 2008 using an improved two-dimensional (2D) hydraulic model enhanced with courtyard-level sewer data (CLSD). Although municipal authorities are not responsible for ‘private’ courtyard sewers, available records were specifically added to this model, enhancing its accuracy and usefulness. Geographic information system (GIS) flood maps, a mapping overlay approach and statistical method compared both predicted results and the recorded flood area. A statistical method also provided a measure of the correlation between the extent of the predicted flood areas and recorded flood areas (parameter ‘F’). Results of the improved 2D/CLSD model showed a correlation value for F of 51, 32.6% higher than the basic one-dimensional municipal-level sewer data (1D/MLSD) model; 26.2% higher than an interim version of the model that included a 2D ground surface (2D/MLSD). The 2D/CLSD model predicted flooding in 10 of the 12 courtyards with observed flooding. This was a major improvement over the 1D/MLSD model (three out of 12) and the 2D/MLSD model (five out of 12). Thus a CLSD-enhanced 2D hydraulic model potentially improves accuracy in predicting, mapping and understanding flood risk in urban areas.

Calibration of a 1D/1D urban flood model using 1D/2D model results in the absence of field data

2011 ◽  
Vol 64 (5) ◽  
pp. 1016-1024 ◽  
Author(s):  
J. Leandro ◽  
S. Djordjević ◽  
A. S. Chen ◽  
D. A. Savić ◽  
M. Stanić
Keyword(s):  
Field Data ◽  
Computational Time ◽  
Necessary Condition ◽  
Two Dimensional ◽  
Time Step ◽  
Urban Flood ◽  
One Dimensional ◽  
1D Model ◽  
Surface Network ◽  
2D Model

Recently increased flood events have been prompting researchers to improve existing coupled flood-models such as one-dimensional (1D)/1D and 1D/two-dimensional (2D) models. While 1D/1D models simulate sewer and surface networks using a one-dimensional approach, 1D/2D models represent the surface network by a two-dimensional surface grid. However their application raises two issues to urban flood modellers: (1) stormwater systems planning/emergency or risk analysis demands for fast models, and the 1D/2D computational time is prohibitive, (2) and the recognized lack of field data (e.g. Hunter et al. (2008)) causes difficulties for the calibration/validation of 1D/1D models. In this paper we propose to overcome these issues by calibrating a 1D/1D model with the results of a 1D/2D model. The flood-inundation results show that: (1) 1D/2D results can be used to calibrate faster 1D/1D models, (2) the 1D/1D model is able to map the 1D/2D flood maximum extent well, and the flooding limits satisfactorily in each time-step, (3) the 1D/1D model major differences are the instantaneous flow propagation and overestimation of the flood-depths within surface-ponds, (4) the agreement in the volume surcharged by both models is a necessary condition for the 1D surface-network validation and (5) the agreement of the manholes discharge shapes measures the fitness of the calibrated 1D surface-network.

Minimizing Error in Measurement of Error: A Proposed Method for Calculation of Error in a Two-Dimensional Motor Task

2000 ◽  
Vol 90 (1) ◽  
pp. 253-261 ◽  
Author(s):  
Jingu Kim ◽  
Sangtak Chung ◽  
L. Keith Tennant ◽  
Robert N. Singer ◽  
Christopher M. Janelle
Keyword(s):  
Motor Task ◽  
Absolute Error ◽  
Two Dimensional ◽  
Dimensional Error ◽  
One Dimensional ◽  
Radial Error ◽  
Variable Error ◽  
Total Variability ◽  
Accurate Procedure ◽  
Novel Method

Traditional one-dimensional error scores are still consistently used in research on motor learning to quantify two-dimensional error; however, the inherent differences in two-dimensional tasks render that application inappropriate and often misleading. Consequently, the purpose of this paper was to propose a novel method of presenting errors, which more precisely represents the accuracy, direction, and variability of error in two-dimensional settings. Although closely related to several alternatives for representing errors, the methodology used and the results obtained provide a more accurate procedure for pinpointing critical trends in what have been commonly referred to as AE (absolute error), VE (variable error), CE (constant error), and E (total variability). The proposed measurements of AVE (adjusted variable error), DE (directional error), TSE (total spread of error), and RE (radial error) provide composite error scores carrying a variety of information about performance on two-dimensional tasks. Formulas and examples are provided to facilitate computation and enhance understanding of the proposed scores.

scholarly journals Effect of Vegetation Roots on the Threshold of Slope Instability Induced by Rainfall and Runoff

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-19
Author(s):  
Gang Huang ◽  
Mingxin Zheng ◽  
Jing Peng
Keyword(s):  
Factor Of Safety ◽  
Rainfall Amount ◽  
Slope Instability ◽  
Two Dimensional ◽  
Drying Time ◽  
One Dimensional ◽  
Rainfall Duration ◽  
Safe Area ◽  
The Stability ◽  
Dimensional Instability

Although vegetation is increasingly used to mitigate landslide risks, how vegetation roots affect the landslide threshold of slope has rarely been explored, particularly in the case of lateral runoff. In this study, we established a two-dimensional saturated-unsaturated infiltration equation considering the hydraulic effects of vegetation roots. The analytical solution for the shallow unsaturated two-dimensional coupled infiltration of vegetated slope (VS) was obtained by a Fourier transform technique. The numerical method was used to evaluate the stability of VS caused by four root architectures, the rainfall amount, and the rainfall duration. Subsequently, the transformation law in runoff, vegetation evaporation, and landslide threshold was analyzed. The results indicate that the factor of safety (FOS) increases with increasing drying time and decreases with increasing depth; the minimum FOS is at the junction of the root-rootless zone. Runoff and vegetation evaporation are favorable for the shallow stability of VS. The time of the safe area is 35 h for rainfall amount 500 m in the uniformly root clay slope. Moreover, four landslide threshold curves that reflected the root architecture, rainfall amount, and rainfall duration are developed, which are more realistic than those created using one-dimensional instability modeling.

A one-dimensional self-gravitating stellar gas

1966 ◽  
Vol 25 ◽  
pp. 46-48 ◽  
Author(s):  
M. Lecar
Keyword(s):  
Gravitational Field ◽  
Phase Space ◽  
Motion Picture ◽  
Space Distribution ◽  
Two Dimensional ◽  
One Dimensional ◽  
Phase Space Distribution ◽  
Dimensional Phase Space ◽  
The Mean

“Dynamical mixing”, i.e. relaxation of a stellar phase space distribution through interaction with the mean gravitational field, is numerically investigated for a one-dimensional self-gravitating stellar gas. Qualitative results are presented in the form of a motion picture of the flow of phase points (representing homogeneous slabs of stars) in two-dimensional phase space.

State-of-the-Art of Modeling Surface Water Impoundments

1982 ◽  
Vol 14 (1-2) ◽  
pp. 241-261 ◽  
Author(s):  
P A Krenkel ◽  
R H French
Keyword(s):  
Water Quality ◽  
Surface Water ◽  
State Of The Art ◽  
Rate Coefficients ◽  
Two Dimensional ◽  
One Dimensional ◽  
Integral Energy ◽  
Range Of Values ◽  
Dimensional Integral ◽  
Water Impoundment

The state-of-the-art of surface water impoundment modeling is examined from the viewpoints of both hydrodynamics and water quality. In the area of hydrodynamics current one dimensional integral energy and two dimensional models are discussed. In the area of water quality, the formulations used for various parameters are presented with a range of values for the associated rate coefficients.

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