scholarly journals Estimation of rainfall threshold for flood warning for small urban watersheds based on the 1D–2D drainage model simulation

2021 ◽  
Author(s):  
Duc Anh Dao ◽  
Dongkyun Kim ◽  
Dang Hai Ha Tran
Keyword(s):  
Model Simulation ◽  
Rainfall Threshold ◽  
Urban Watersheds ◽  
Flood Warning

scholarly journals Estimation of Rainfall Threshold for Flood Warning for Small Urban Watersheds Based on the 1D-2D Drainage Model Simulation

2021 ◽  
Author(s):  
Duc Anh Dao ◽  
Dongkyun Kim ◽  
Dang Hai Ha Tran
Keyword(s):  
Temporal Variability ◽  
Model Simulation ◽  
Warning System ◽  
Curve Number ◽  
Rainfall Threshold ◽  
Urban Watersheds ◽  
Storm Events ◽  
Rainfall Events ◽  
Flood Warning ◽  
Flood Warning System

Abstract This study proposed an equation for Rainfall Threshold for Flood Warning (RTFW) for small urban watersheds based on computer simulations. First, a coupled 1D-2D dual-drainage model was developed for nine watersheds in Seoul, Korea. Next, the model simulation was repeated for a total of 540 combinations of the synthetic rainfall events and watershed imperviousness (9 watersheds x 4 NRCS Curve Number (CN) values x 15 rainfall events). Then, the results of the 101 simulations that caused the critical flooded depth (0.25m-0.35m) were used to develop the equation that relates the value of RTFW to the rainfall event temporal variability (represented as coefficient of variation or CV) and the watershed Curve Number. The results suggest that (1) RTFW exponentially decreases as the rainfall CV increases; (2) RTFW linearly decreases as the watershed CV increases; and that (3) RTFW is dominated by CV when the rainfall has low temporal variability (e.g., CV<0.2) while RTFW is dominated by CN when the rainfall has high temporal variability (e.g., CV>0.4). For validation, the proposed equation was applied for the flood warning system with two storm events occurred in 2010 and 2011 over 239 watersheds in Seoul. The system showed the the hit, false and missed alarm rates at 69% (48%), 31% (52%) and 6.7% (4.5%), respectively for the 2010 (2011) event.

scholarly journals Rainfall Threshold for Flash Flood Warning Based on Model Output of Soil Moisture: Case Study Wernersbach, Germany

Water ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1061
Author(s):  
Thanh Thi Luong ◽  
Judith Pöschmann ◽  
Rico Kronenberg ◽  
Christian Bernhofer
Keyword(s):  
Soil Moisture ◽  
Flash Flood ◽  
Rainfall Threshold ◽  
Probability Of Detection ◽  
Water Levels ◽  
Critical Success ◽  
Flood Warning ◽  
Critical Discharge ◽  
Critical Success Index

Convective rainfall can cause dangerous flash floods within less than six hours. Thus, simple approaches are required for issuing quick warnings. The flash flood guidance (FFG) approach pre-calculates rainfall levels (thresholds) potentially causing critical water levels for a specific catchment. Afterwards, only rainfall and soil moisture information are required to issue warnings. This study applied the principle of FFG to the Wernersbach Catchment (Germany) with excellent data coverage using the BROOK90 water budget model. The rainfall thresholds were determined for durations of 1 to 24 h, by running BROOK90 in “inverse” mode, identifying rainfall values for each duration that led to exceedance of critical discharge (fixed value). After calibrating the model based on its runoff, we ran it in hourly mode with four precipitation types and various levels of initial soil moisture for the period 1996–2010. The rainfall threshold curves showed a very high probability of detection (POD) of 91% for the 40 extracted flash flood events in the study period, however, the false alarm rate (FAR) of 56% and the critical success index (CSI) of 42% should be improved in further studies. The proposed adjusted FFG approach has the potential to provide reliable support in flash flood forecasting.

scholarly journals Using Tabu Search Adjusted with Urban Sewer Flood Simulation to Improve Pluvial Flood Warning via Rainfall Thresholds

Water ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 348 ◽  
Author(s):  
Hao-Yu Liao ◽  
Tsung-Yi Pan ◽  
Hsiang-Kuan Chang ◽  
Chi-Tai Hsieh ◽  
Jihn-Sung Lai ◽  
...  
Keyword(s):  
Tabu Search ◽  
Overland Flow ◽  
Search Algorithm ◽  
Warning System ◽  
Extreme Rainfall ◽  
Initial Boundary ◽  
Rainfall Threshold ◽  
Hydrodynamic Modeling ◽  
Rainfall Thresholds ◽  
Flood Warning

Pluvial floods are the most frequent natural hazard impacting urban cities because of extreme rainfall intensity within short duration. Owing to the complex interaction between rainfall, drainage systems and overland flow, pluvial flood warning poses a challenge for many metropolises. Although physical-based flood inundation models could identify inundated locations, hydrodynamic modeling is limited in terms of computational costs and sophisticated calibration. Thus, herein, a quick pluvial flood warning system using rainfall thresholds for central Taipei is developed. A tabu search algorithm is implemented with hydrological-analysis-based initial boundary conditions to optimize rainfall thresholds. Furthermore, a cross test is adopted to evaluate the effect of each rainfall event on rainfall threshold optimization. Urban sewer flood is simulated via hydrodynamic modeling with calibration using crowdsourced data. The locations and time of occurrence of pluvial floods can be obtained to increase the quality of observed data that dominate the accuracy of pluvial flood warning when using rainfall thresholds. The optimization process is a tabu search based on flood reports and observed data for six flood-prone districts in central Taipei. The results show that optimum rainfall thresholds can be efficiently determined through tabu search and the accuracy of the issued flood warnings can be significantly improved.

scholarly journals A Bayesian decision approach to rainfall thresholds based flood warning

2006 ◽  
Vol 10 (3) ◽  
pp. 413-426 ◽  
Author(s):  
M. L. V. Martina ◽  
E. Todini ◽  
A. Libralon
Keyword(s):  
Real Time ◽  
Initial Conditions ◽  
Flood Forecasting ◽  
Rainfall Threshold ◽  
Precipitation Forecast ◽  
Bayesian Decision ◽  
Threshold Values ◽  
Flood Warning ◽  
Critical Rainfall ◽  
Forecasting System

Abstract. Operational real time flood forecasting systems generally require a hydrological model to run in real time as well as a series of hydro-informatics tools to transform the flood forecast into relatively simple and clear messages to the decision makers involved in flood defense. The scope of this paper is to set forth the possibility of providing flood warnings at given river sections based on the direct comparison of the quantitative precipitation forecast with critical rainfall threshold values, without the need of an on-line real time forecasting system. This approach leads to an extremely simplified alert system to be used by non technical stakeholders and could also be used to supplement the traditional flood forecasting systems in case of system failures. The critical rainfall threshold values, incorporating the soil moisture initial conditions, result from statistical analyses using long hydrological time series combined with a Bayesian utility function minimization. In the paper, results of an application of the proposed methodology to the Sieve river, a tributary of the Arno river in Italy, are given to exemplify its practical applicability.

scholarly journals Estimation of the Flood Warning Rainfall Threshold Considering Agricultural Reservoirs

2013 ◽  
Vol 13 (2) ◽  
pp. 227-236 ◽  
Author(s):  
Eung Seok Kim ◽  
Kuy Bum Sim ◽  
Jae Beom Park ◽  
Moo Jong Park ◽  
Hyun Il Choi
Keyword(s):  
Rainfall Threshold ◽  
Flood Warning

scholarly journals Analysis of the specific water level of flood control and the threshold value of rainfall warning for small and medium rivers

2020 ◽  
Vol 383 ◽  
pp. 201-211
Author(s):  
Yuzhong Hu ◽  
Zhaoxia Wang ◽  
Bin Zhou ◽  
Shiqi Jiang
Keyword(s):  
Flood Control ◽  
Flash Flood ◽  
Threshold Value ◽  
Rainfall Threshold ◽  
Threshold Values ◽  
Study Region ◽  
Flood Warning ◽  
Variable Characteristic ◽  
Control Capability ◽  
The Relationship

Abstract. In order to fully use the newly-built hydrologic stations in small and medium rivers for flood warning and prevention, based on the technical line of the investigation and evaluation of flash flood disasters, different historical flood information of the warning river section was investigated, while the elevations of riverain houses were measured. The relationship between the stations and affected population has been established for the study region. According to integrated flood control capability of riverside residents, the characteristic water levers and rainfall threshold values were determined in this case. The results indicate that the warning and safety levels are 54.0 and 55.3 m, respectively. The analysis results show that the warning should be issued when the net rainfall intensity is 70 mm h−1 or 110 mm for 6 h condition. And considering the effectiveness of disaster avoidance, variable characteristic water levers of the hydrologic station for flood warning in different village were determined on the basis of the flood control capability of each village. The relationship between hydrologic numerical value and inundating influence was established in a one-to-n way.

scholarly journals Rainfall Threshold for Flash Flood Warning Based on Model Output of Soil Moisture: Case Study Wernersbach, Germany

2021 ◽  
Author(s):  
Thanh Thi Luong ◽  
Judith Pöschmann ◽  
Rico Kronenberg ◽  
Christian Bernhofer
Keyword(s):  
Soil Moisture ◽  
Flash Flood ◽  
Rainfall Threshold ◽  
Probability Of Detection ◽  
Water Levels ◽  
Critical Success ◽  
Flood Warning ◽  
Critical Discharge ◽  
Available Information

Convective rainfall can cause dangerous flash floods within less than six hours. Thus, simple approaches are required for issuing quick warnings. The Flash Flood Guidance (FFG) approach pre-calculates rainfall levels (thresholds) potentially causing critical water levels for a specific catchment. Afterwards, only rainfall and soil moisture information is required to issue warn-ings. This study applied the principle of FFG to the Wernersbach Catchment (Germany) with excellent data coverage using the BROOK90 water budget model. The rainfall thresholds were determined for durations of 1 to 24 hours, by running BROOK90 in “inverse” mode, identifying rainfall values for each duration that led to exceedance of critical discharge (fixed value). After calibrating the model based on its runoff, we ran it in hourly mode with four precipitation types and various levels of initial soil moisture for the period 1996 – 2010. The rainfall threshold curves showed a very high probability of detection (POD) of 91% for the 40 extracted flash flood events in the study period, however, the false alarm rate (FAR) of 56% and the critical success index (CSI) of 42% should be improved in further studies. The approach proved potential as an early flood indicator for head-catchments with limited available information.

scholarly journals A Bayesian decision approach to rainfall thresholds based flood warning

2005 ◽  
Vol 2 (6) ◽  
pp. 2663-2706 ◽  
Author(s):  
M. L. V. Martina ◽  
E. Todini ◽  
A. Libralon
Keyword(s):  
Real Time ◽  
Initial Conditions ◽  
Flood Forecasting ◽  
Rainfall Threshold ◽  
Precipitation Forecast ◽  
Bayesian Decision ◽  
Threshold Values ◽  
Flood Warning ◽  
Critical Rainfall ◽  
Forecasting System

Abstract. Operational real time flood forecasting systems generally require a hydrological model to run in real time as well as a series of hydro-informatics tools to transform the flood forecast into relatively simple and clear messages to the decision makers involved in flood defense. The scope of this paper is to set forth the possibility of providing flood warnings at given river sections based on the direct comparison of the quantitative precipitation forecast with critical rainfall threshold values, without the need of an on-line real time forecasting system. This approach leads to an extremely simplified alert system to be used by non technical stakeholders and could also be used to supplement the traditional flood forecasting systems in case of system failures. The critical rainfall threshold values, incorporating the soil moisture initial conditions, result from statistical analyzes using long hydrological time series combined with a Bayesian utility function minimization. In the paper, results of an application of the proposed methodology to the Sieve river, a tributary of the Arno river in Italy, are given to exemplify its practical applicability.

Sign in / Sign up

Export Citation Format

Share Document