Flood Peak Discharge Research Articles

Linkage of geographically weighted regression with spatial cluster analyses for regionalization of flood peak discharges drivers: Case studies across Iran

Iran has experienced very destructive flooding events with significant socio-economic and environmental consequences over the last years. Identifying and analyzing the driving factors of flood peak discharges (FPDs) with different return periods in the Iran's basins provides a clear picture of the impact degree of different factors on the flood which is crucial for proper management of flood and associated risk mitigation. In this study, the long-term (>30yr) data of 206 continuous-gauging stations across Iran with various hydro-climatic characteristics were selected for the spatial analysis of FPDs drivers with an average recurrence of 2- to 1000-yr. For this aim, the change points, trend analysis, stepwise regressions, global and local Moran's I index, geographically weighted regression (GWR) and two-step cluster analysis were utilized. The results of GWR model demonstrated the drainage area, elevation, heavy precipitation, slope and NDVI are the most FPDs drivers in different frequencies (Q2 to Q1000). The regression coefficients indicated an increase in FPDs with increasing drainage area, heavy precipitation and slope while a decrease in FPDs magnitude obtained with increasing elevation and NDVI for all study basins and different frequencies (Q2 to Q1000). The results also showed that the impact degree of vegetation increases from Q50 to Q1000 and heavy precipitation from Q100 to Q1000. The findings of this study and the proposed methodology provide a replicable research practice that can help the managers and decision-makers to adopt/implement policies for flood risk management.

Performance-based analysis of earth dams: a case study of Hajji Qushan watershed, Iran

Recently, land-use change, as well as climate change through seasonal floods, have caused increasing damage to the Hajji Qushan watershed. Therefore, to reduce the peak discharge of floods, the construction of earth dams is necessary and inevitable. This study aimed to evaluate the effect of embankment structures on the reduction of peak discharge and their effects on the downstream flow regime. For this purpose, to present a favorite rainfall-runoff model and to route the mainstream channel, the HEC–HMS model was utilized. The required data included data from three rain gauge stations and two hydrometric stations. To delineate the boundaries of the watershed, ArcGIS 10.3 (HEC–GeoHMS extension) was implemented. To extract the digital elevation model (DEM), 10-m contour lines were used. The results showed the lack of satisfactory effects of dam construction on the reduction of peak flood discharge. The location of dam construction, reservoir capacity, and watershed area were of the factors that determined the possible reduction of flood risk.

Modeling Flood Peak Discharge Caused by Overtopping Failure of a Landslide Dam

Overtopping failure often occurs in landslide dams, resulting in the formation of strong destructive floods. As an important hydraulic parameter to describe floods, the peak discharge often determines the downstream disaster degree. Based on 67 groups of landslide dam overtopping failure cases all over the world, this paper constructs the calculation model for peak discharge of landslide dam failure. The model considers the influence of dam erodibility, breach shape, dam shape and reservoir capacity on the peak discharge. Finally, the model is compared with the existing models. The results show that the new model has a higher accuracy than the existing models and the simulation accuracy of the two outburst peak discharges of Baige dammed lake in Jinsha River (10 October 2018 and 3 November 2018) is higher (the relative error is 0.73% and 6.68%, respectively), because the model in this study considers more parameters (the breach shape, the landslide dam erodibility) than the existing models. The research results can provide an important reference for formulating accurate and effective disaster prevention and mitigation measures for such disasters.

ASSESSMENT OF THE BEST PROBABILITY DISTRIBUTION METHOD IN RAINFALL FREQUENCY ANALYSIS FOR A TROPICAL REGION

The Intensity-Duration-Frequency (IDF) curve defines the relationship between rainfall intensities at certain durations and with the frequencies. The IDF Curve is extensively used in many applications such as flood modelling and peak discharge estimation. Over the years, the frequent occurrence of flood has become a great challenge in Kelantan river basin. Herein, IDF curves using frequency analyses based on different distributions were developed and compared. The historical rainfall data at eight rainfall stations for the period of 1985-2019 were selected for the assessment purpose. The Gumbel, Normal and Log Pearson Type III distributions were fitted into the annual maximum rainfall series for durations varying from 30 minutes to 24 hours. The goodness of fit tests were then used to evaluate the performances of each frequency distribution. It was found that the Gumbel distribution gave the highest passing rate followed by the Log Pearson Type III and then the Normal distributions. The Gumbel distribution resulted in respective 86% and 75% passing rate since most of the p-values generated by both the K-S and the Mann-Whitney test were greater than 5% of significance level leading to the acceptance of the null hypothesis. Thus, the Gumbel distribution is suggested for the frequency analyses in this study.

Erratum: Kabeja, C., et al. The Impact of Reforestation Induced Land Cover Change (1990–2017) on Flood Peak Discharge Using HEC-HMS Hydrological Model and Satellite Observations: A Study in Two Mountain Basins, China. Water 2020, 12, 1347

In the original article, there was a mistake in Figure 1 as published [...]

Quantitative Prediction of Outburst Flood Hazard of the Zhouqu “8.8” Debris Flow-Barrier Dam in Western China

In recent years, the intensified influences of global climate change and human activities have increased the frequency of large-scale debris flow disasters. As a result, main river channels often become blocked, thus forming a disaster chain of rivers dammed by debris flow followed by outburst flooding. In order to quickly and easily reveal the dynamic process of a debris flow dam breach, and quantitatively predict the outburst flood hazard, this study takes the Zhouqu “8.8” debris flow barrier dam in Western China as an example. Based on a stability assessment, China Institute of Water Resources and Hydropower Research’s Dam Breach Slope (DBS-IWHR), China Institute of Water Resources and Hydropower Research’s Dam Breach (DB-IWHR), and Hydrologic Engineering Center’s River Analysis System (HEC-RAS) were integrated to simulate the development of dam breach, breach flood, and outburst flood evolution, respectively, under different scenarios. The simulated peak discharge flow of the actual spillway was 317.15 m3/s, which was consistent with the actual discharge of 316 m3/s. The results under different scenarios showed that, with the increased inflow of the barrier lake, the erosion rate of the dam increased, the peak discharge of the dam break flood increased, the peak arrival time shortened, and the downstream flooding area increased. These findings could provide scientific support for risk management and emergency decision-making with respect to barrier dam failure.

Estimation of discharges of water flows and debris floods in a small watershed

AbstractFloods in small mountainous watersheds cover a wide spectrum of flow. They can range from clear water flows and hyperconcentrated flows to debris floods and debris flows, and calculation of the peak discharge is crucial for predicting and mitigating such hazards. To determine the optimal approach for discharge estimation, this study compared water flow monitoring hydrographs to investigate the performance of five hydrological models that incorporate different runoff yields and influx calculation methods. Two of the models performed well in simulating the peak discharge, peak time, and total flow volume of the water flood. The ratio (γ) of the monitored debris flood discharge (Qd) to the simulated water flow discharge (Qw) was investigated. Qualitatively, γ initially increased with Qw but then decreased when Qw exceeded a certain threshold, which corresponded to rainfall of 95 and 120 mm in a 6‐ and 24‐h event with a normal distribution of precipitation, respectively. The decrease might be attributable to a threshold of sediment availability being reached, beyond which increased flow rate is not matched by increased sediment input in the large watershed. Uncertainty of hydrological calculation was evaluated by dividing the catchment into sub‐basins and adopting different rainfall time steps as input. The efficiency of using a distributed simulation exhibited marginal improvement potential compared with a lumped simulation. Conversely, the rainfall time step input significantly affected the simulation results by delaying the peak time and decreasing the peak discharge. This research demonstrates the applicability of a discharge estimation method that combines a hydrological water flow simulation and an estimation of γ. The results were verified on the basis of monitored flow densities and videos obtained in two watersheds with areas of 2.34 and 32.4 km2.

Estimated Flood Discharge in Downstream Krueng Meureubo of Pasi Pinang Section West Aceh Regency

The phenomenon of floods in Indonesia has become a routine thing that happens every year, almost all areas that are lowlands often flood when the rainy season arrives. Flooding is caused by high rainfall where the ability of the soil to absorb water decreases along with the rapid development of land that was once a rainwater catchment area, consequently surface runoff becomes high. Pasi Pinang Village can be categorized as a very flood prone village in Meureubo Subdistrict, due to the low condition of this village and directly borders the Meureubo river. Many adverse effects caused by floods and cause losses to the local community. The phenomenon of floods in Indonesia has become a routine thing that happens every year, almost all areas that are lowlands often flood when the rainy season arrives. Flooding is caused by high rainfall where the ability of the soil to absorb water decreases along with the rapid development of land that was once an area. In this case a study on flood discharge analysis needs to be done in order to reduce the incidence of flooding in the village of Pasi Pinang. The method used in this study is the Nakayasu HSS method, aim of this study is to determine the amount of flood discharge that occurred in the Krueng Meureubo River Basin in Pasi Pinang Village. Total hydrograph discharge calculated using the Nakayasu HSS method is the watershed area (A) = 1961.53 km, length of main river (L) = 157.02 km, time delay (tg) = 9.507 hours, duration of rain (Tr) = 7 , 13 hours, the time from the beginning of the flood to the peak of the flood hydrograph (tp) = 15.21 hours, the time of discharge 0.3 times the peak flood discharge (t0.3) = 19.01 hours and the peak flood discharge (Qp) = 23.109 m3 / sec then the total hydrograph discharge obtained by the Nakayasu method is equal to = 2040.26 m3/sec.

Analyses of flood peak discharge in Cimadur river basin, Banten Province, Indonesia

Cimadur river basin is one of the most important catchment areas in Lebak District, Banten Province. For the past few years, the catchment has experienced floods during the rainy season. The big issue of flooding has been recorded recently in December 2019 which has caused damage and negative impacts to the local people and surrounding community. This study aims to analyze the possibility of flood peak discharges in the catchment area of the Cimadur river. The flood discharges are calculated for 2, 5, 10, 25, 50, and 100 years return period based on the daily rainfall data from the year 2011 to 2020. The rainfall and land use data are obtained from PT Saeba Consultant. In this study, the hydrological analyses are including 1) analyses of average annual rainfall using the Thiessen method; 2) analyses of rainfall distribution and estimation of design rainfall by considering three methods involving: Log-Normal, Log Pearson Type III, and Gumbel Type 1; and 3) analyses of flood discharges by adopting Nakayasu Synthetic Hydrograph Unit (SHU). The rainfall distribution analyses show that the Log Pearson Type III provided the best fit. Based on the flood peak discharges analyses, the results show that the flood discharges for the 5, 10, 25, and 50 years return period in the Cimadur river basin are 470.71 m3/s, 560.16 m3/s, 698 m3/s, and 820.4 m3/s, respectively.

Features of the Maximum Water Flows of the Arpa River Under Modern Conditions

The paper discusses the main regularities of the peak flood discharge distribution in modern conditions, using actual data of Hydrometeorology and Monitoring Center SNCO with Ministry of Environment of the Republic of Armenia on the peak flood discharge of the river Arpa.

Flood discharge analysis of Brang Ode River as a disaster mitigation effort in Kalimango Village

Flood is a hydrometeorological disaster that often occurs in West Nusa Tenggara, especially in the Brang Ode River, Kalimango Village, Alas District, Sumbawa Regency. One of the worst floods ever happened was on December 12th, 2016, which caused several villages to be inundated and houses along the river to wash away. This study aims to obtain the peak discharge from the worst flood that has ever occurred. This model is simulated using HEC-RAS 5.0.7 and QGIS for mapping the flood inundation area. Terrain data used DEMNAS. The peak discharge is obtained from the modeling results based on the flood inundation area, validated with the flood map from the DESTANA (disaster resilient village) Community of Kalimango Village. The modeling results showed that the peak flood discharge is 950 m3/s, with the inundation area 150,752.07 m2. The actual peak flood discharge can be smaller or larger than the modeling results. It may be affected by the DEMNAS raster data accuracy.

Magnitude amplification of flash floods caused by large woody in Keze gully in Jiuzhaigou National Park, China

Wood is an important component of flash floods and debris flows in forested mountainous areas. To better understand the characteristics of large wood (LW) movement and its destructive effects on check dams, bridges, and buildings, we conducted field investigations and theoretical calculations on the flash flood process in Keze gully in Jiuzhaigou National Park (China). Based on the gully characteristics and the calculation method, the magnitude amplification ratio of flash flood peak discharge caused by the clogging and breakage processes associated with LW transport reached 2.83 to 3.03 times the mean peak discharge upstream of check dam No. 1. Moreover, the limit analysis and limiting equilibrium state methods were adopted to analyze the additional impact force of LW on the sidewalls of check dams, which resulted in sidewall breaking and sediment block function loss of the check dam. Furthermore, we analyzed the LW transport pattern and formulated a conceptual model of LW transport, including the LW length, channel width, and standing tree spacing. Through this case study, we put forward that the magnitude amplification ratio and the additional impact force of LW should be considered in the design and construction of mitigation engineering projects in forested mountainous areas.

Analysis of urban flood using synthetic unit hydrograph (SUH) and flood mitigation strategies along way Halim River: a case study on Seroja street, Tanjung Senang District

In the urban area, flooding becomes the most common disaster that has not been resolved until today. The utilization of river border area into housing and lack of absorption area becomes the trigger factor of urban flooding, as what is happening around Way Halim River on Seroja street. In this area, floods often happen during the rainy season, with the latest events recorded on January 21st, 2021. Analysis of flood intensities and discharges can be parameters for the decision-making of flood mitigation strategies. This study aims to analyze the flood discharges along Way Halim River, Seroja street by comparing the flood discharges resulting from three analysis methods of Synthetic Unit Hydrograph (SUH) including Gama I SUH, Nakayasu SUH, and Snyder SUH. Finally, suitable flood mitigation strategies were also proposed in this study based on the flood discharges and rain intensities. The results showed that Nakayasu SUH had the highest peak flood discharge than Snyder SUH and Gama I SUH. Based on the results of the investigation of land suitability; and analysis of rainfall intensities and flood discharges, the proposed flood mitigation in Seroja street is by installing biopore infiltration holes along Seroja street for storing water and reducing the risk of flooding in the area.

A study on optimal operation of gate-controlled reservoir system for flood control based on PSO algorithm combined with rearrangement method of partial solution groups

The discharge flow process for flood control of a gate-controlled reservoir is performed by opening and closing the reservoir floodgates. Determining the optimal operation rules of the reservoir system consisting of fully opened floodgates according to time, taking into account the discharge characteristics of the gate-controlled reservoirs during the flood period, was an important demand raised by many reservoir managers. This paper introduces a novel optimization method based on the PSO algorithm combined with the rearrangement method of the particle solution groups to directly determine the optimal operation rules of the reservoir system which consists of the number of fully opened floodgates according to time. When applying the PSO algorithm, unlike previous research that uses the discharge flow process as decision variables, in this paper, the PSO-algorithm which uses the operating plan of floodgates as the decision variables is employed to determine the initial solution for the minimal flood peak discharge in the downstream. This initial solution is modified as a more reliable and realistic optimal operation rule of the reservoir that simultaneously satisfies the maximum flood peak elimination condition and the minimum operation of reservoir floodgates by the newly developed rearrangement method of partial solution groups. To validate the proposed method in this paper, two reservoirs placed in the upstream of Chongchen River and its tributary in the DPR of Korea are selected as a case study. In addition, the PSO algorithm and progressive optimality algorithm (POA) which use the discharge flow process as the decision variables were conducted to compare the performance with the newly proposed method. The validation results show that the method proposed in the paper is superior to the two methods and sufficiently reflects the demand of reservoir managers, which can be effectively applied to the determination of the optimal operating rule of the gate-controlled reservoirs during the flooding period.

ESTIMATION OF ANNUAL RUNOFF AND PEAK FLOW AT NAZANIN CATCHMENT IN ERBIL, KURDISTAN REGION USING DIFFERENT APPROACHES

Runoff is excess rainfall or a portion of rainfall that flows over the watershed. In un-gauged streams, due to lack of data, many methods are used for runoff estimation. In this paper annual runoff and peak flow of Nazanin watershed were estimated at Nazanin Dam location using different methods. Soil Conservation Service (SCS) method, basin relation, (Hydrologic Engineering Center – Hydrologic Modeling System) HEC-HMS and Hydrologic engineering center (HEC-1) models were provided. The Watershed Modeling System (WMS) package was used for watershed delineation and computation of curve number. The area of Nazanin catchment is 72.14 km2, and the composite curve number is 81.3. The results of average annual rainfall estimated using the basin relationship method are more than that obtained from SCS method. The results of peak flood discharge for different return periods using different approaches such as SCS method, HEC-HMS and HEC-1 models are very close. But the results of basin relation are lower than SCS method. From the results of comparison, it was observed that HEC-HMS and HEC-1 models can be used for generation flood hydrograph at ungagged watershed.

Amplification of flood discharge caused by the cascading failure of landslide dams

The cascading failure of multiple landslide dams can trigger a larger peak flood discharge than that caused by a single dam failure. Therefore, for an accurate numerical simulation, it is essential to elucidate the primary factors affecting the peak discharge of the flood caused by a cascading failure, which is the purpose of the current study. First, flume experiments were done on the cascading failure of two landslide dams under different upstream dam heights, downstream dam heights, and initial downstream reservoir water volumes. Then, the experimental results were reproduced using a numerical simulation model representing landslide dam erosion resulting from overtopping flow. Finally, the factors influencing the peak flood discharge caused by the cascading failure were analyzed using the numerical simulation model. Experimental results indicated that the inflow discharge into the downstream dam at the time when the downstream dam height began to rapidly erode was the main factor responsible for a cascading failure generating a larger peak flood discharge than that generated by a single dam failure. Furthermore, the results of a sensitivity analysis suggested that the upstream and downstream dam heights, initial water volume in the reservoir of the downstream dam, upstream and downstream dam crest lengths, and distance between two dams were among the most important factors in predicting the flood discharge caused by the cascading failure of multiple landslide dams.

Quantifying effects of urban land-use patterns on flood regimes for a typical urbanized basin in eastern China

Abstract Artificial adjustment and urbanization are key factors of global change and have significant influences on hydrological processes. This study focuses on the effects of urban land-use patterns on flood regimes in a typical urbanized basin in eastern China. Comprehensive assessments of urban land-use patterns were implemented on three levels: total imperviousness area (TIA) magnitude, landscape configuration and relative location in the basin. Hydrologic Engineering Center's Modeling System (HEC-HMS) was calibrated and validated using four groups of parameters associated with land-use conditions. Fourteen flood events were simulated based on 10 land-use scenarios with different land-use patterns. The results indicate that floods are closely associated with three landscape pattern indicators. First, over the past 20 years, the impermeability rate has increased from 3.92 to 17.48%, with the landscape pattern converted from extension growth form to fill-up growth form after 2003. Second, the average flood peak discharge increased by 80% due to impermeable surfaces expansion, with minor floods more sensitive to the expansion than major floods. Third, the contribution of imperviousness expansion to peak discharge in the inner basin is more remarkable than downstream of the river basin, with the landscape pattern metrics of TIA, arable land and forest land displaying strong correlations with flood characteristics.

Analysis of Annual Peak Flood Discharge Data by Log Pearson Type III Distribution of the River Krishnai of Assam

Analysis of Annual Peak Flood Discharge Data by Log Pearson Type III Distribution of the River Krishnai of Assam

Sensitivity analysis of relationships between hydrograph components and landscapes metrics extracted from digital elevation models with different spatial resolutions

Evaluation of sensitivity of hydrograph components and landscape metrics extracted from various spatial resolutions reveals relationships between landscape metrics and outflow properties with the lowest error. In the present study, 14 Digital Elevation Models (DEMs) with different resolutions derived from a vector and raster-radar source were analyzed to evaluate sensitivity of relationships between simulated hydrograph components and landscape metrics using multiple regression methods in the Galazchai Watershed, West Azerbaijan Province, Iran. To this end, DEM, slope, flow length and direction and time of concentration were developed in the vector and raster scales of 1:25000 and Advanced Land Observing Satellite-1 (ALOS) with different resolutions using ArcGIS 10.5 and ArcHydro software. Accordingly, 588 Direct Runoff Hydrographs (DRHs) were produced and clustered using Clark's Instantaneous Unit Hydrograph (IUH) model. The results showed that the best regression fits for flood volume and peak discharge were determined with Number of Disjunct Core Areas (NDCA) and Patch Density (PD) landscape metrics. Furthermore, the best regression fitted for time to peak and base time were observed with Core Area (CA) and Normalized Landscape Shape Index (NLSI) landscape metrics. In addition, the sensitivity analysis shows that the most sensitive spatial resolutions in modeling relationship between flood volume and peak discharge were determined at 5, 10, 20, and 30 m. The results revealed that hydrograph components in association with landscape metrics had high sensitivity to spatial resolutions, while the relationships between hydrological components and landscape metrics without considering the optimal spatial resolutions resulted in unacceptable results.

Bivariate Hydrologic Risk Assessment of Flood Episodes using the Notation of Failure Probability

Floods are becoming the most severe and challenging hydrologic issue at the Kelantan River basin in Malaysia. Flood episodes are usually thoroughly characterized by flood peak discharge flow, volume and duration series. This study incorporated the copula-based methodology in deriving the joint distribution analysis of the annual flood characteristics and the failure probability for assessing the bivariate hydrologic risk. Both the Archimedean and Gaussian copula family were introduced and tested as possible candidate functions. The copula dependence parameters are estimated using the method-of-moment estimation procedure. The Gaussian copula was recognized as the best-fitted distribution for capturing the dependence structure of the flood peak-volume and peak-duration pairs based on goodness-of-fit test statistics and was further employed to derive the joint return periods. The bivariate hydrologic risks of flood peak flow and volume pair, and flood peak flow and duration pair in different return periods (i.e., 5, 10, 20, 50 and 100 years) were estimated and revealed that the risk statistics incrementally increase in the service lifetime and, at the same instant, incrementally decrease in return periods. In addition, we found that ignoring the mutual dependency can underestimate the failure probabilities where the univariate events produced a lower failure probability than the bivariate events. Similarly, the variations in bivariate hydrologic risk with the changes of flood peak in the different synthetic flood volume and duration series (i.e., 5, 10, 20, 50 and 100 years return periods) under different service lifetimes are demonstrated. Investigation revealed that the value of bivariate hydrologic risk statistics incrementally increases over the project lifetime (i.e., 30, 50, and 100 years) service time, and at the same time, it incrementally decreases in the return period of flood volume and duration. Overall, this study could provide a basis for making an appropriate flood defence plan and long-lasting infrastructure designs. Doi: 10.28991/cej-2020-03091599 Full Text: PDF