Flood Distribution Research Articles

Intra-annual dendrogeomorphic dating and climate linkages of flood events in headwaters of central Europe

Unlike large rivers, floods in headwaters have been poorly documented despite the fact that greater discharges are expected in such areas due to ongoing rainfall intensification. The purpose of this study is to carry out intra-annual dating of past floods combined with analysis of their climate linkages which may point on distribution and origin of floods. To this end, we applied dendrogeomorphic dating of impact scars on riparian vegetation to provide flood chronologies in twelve headwaters of eastern Czechia and determined their seasonal occurrences. Furthermore, we analyzed the precipitation indices and evaluated the flood events using reanalysis of pressure fields and the climate oscillation indices, particularly those representing the North Atlantic, Scandinavian, and East Atlantic/Western Russian patterns. Based on 434 dated trees, we identified 22–31 flood event years in each region over the last 70 years. The most frequent floods occurred from May to July. In addition, in ten event years it was possible to identify multiple flood events: for example May and July–August floods in 2010, 2014, and 2016. The monthly precipitation showed the strongest, but still weak, correlation with indices of Scandinavian climate oscillation during summer months (Rs = 0.23–0.42; p < 0.00), suggesting the influence of a blocking anticyclone over Scandinavia and wet air propagation to central Europe. This finding was also confirmed by the most frequent positions of low-pressure centers located east of the study sites except for the region with western orographic enhancement. In addition, timing shift of extreme precipitation to earlier period was identified at two out of three regions. We conclude that intra-annual dating of floods supported by analyses of climate extremes provides new data from sparsely gauged headwaters, thereby supplementing the information on possible changes in flood occurrences during ongoing climate change.

Multivariate modeling of flood characteristics using Vine copulas

Vine copulas provide a great deal of flexibility in modeling complex dependence structures between the variables. In spite of its importance, very limited attention has been paid in hydrology field. In the present study, multivariate modelling of flood characteristics was performed using traditional Archimedean and Elliptical and Vine copulas. In the first phase, flood characteristics [peak (Q), volume (V) and duration (D)] were computed from daily streamflow of 18 stations located in the Euphrates River Basin, Turkey. Based on various model selection criteria, the gamma and Weibull distributions for Q series, the logistic and generalized extreme value distributions for V series and the logistic, log-logistic and generalized extreme value distributions for D series were mostly found to be the best appropriate univariate models. In the second phase, the considered copulas were evaluated for modeling joint distribution of flood Q–V–D triplets at each station. On evaluating their performance by various copula selection methods, graphical procedures and tail dependence analysis, the Vine copulas have been identified as the most valid models. In last phase, conditional and joint return periods of different flood Q, V and D combinations were estimated and the spatial distribution of the return periods were drawn using Geographic Information Systems tool.

Little Ice Age, Palaeofloods and human adaptation on the Jarama River (Tajo Basin, Central Spain) from documentary proxy data

This research assesses the close relationship between river history and human adaptation by combining the study of the migration of channels on the floodplain, the temporal distribution of floods, and human adaptation to the fluvial environment during the Little Ice Age (LIA) period on the Jarama River section situated between the mouths of two tributaries, the Henares and Manzanares. The methodology consists of the employment of abundant documentary records from the 14th to 19th centuries related to the response of society to hydrological dynamics within changing river patterns. The management and delimitation of land ownership, along with the readjustments and modifications therein, allow the inference of the changes that have taken place in the river throughout history. These changes include meander cut-offs, the abandonment of a channel fragment and aggradation in the alluvial plain, all of them located in different areas within the study area and with different historical timeframes. A relationship exists between changes in fluvial dynamics and the times of the greater abundance of floods. An initial change in the alluvial plain occurred in the Middle Ages as a result of the abandonment of the medieval channel and the creation of a new channel. The second change occurred between the 15th and 17th centuries and affected the properties on the right-hand bank of the river. Since the 18th century, the abandonment of and reduction in meanders and the aggradation at the Manzanares-Jarama mouth have created a new alluvial plain of the river. The different phases of the LIA defined herein coincide with much of the palynological and dendrochronological research conducted in other areas of the southwestern fringe of Europe. From the historical point of view, critical changes appear to be associated with some LIA phases. Furthermore, the progressive transformation of communal lands into public or private property could be promoted by the intense floods recorded since the 15th century. The Maunder and Dalton Minimums occurred together with an increase in the area assigned for agriculture on the alluvial plain; this land use type continued to grow during the 19th and 20th centuries.

Effects of matrix permeability and fracture on production characteristics and residual oil distribution during flue gas flooding in low permeability/tight reservoirs

The effects of matrix permeability and fracture on production characteristics and residual oil distribution of flue gas flooding in low permeability/tight conditions are analyzed systematically by laboratory physical simulation experiments and low-field nuclear magnetic resonance (LFNMR) system. T2 spectra results show that the crude oil is mainly distributed in the corresponding macropores of 100–1000 ms before and after the flue gas injection, and the crude oil in macropores is produced in large quantities after the flue gas injection in both fracture and fracture-free low permeability/tight cores. Additionally, oil production performance indicates that matrix permeability has a remarkable effect in fracture-free low permeability/tight cores. T2 spectra combined with slice scanned images show the migration from the macropores to the medium and fine pores is more obvious in the core with high matrix permeability and the final residual oil distribution is more uniform compared to those of the core with low matrix permeability. Matrix permeability is inversely proportional to the gas channeling point and it has a linear relationships with the gas channeling point in a log-log plot in fracture-free low permeability/tight cores. Besides, fracture can significantly reduce the effect of matrix permeability on oil recovery. The presence of fracture weakens the migration of crude oil in low permeability/tight fracture cores, and the residual oil spreads throughout the core. Fracture plays a dominating role in the gas channeling points for different permeability cores.

Application GIS (Geographic Information System) for multi-hazard mapping in Cisolok Village, Indonesia

Flood, landslide, and Tsunami was a disaster that has highest casualties in Indonesia. Based on BNPB’s data on 2019 flood, landslide, and tsunami cause more than 1000 people died or gone. Cisolok Village is one of many areas in Indonesia that has a potential hazard of that three disasters. Cisolok Village has flat and mountainous land-form from zero until more than 25%. slope gradient. There are two rivers that stream on Cisolok Village’s west and east side. Moreover, Cisolok Village has a beach with cliff type. That’s physical characteristic of Cisolok Village can cause the settlement become a prone area. This research is aim to do multi hazard mapping and also to know distribution of flood, landslide, and tsunami hazard and prone areas in Cisolok village. Variable of hazard in this research are slope, distance from river, landform, and altitude. While the prone’s variable is location of settlement in Cisolok Village. Overlay Method was used to create hazard map and prone map. Spatial analysis was implemented to describe the distribution of flood, landslide, and tsunami hazard and prone areas in Cisolok village. The result show that there are areas with high flood, landslide, and tsunami hazard potential in Cisolok Village. High and very high landslide hazard potential area has the largest area (26.6 Ha) than the others. While, Tsunami prone area with high class has the largest areas (8.10 Ha) than the others. Southeast side of Cisolok Village is the prone area with high class in flood, landslide, and tsunami hazard.

Investigation of Water-Flooding Activity Using Radiotracer Technology in Commercial Core-Flood Set Up

An intervention of radiotracer technology in the EOR program has been initiated using commercial core-flood set up. A commercial type of Berea core is used throughout the experiment. 99mTc is chosen as a radioactive tracer for this experiment, which has a half-life of 6 hours and emits gamma rays’ energy of 0.104MeV. It is a liquid radiotracer with the activity of 10GBq (270mCi), eluted and prepared by Institute Cancer of Malaysia (IKN) before transporting it to the laboratory at Centre of Research in Enhanced Oil Recovery (COREOR), Universiti Teknologi Petronas. The experiment was conducted after 3.5 half-lives. Thus the activity has reduced to approximately (1.48GBq) 40mCi during injection inside the system. The results can be used to assist the reservoir engineer in determining the exact water-tracer breakthrough, localize the location of water-tracer concerning time, and determine the residence time distribution and mean residence time of the core flood where the hydrodynamics of the flow can be predicted. Moreover, the introduction of radiotracer inside the core flood rig can be translated as secondary oil recovery. The idea is to integrate radiotracer technology into the existing commercial core flood set up (FES350) to track the movement of fluid during water-flooding operation. Besides, it can be considered as the first interaction of radiotracer in the enhanced oil recovery application studies in Malaysia.

Urban flood risk assessment and analysis with a 3D visualization method coupling the PP-PSO algorithm and building data

Due to the influence of buildings on the distribution of flood and their economic and social attributes, 3D spatial information such as the size of buildings and the flooded ratio of buildings relative to their height has an increasing impact on urban flood risk. However, existing flood risk assessment methods mainly use data in 2D and analysis methods are mostly 2D. In this study, flood variation processes were analyzed in the form of 3D dynamic visualization by coupling an urban drainage model and a flood simulation model with 3D visualization methods. By further combining with 3D building models, the 3D spatial information of buildings related to flood was obtained. In order to study the influence of 3D information on flood risk and combine with other multi-source heterogeneous data for integrated analysis, a 3D visualization assessment and analysis method for flood risk, coupled with the projection pursuit-particle swarm optimization algorithm (PP–PSO) was established (3DVAAM-PP-PSO). A case study from Chaohu City, China, was used to demonstrate the method. The results showed that the PP-PSO algorithm can process high-dimensional information and obtain the objective weight of each index. The 3D information from the influenced buildings had an impact on the evaluation results, which needed to be considered. Through the 3D visualization analysis, the overall distribution of flood risk and that around the buildings were obtained in multi-perspectives. The flood risk during different rainfall return periods were analyzed intuitively and comparatively. This study furnishes a novel method for flood risk assessment and analysis by making the most of 3D spatial information.

Bivariate flood distribution analysis under parametric copula framework: a case study for Kelantan River basin in Malaysia

Flood is becoming an intensive hydro-climatic issue at the Kelantan River basin in Malaysia. Univariate frequency analysis would be unreliable due to multidimensional behaviour of flood, which often demands multivariate flow exceedance probabilities. The joint distribution analysis of multiple interacting flood characteristics, i.e. flood peak, volume and duration, is very useful for understanding critical hydrologic behaviour at a river basin scale. In this paper, a copula-based methodology is incorporated for multivariate flood frequency analysis for the 50-year annual basis flood characteristics of Kelantan River basin at Guillemard bridge station in Malaysia. Investigation reveals that the Lognormal (2P), Johnson SB-4P and Gamma-3P are selected as marginal distributions for the flood peak flow, volume and duration series. Several bivariate families such as mono-parametric, bi-parametric (i.e. mixed version) and rotated version of Archimedean copulas and also the elliptical copula are introduced to cover a large dependence pattern of flood characteristics. The dependence parameter of bivariate copulas is estimated by the method of moments (MOM) based on the inversion of Kendall’s tau and maximum pseudo-likelihood estimator. To analytically validate and recognize most parsimonious copulas, GOF test and Cramer–von Mises distance statistics (Sn) with the parametric bootstrap method are employed. The Gaussian copula is identified as the most justifiable model for joint modelling of the flood peak–volume and peak–duration combination for MOM-based parameter estimation procedure. Similarly, the Frank copula is selected as the best-fitted structure for modelling peak–duration combination based on MPL estimators, but the MOM estimator recognized Gaussian copula as most suitable for peak–volume pair. Furthermore, the best-fitted copulas are used for obtaining the joint and conditional return periods of the flood characteristics.

Identification and Analysis of Microscale Hydrologic Flood Impacts Using Unmanned Aerial Systems

The need for accurate and spatially detailed hydrologic information is critical due to the microscale influences on the severity and distribution of flooding, and new and/or updated approaches in observations of river systems are required that are in line with the current push towards microscale numerical simulations. In response, the aim of this project is to define and illustrate the hydrologic response of river flooding relative to microscale surface properties by using an unmanned aerial system (UAS) with dedicated imaging, sensor, and communication packages for data collection. As part of a larger project focused on increasing situational awareness during flood events, a fixed-wing UAS was used to overfly areas near Greenwood, MS before and during a flood event in February 2019 to provide high-resolution visible and infrared imagery for analysis of hydrologic features. The imagery obtained from these missions provide direct examples of fine-scale surface features that can alter water level and discharge, such as built structures (i.e., levees and bridges), natural storage features (low-lying agricultural fields), and areas of natural resistance (inundated forests). This type of information is critical in defining where and how to incorporate high-resolution information into hydrologic models and also provides an invaluable dataset for eventual verification of hydrologic simulations through inundation mapping.

Flash flood risk assessment for drainage basins in the Himalayan foreland of Jalpaiguri and Darjeeling Districts, West Bengal

Flash floods pose significant threats to the socio-economic development of the Jalpaiguri and Darjeeling Districts. These districts situated in the piedmont zone of Sikkim–Darjeeling and Bhutanese Himalayas suffer from the flash floods, and those cause tremendous loss of life and property more or less every year. This study assessed flash flood risk of watersheds of the Himalayan foreland of Jalpaiguri and Darjeeling Districts in support of mitigation planning. Different hydro-geomorphological setup controls the magnitude, frequency and distribution of flash flood like topography, geomorphology, geology and climatology of the area under study. Land use/land cover and soils also have an integral relationship with run-off generation in the watersheds. Thus, we adopted holistic approach considering the topographic, hydrological, climatological, geological, soil and land use/land cover factors to assess the relative susceptibility to flash floods of the watersheds of Himalayan foreland of Jalpaiguri and Darjeeling Districts. Jaxa 30m DSM, Landsat8 OLI/TIRS and Sentinel 2A satellite images, digitized drainage network, geological, rainfall, soil and geomorphological map were analysed in GIS environment to infer lithology, land use, hydrological soil type and watershed morphometrics. The morphometric parameters were used to assign the relative susceptibility of the watersheds to flash flood, applying the weighted sum average method. Soil Conservation Service rainfall–runoff model of USDA and synthetic unit hydrograph were used to infer the hydrological response of the basin including curve number, runoff depth, time of concentration, lag time, peak discharge, etc. Final flash flood risk map was achieved by the integration of both the susceptibility maps. Higher weightage was given to the susceptibility map produced from run-off modelling and synthetic hydrograph parameters. The result shows that 63% of basins are fall in the high to very high categories of flash flood risk, 28% under medium and only 9% in the low categories of flash flood risk. Accuracy of the model was assessed using the flood inventory coupled with field diagnosis of past flood damages and available records. The resulting flash flood risk map could be used by the planners to adopt mitigation strategies to reduce the severity of the flash flood hazard.

Combination of flood models with weather research and forecast based on extreme rainfall for hazard mitigations

Semarang city in central java Indonesia has a strategic location as the capital of Central Java Province and developed into the fifth largest metropolitan city in Indonesia. The city of Semarang, which is traversed by the north coast route (pantura) is often flooded during the rainy season. This is because the intensity of rainfall is high and some areas in the city of Semarang are rob areas so that when there is a tide of sea water this area will be flooded. The combination of the Flood model and the weather prediction model will illustrate future conditions. The results showed that the prediction of flood distribution based on rainfall for a period of 10 years. With the flood model the period pattern of rainfall intensity values obtained is processed into a relationship graph between the duration of rain in minutes with the intensity of rain in the return period of 2 years, 5 years, 10 years and 25 years. The rainfall intensity value obtained will then be used to determine the peak discharge value

Integrating Internet media into urban flooding susceptibility assessment: A case study in China

This study demonstrates the value of the public and of media observations (i.e. ‘citizen science’) for the modeling and understanding of the predisposing factors of urban flooding as a contribution to flooding hazard assessment. The 2016 Wuhan flood in the center of China utilized observations of non-scientists' from Internet media to capture the spatial distribution of urban flooding. Various sources in online news, blogs, bbs, and governmental websites were included. Independent flood-related factors such as rainfall, wetlands degradation, elevation, land use and land cover, curvature, slope, and normalized difference vegetation index were integrated into a logistic regression model to produce a susceptibility map. The feasibility and accuracy of this model was evaluated via comparison with official inundation maps and shortcomings of previous drainage system design. The accuracy assessment by receiver operating characteristics curve analysis estimated a success rate of 95.4%. This result shows that the data from mainstream media and public observations provide accurate and comparable information on flood occurrence at the urban scale. The assessment can be used to plan and design preventative drainage strategies for decision-makers. Finally, the limitations of Internet media as a new data resource for flooding risk assessment and future directions are discussed.

Flood mapping using hydraulic modeling and Sentinel-1 image: Case study of Medjerda Basin, northern Tunisia

In northwestern Tunisia, floods are the most widespread natural hazard. Indeed, this problem is posed seriously in the Medjerda basin. In fact, the plain of Jendouba - Bou Salem is the most affected area by this plague. It has the form of a shallows that collects runoff water and promotes flood extent and duration. So the main objective of this study is to determine the extent of the hydraulic hazard through the flood mapping of February 2015 event which has seriously affected the urban and peri-urban landscape of the plain. The hydraulic hazard extent mapping was determined through the HEC-RAS model. It's one of the most popular free hydraulic models developed by the Hydrological Engineers Center of the U.S. Army Corps. The new version (HEC-RAS v-5) is a two dimensional (2D) model based on the resolution of hydraulic Saint Venant which can simulate floodplain inundation, determine the water surface elevation and velocity distribution of floods. It allows modeling flow with permanent and non-permanent free surface by evaluating water flows and heights over the all sections of a river so it allows to integrate hydraulic works (bridge, dam …).The result showed that this flood reached heights of more than six (6) meters in flooded areas. The result from the HEC-RAS model was validated using the Sentinel-1 radar image acquired on February 28th, 2015.The study shows the applicability and the capabilities of the 2D HEC-RAS version for flood studies.

Spatial and temporal distribution and trend in flood and drought disasters in East China

Frequent floods and droughts have brought serious impact on economy, society and living environment in East China. Based on the disaster census data of rainstorm-induced flood (including landslide and mud-rock flow) and drought disasters in 637 counties (districts) in East China, the distribution and change of flood and drought disasters were analyzed. The results indicate that the number of records of flood disaster increased at a rate of 77.4 times per decade from 1984 to 2010, while that of drought disaster had no significant trend in East China as a whole. Population affected by floods and droughts increased at rates of 8.7 million and 3.8 million persons per decade, respectively, and the direct economic losses increased at rates of 12.6 billion and 1.9 billion Chinese Yuan per decade respectively, whereas the affected area and the total failure area of crops caused by floods and droughts showed no clear trends. Spatially, the number of records of floods in the southern parts of East China was higher than that in the northern parts, and Anhui, Jiangxi, Zhejiang and Fujian had more records of affected population, deaths, affected crops, total crop failures and direct economic losses, as well as more affected population and deaths. The affected crop area and total crop failure area by floods were also larger in Anhui, Jiangxi and Jiangsu. Drought disaster had higher number of records of affected population, affected crops, total crop failures and direct economic losses in Anhui, Jiangxi, Zhejiang and Shandong, and also affected more people and larger area of crops, leading to larger area of total crop failures and higher direct economic losses in Anhui, Jiangxi and Shandong. The results can provide reference for disaster risk regionalization and environmental risk assessment in East China.

Flood susceptibility assessment based on a novel random Naïve Bayes method: A comparison between different factor discretization methods

Random Naïve Bayes (RNB) is a machine learning method that uses the Random Forest (RF) structure to optimize Naïve Bayes (NB). It is interesting to see whether RNB could optimize NB and achieve satisfied assessment results like RF in the flood susceptibility assessment study. RNB has rarely been used in study of using machine learning methods to spatially analyze natural disasters, and thus it was selected as the analysis method. Based on the data feasibility, 12 spatial factors that affect the occurrence and spatial distribution of floods were selected. To avoid the influence of subjective equal-interval classification method, natural breaks and quantile method were used to discretize factors with continuous values, respectively. Here, a recently proposed repeatedly random sampling method was adopted to select negative samples for RNB to generate a most accurate classifier (MAC) that was employed to compute the probability of flood occurrence in the study area. Consequently, this paper adopted the integrated framework of GIS and RNB to spatially assess the flood susceptibility using the Wanan County in China as an instance. The results demonstrated that when integrated with the repeatedly random sampling method, the MAC-based flood susceptibility maps corresponding to different factor discretization methods were similar, meaning this framework can effectively avoid the effects caused by different factor discretization methods. Also, to testify the classification performance of RNB, RF and NB were chosen to compare the classification performance with it. The results indicated the classification performance in the order of RF > RNB > NB. This means RNB is able to achieve better classification performance than NB, but it exists limitations when compared with traditional strong classifiers like RF. The findings of this paper proved that RNB is a feasible approach for natural hazard susceptibility assessment.

Spatiotemporal Characteristics and Driving Force Analysis of Flash Floods in Fujian Province

Flash floods are one of the most destructive natural disasters. The comprehensive identification of the spatiotemporal characteristics and driving factors of a flash flood is the basis for the scientific understanding of the formation mechanism and the distribution characteristics of flash floods. In this study, we explored the spatiotemporal patterns of flash floods in Fujian Province from 1951 to 2015. Then, we analyzed the driving forces of flash floods in geomorphic regions with three different grades based on three methods, namely, geographical detector, principal component analysis, and multiple linear regression. Finally, the sensitivity of flash floods to the gross domestic product, village point density, annual maximum one-day precipitation (Rx1day), and annual total precipitation from days &gt; 95th percentile (R95p) was analyzed. The analytical results indicated that (1) The counts of flash floods rose sharply from 1988, and the spatial distribution of flash floods mainly extended from the coastal low mountains, hills, and plain regions of Fujian (IIA2) to the low-middle mountains, hills, and valley regions in the Wuyi mountains (IIA4) from 1951 to 2015. (2) From IIA2 to IIA4, the impact of human activities on flash floods was gradually weakened, while the contribution of precipitation indicators gradually strengthened. (3) The sensitivity analysis results revealed that the hazard factors of flash floods in different periods and regions had significant differences in Fujian Province. Based on the above results, it is necessary to accurately forecast extreme precipitation and improve the economic development model of the IIA2 region.

Management of Flood-Based Farming in Guguf, Northern Ethiopia

Spate irrigation is the source of moisture for crop production in the semi-arid lowlands of Raya Valley. Despite its higher potential to suport rainfed agriculture, management of flood based farming has received less emphasis. Thus, the study attempted to examine the management of floods across the Guguf irrigation schemes. Survey data were collected from 78 households selected using systematic sampling in 2018. Data were analyzed using desriptive statistics, Chi- square and one-way ANOVA. Results showed that the participation of every farmer in the operation and maintenance activities is mandatory to receive flood. The rule of water distribution based on individual farmer‘s contribution helps to mobilize the minimum labor required to run the spate system. Frequent operation and maintenance activities carried out in upstream canals due to erosive flashy floods. The effect of scheme location was significant overall, F (2, 75) = 24.42, p = 0.000, η 2 = .48. Maize planted in Kusra, the lower scheme, has failed during its early growth stage more clarify the situation. Despite the location based flood water distribution among primary canals, distribution within the canal starts first by drawing lottery among the head, middle and tail users. In using the flood, users gradually developed different traditional water rights and distribution rules including the rule for operation and maintenance of the spate system. Instead of the present location based flood distribution that favors to farmers at the head of the spate system, even a small flood can be sufficient if allocated based on crop type and growth stage. Keywords: Guguf, management, flood-based farming, allocation, Northern Ethiopia DOI: 10.7176/JAAS/61-02 Publication date: February 29 th 2020

A Generalized Automated Framework for Urban Runoff Modeling and Its Application at a Citywide Landscape

This research presents a fully automated framework for runoff estimation, applied to Philadelphia, Pennsylvania, a major urban area. Trends in global urbanization are exacerbating stormwater runoff, making it an increasingly critical challenge in urban areas. Understanding the fine-scale spatial distribution of local flooding is difficult due to the complexity of the urban landscape and lack of measured data, but it is critical for urban management and development. A one-meter resolution Digital Elevation Model (DEM) was used in conjunction with a model developed by using ArcGIS Pro software to create urban micro-subbasins. The DEM was manipulated to account for roof drainage and stormwater infrastructure, such as inlets. The generated micro-subbasins paired with 24-h storm data with a 10-year return period taken from the National Resources Conservation Service (NRCS) for the Philadelphia area was used to estimate runoff. One-meter land-cover and land-use data were used to estimate pervious and impervious areas and the runoff coefficients for each subbasin. Peak runoff discharge and runoff depth for each subbasin were then estimated by the rational and modified rational methods and the NRCS method. The inundation depths from the NRCS method and the modified rational method models were compared and used to generate percent agreement, maximum, and average of inundation maps of Philadelphia. The outcome of this research provides a clear picture of the spatial likelihood of experiencing negative effects of excessive precipitation, useful for stormwater management agencies, city managers, and citizen.

Hydrodynamic Modelling of Juwana River Flooding Using HEC-RAS 2D

On the equator, Indonesia had very complex geographical, geological, hydrological conditions. It was also traversed by three large plates namely the Eurasian plate, the Indo-Australian plate, and the Pacific plate. Because of the colliding meeting of the three plates, the territory of Indonesia had a variety of topography ranging from hills, mountains, plateaus, lowlands, and basins. The basin found in the Juwana watershed caused frequent flooding every year due to the overflow of Juwana River. The river passed through Kudus and Pati. In the last ten years there had been 179 floods in Juwana River. This study aimed to examine the discharge and distribution of floods based on the return period of floods 2, 5, 10, 25, 50 and 100 years. The research method used was frequency analysis, snyder synthetic unit hydrograph analysis, and hydrodynamic modelling using HEC-RAS 5.0.6 2D (two dimention) with unsteady flow. The findings indicated that on the return period of floods 2, 5, 10, 25, 50, and 100 years, the discharge and distribution of floods were 1169.2 m3/with the inundated area of 22898.54 Ha, 1401.7 m3/with the inundated area of 25558.51 Ha, 1541 m3/with the inundated area of 26916.42 Ha, 1704.9 m3/with the inundated area of 28411.52 Ha, 1819.9 m3/with the inundated area of 29905.85 Ha, and 1930 m3/with the inundated area of 30785 Ha respectively.

Definición y clasificación de las avenidas torrenciales y su impacto en los Andes colombianos

Las avenidas torrenciales son una de las amenazas de origen hidrometeorológico de mayor capacidad destructiva en términos de vidas humanas y pérdidas económicas, especialmente en ambientes montañosos y tropicales como Colombia. Sin embargo, no existe en nuestro país un consenso con respecto a la clasificación y terminología de eventos tipo flujos que permita caracterizar adecuadamente estos fenómenos. El presente artículo analiza el impacto, distribución espacial y temporal de dichos eventos en Colombia, y describe sus tipologías con base en las clasificaciones de fenómenos tipo flujo que se encuentran en el estado del arte. Se propone una clasificación de eventos tipo avenida torrencial para Colombia que incluye tres tipos de fenómenos: creciente súbita, inundación de escombros y flujo de escombros.Ideas destacadas: artículo de revisión que propone una clasificación para los eventos tipo avenida torrencial en Colombia a través de un estudio del estado del arte en el tema a nivel mundial y, además, un análisis del impacto, distribución espacial y temporal de las avenidas torrenciales en el país.