scholarly journals Hydraulic Planning in Insular Urban Territories: The Case of Madeira Island—São Vicente

Water ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 112
Author(s):  
Sérgio Lousada ◽  
Leonardo Gonçalves ◽  
Alper Atmaca
Keyword(s):  
Return Period ◽  
Drainage Basin ◽  
River Mouth ◽  
Gumbel Distribution ◽  
Roughness Coefficient ◽  
Entire Volume ◽  
Detention Basin ◽  
Severe Flood ◽  
Urban Territories ◽  
Drainage Capacity

This study aims to examine the flood propensity of the main watercourse of São Vicente drainage basin and, if relevant, to propose two methodologies to alleviate the impacts, i.e., detention basin sizing and riverbed roughness coefficient adjustment. Geomorphological data were obtained from the watershed characterization process and used through the SIG ArcGIS software for the flood propensity assessment and then for the calculation of the expected peak flow rate for a return period of 100 years through the Gumbel Distribution. Subsequently, the drainage capacity of the river mouth was verified using the Manning-Strickler equation, in order to establish whether the river mouth of the watershed has the capacity to drain the entire volume of rainwater in a severe flood event. In summary, it was possible to conclude that São Vicente’s watershed river mouth is not able to completely drain the rain flow for the established return period. Thus, its drainage capacity was guaranteed by modifying the walls and streambed roughness coefficient and by sizing the detention basin using the Dutch and the Simplified Triangular Hydrograph methods.

Design Inflow Intensity and Design Inflow Profiles for Storm Sewers

1984 ◽  
Vol 16 (8-9) ◽  
pp. 207-218 ◽  
Author(s):  
Frans H M van de Ven
Keyword(s):  
Return Period ◽  
Gumbel Distribution ◽  
Extreme Value Distribution ◽  
Data Series ◽  
Design Discharge ◽  
Common Location ◽  
Housing Area ◽  
Parking Lot ◽  
Box Cox Transformation ◽  
Frequency Curves

Twelve year records of rainfall and of sewer inflow data in a housing area and in a parking lot in Lelystad were available. These data series contained 5-minute depths of rainfall and sewer inflow. Depth-duration-frequency curves were calculated from the monthly extremes, using Box-Cox transformation and a Gumbel distribution. The differences between the curves for rainfall and for inflow are explained by inertia and rainfall losses. These differences are the reason to use inflow as a sewer design parameter. Forthe choice of the design discharge (or inflow) intensity the curves are not well suited. Storage-design,discharge-frequency curves proved to be better interprétable. The selected design discharge is 4 or 5 m3/s/km2. For non-steady flow calculations in sewer systems an inflow profile has to be provided. The prof ileshould be peaked. The most common location of the peak lies between 20 and 50% of the event duration. The return period of the profile has to be known. A bivariate extreme value distribution is used to estimate this return period. From these distributions synthetic inflow profiles could be calculated.

scholarly journals Application of Frequency Analysis on Peak River Discharge toward the Cumulative Floatable Litter Load at Log Boom Sungai Batu

2019 ◽  
Vol 266 ◽  
pp. 02002
Author(s):  
Nur Khaliesah Abdul Malik ◽  
Nor Rohaizah Jamil ◽  
Latifah Abd Manaf ◽  
Mohd Hafiz Rosli ◽  
Zulfa Hanan Ash’aari ◽  
...  
Keyword(s):  
Frequency Analysis ◽  
Return Period ◽  
River Discharge ◽  
Linear Regression Analysis ◽  
Gumbel Distribution ◽  
Environmental Issues ◽  
Decision Making Process ◽  
Rapid Urbanization ◽  
Distribution Method ◽  
Period 2

The accumulation of floatable litter in the river is mainly influenced by the increasing number of human population, rapid urbanization and development which indirectly lead to the changes of hydrological processes in river discharge, decreasing the water quality and aesthetical value of the river. The main objective of this paper is to determine the cumulative floatable litter load captured at the log boom during the extreme events by using the Gumbel distribution method for frequency analysis in river discharge of Sungai Batu. The annual maximum river discharge for a period of 35 years (1982 to 2016) was used in Gumbel distribution method to obtain the discharge for different return period (2, 5, 10, 25, 50, 100, and 200). The result shows that the estimated discharge (103.17 m³/s) can estimate the cumulative floatable litter load (53267.27 kg/day) at 50 years return period. The R2 value obtained from non – linear regression analysis is 0.9986 indicate that Gumbel distribution is suitable to predict the expected discharge of the river. This study is very crucial for the related agencies in highlighting this environmental issues for their future references which can be used as a guidelines during the decision making process in making better improvement.

scholarly journals Do small and large floods have the same drivers of change? A regional attribution analysis in Europe

2020 ◽  
Author(s):  
Miriam Bertola ◽  
Alberto Viglione ◽  
Sergiy Vorogushyn ◽  
David Lun ◽  
Bruno Merz ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Return Period ◽  
Extreme Precipitation ◽  
Gumbel Distribution ◽  
Secondary Importance ◽  
Antecedent Soil Moisture ◽  
Covariate Data ◽  
Study Results ◽  
Flood Quantiles ◽  
Flood Peaks

Abstract. Recent studies have shown evidence of increasing and decreasing trends in mean annual floods and flood quantiles across Europe. Studies attributing observed changes in flood peaks to their drivers have mostly focused on mean annual floods. This paper proposes a new framework for attributing flood changes to potential drivers, as a function of return period (T), in a regional context. We assume flood peaks to follow a non-stationary regional Gumbel distribution, where the median flood and the 100-year growth factor are used as parameters. They are allowed to vary in time and between catchments as a function of the drivers quantified by covariates. The elasticities of floods with respect to the drivers and the contributions of the drivers to flood changes are estimated by Bayesian inference. The prior distributions of the elasticities of flood quantiles to the drivers are estimated by hydrological reasoning and from the literature. The attribution model is applied to European flood and covariate data and aims at attributing the observed flood trend patterns to specific drivers for different return periods. We analyse flood discharge records from 2370 hydrometric stations in Europe over the period 1960–2010. Extreme precipitation, antecedent soil moisture and snowmelt are the potential drivers of flood change considered in this study. Results show that, in northwestern Europe, extreme precipitation mainly contributes to changes in both the median (q2) and 100-year flood (q100), while the contributions of antecedent soil moisture are of secondary importance. In southern Europe, both antecedent soil moisture and extreme precipitation contribute to flood changes, and their relative importance depends on the return period. Antecedent soil moisture is the main contributor to changes in q2, while the contributions of the two drivers to changes in larger floods (T > 10 years) are comparable. In eastern Europe, snowmelt drives changes in both q2 and q100.

Isostasy amplifies relative sea-level change on continental-scale deltas

2021 ◽  
Author(s):  
Sara Morón ◽  
Mike Blum ◽  
Tristan Salles ◽  
Bruce Frederick ◽  
Rebecca Farrington ◽  
...  
Keyword(s):  
Sea Level ◽  
Drainage Basin ◽  
Sediment Accumulation ◽  
River Mouth ◽  
Feedback Mechanism ◽  
Landscape Dynamics ◽  
Passive Margin ◽  
Sea Level Changes ◽  
Isostatic Compensation ◽  
Continental Scale

<p>The nature and contribution of flexural isostatic compensation to subsidence and uplift of passive margin deltas remains poorly understood. We performed a series of simulations to investigate flexural isostatic responses to high frequency fluctuations in water and sediment load associated with climatically-driven sea-level changes. We use a parallel basin and landscape dynamics model, BADLANDS, (an acronym for BAsin anD LANdscape DynamicS) that combines erosion, sedimentation, and diffusion with flexure, where the isostatic compensation of the load is computed by flexural compensation. We model a large drainage basin that discharges to a continental margin to generate a deltaic depocenter, then prescribe synthetic and climatic-driven sea-level curves of different frequencies to assess flexural response. Results show that flexural isostatic adjustments are bidirectional over 100-1000 kyr time-scales and mirror the magnitude, frequency, and direction of sea-level fluctuations, and that isostatic adjustments play an important role in driving along-strike and cross-shelf river-mouth migration and sediment accumulation. Our findings demonstrate that climate-forced sea-level changes set up a feedback mechanism that results in self-sustaining creation of accommodation into which sediment is deposited and plays a major role in delta morphology and stratigraphic architecture.</p>

scholarly journals INFRAGRAVITY PERIOD OSCILLATIONS IN A CHANNEL HARBOR NEAR A RIVER MOUTH

2018 ◽  
pp. 8 ◽  
Author(s):  
Florian Bellafont ◽  
Denis Morichon ◽  
Volker Roeber ◽  
Gaël André ◽  
Stéphane Abadie
Keyword(s):  
Return Period ◽  
Pressure Sensors ◽  
River Mouth ◽  
Type Model ◽  
Storm Event ◽  
Mooring Lines ◽  
Long Period ◽  
One Year ◽  
Free Propagation ◽  
Resonance Oscillations

Port of Bayonne, located in SW France, is a channel harbor situated near the river mouth of the Adour. Long-period oscillations have repeatedly caused snapping of mooring lines of berthed ships and have led to wave resonances in an adjacent marina (seiche). To investigate mechanisms for generation of theses oscillations, a field campaign was carried out during a one-year return-period storm (Hs = 6 m and Tp = 15 s): four pressure sensors were deployed inside the port. To complement the data and to better understand the governing processes that lead to the wave transformations in Port of Bayonne, the storm event was computed with the Boussinesq-type model, BOSZ. The data confirm the model results, which show generation of long infragravity (IG) waves by the incident swell around the harbor entrance and free propagation of these waves without amplification over far distances inside Port of Bayonne. Excited by these long waves, resonance oscillations are only noticeable in a small enclosed marina. Though the IG-waves are not causing substantial changes to the water level along the harbor channel, they are suspected to excite the ships’ eigen modes, which consequently results in mooring problems.

scholarly journals Extreme values of ET0 at Piracicaba, Brazil, for designing irrigation systems

2021 ◽  
Vol 25 (10) ◽  
pp. 677-683
Author(s):  
Verônica G. M. L. de Melo ◽  
José A. Frizzone ◽  
Leonardo L. de Melo ◽  
Antonio P. de Camargo
Keyword(s):  
High Risk ◽  
Return Period ◽  
Extreme Values ◽  
Irrigation System ◽  
Gumbel Distribution ◽  
System Capacity ◽  
Irrigation Systems ◽  
Risk Of Failure ◽  
Irrigation Interval ◽  
Daily Data

ABSTRACT Irrigation system capacity is typically defined by analyzing probabilities of non-exceedance of evapotranspiration. The use of mean monthly values of ET0 may lead to underestimation of the required capacity, whereas use of maximum daily values may result in overestimation of required capacity. This study had the following objectives: (1) to analyze a 30-year series of daily ET0 data from Piracicaba, SP, Brazil, to evaluate the suitability of the Gumbel distribution for estimating the maximum values of ET0 organized in periods of up to 30 days; (2) to determine probable maximum values and to select ET0 values considering the irrigation interval and the risk of failure in terms of irrigation system capacity. Daily data from 1990 to 2019 were used to calculate ET0 using the Penman-Monteith model. The Gumbel distribution fitted to the data and was suitable for characterizing the frequency distribution of the maximum ET0. The probable ET0 for designing irrigation systems can then be estimated based on the expected lifespan, irrigation interval, and return period of ET0 maximum values. The higher the anticipated irrigation system lifespan, the higher the return period needed to attain a low risk of failure. Using the average of maximum ET0 values alone leads to underestimation of system capacity and a high risk of failure in terms of irrigation system capacity.

scholarly journals ANALISIS BANJIR DAN TINGGI MUKA AIR PADA RUAS SUNGAI CILIWUNG STA 7+646 s/d STA 15+049

2018 ◽  
Vol 7 (1) ◽  
pp. 43-49
Author(s):  
Redaksi Tim Jurnal
Keyword(s):  
Frequency Analysis ◽  
Return Period ◽  
Synthetic Data ◽  
Gumbel Distribution ◽  
Peak Discharge ◽  
Design Flood ◽  
Distribution Method ◽  
Flood Peak ◽  
Method Of Calculation ◽  
Flood Discharge

The problem of flooding in DKI Jakarta is considered normal because almost every year can hit the city of Jakarta especially during the rainy season. In DKI Jakarta itself there are several rivers, one of which is Ciliwung River which is the most influential river in DKI Jakarta which often cause flood every year. The purpose of this research is to know the location of flood / river flood that occurs in the segments along Ciliwung River STA 7 + 646 s / d STA 15 + 049. Data processing begins with the calculation of average rainfall, frequency analysis, and then hour-time rain distribution. Method of calculation of flood discharge using the synthetic unit of Nakayasu and Gama I synthetic data. Rainfall data using 2 observation stations for 3 years rain (2014-2016). In the frequency analysis used Gumbel distribution berdasrkan test results suitability data Smirnov- Kolmogorov and Chi-Square. The result of flood peak discharge design with HSS Nakayasu on return period Q5 = 687,80 m3 / dt, Q10 = 743,21 m3 / dt, Q20 = 796,36 m3 / s, Q50 = 865,15 m3 / dt, Q100 = 916,71 m3 / s, while flood peak discharge design with HSS Gama I on return period Q5 = 347,03 m3 / s, Q10 = 372,12 m3 / s, Q20 = 396,20 m3 / s, Q50 = 427, 36 m3 / s, Q100 = 450,71 m3 / s. The design flood discharge value approaching the measured debit value is HSS Nakayasu. Steps continued using HEC-RAS 4.1.0 software to determine the capacity of river catchment by using Nakayasu discharge. After analyzing using the software, most stationing of the Ciliwung River at STA 7 + 646 to STA 15 + 049 can not accommodate the planned discharge during the 20th anniversary period, hence the need for river improvements in the form of river normalization and elevation of dikes.

scholarly journals Using the UKCP09 probabilistic scenarios to model the amplified impact of climate change on drainage basin sediment yield

2012 ◽  
Vol 16 (11) ◽  
pp. 4401-4416 ◽  
Author(s):  
T. J. Coulthard ◽  
J. Ramirez ◽  
H. J. Fowler ◽  
V. Glenis
Keyword(s):  
Climate Change ◽  
Return Period ◽  
Extreme Events ◽  
Sediment Yield ◽  
Drainage Basin ◽  
Climate Change Scenarios ◽  
Hourly Rainfall ◽  
Baseline Values ◽  
The Impact ◽  
Emissions Scenario

Abstract. Precipitation intensities and the frequency of extreme events are projected to increase under climate change. These rainfall changes will lead to increases in the magnitude and frequency of flood events that will, in turn, affect patterns of erosion and deposition within river basins. These geomorphic changes to river systems may affect flood conveyance, infrastructure resilience, channel pattern, and habitat status as well as sediment, nutrient and carbon fluxes. Previous research modelling climatic influences on geomorphic changes has been limited by how climate variability and change are represented by downscaling from global or regional climate models. Furthermore, the non-linearity of the climatic, hydrological and geomorphic systems involved generate large uncertainties at each stage of the modelling process creating an uncertainty "cascade". This study integrates state-of-the-art approaches from the climate change and geomorphic communities to address these issues in a probabilistic modelling study of the Swale catchment, UK. The UKCP09 weather generator is used to simulate hourly rainfall for the baseline and climate change scenarios up to 2099, and used to drive the CAESAR landscape evolution model to simulate geomorphic change. Results show that winter rainfall is projected to increase, with larger increases at the extremes. The impact of the increasing rainfall is amplified through the translation into catchment runoff and in turn sediment yield with a 100% increase in catchment mean sediment yield predicted between the baseline and the 2070–2099 High emissions scenario. Significant increases are shown between all climate change scenarios and baseline values. Analysis of extreme events also shows the amplification effect from rainfall to sediment delivery with even greater amplification associated with higher return period events. Furthermore, for the 2070–2099 High emissions scenario, sediment discharges from 50-yr return period events are predicted to be 5 times larger than baseline values.

Interactions of Morphology Change and Wave and Current Fields around a River Mouth under Severe Flood

2008 ◽  
Vol 55 ◽  
pp. 6-10 ◽  
Author(s):  
Yoshimitsu TAJIMA ◽  
Haijiang LIU ◽  
Yuya SASAKI ◽  
Shinji SATO
Keyword(s):  
River Mouth ◽  
Morphology Change ◽  
Severe Flood

scholarly journals Determination of river design discharge (Tar River case study)

2020 ◽  
Author(s):  
Mohammad Sharifi ◽  
Mohammad Reza Majdzadeh Tabatabai ◽  
Seyed Hossein Ghoreishi Najafabadi
Keyword(s):  
Flood Control ◽  
Gumbel Distribution ◽  
Roughness Coefficient ◽  
Financial Loss ◽  
Control Structures ◽  
Sediment Rating Curve ◽  
Effective Discharge ◽  
Design Discharge ◽  
Manning Roughness

Abstract Rivers are usually exposed to floods that cause significant human and financial loss, for which structures are considered in the rivers for preventing floods and reducing damage. In this way, it is necessary to acquire design discharge for building these structures. The case study was conducted on the Tar River of Ghazi Station in Tehran Province, which originates from 1 km west of Tar Lake in 13 km east of Damavand. The Tar River is one of the tributaries of Damavand River. In this study, the cross section of the river was first measured through surveying and existing maps. The design discharge of flood control structures was designed using the methods described in this study. Moreover, the stage-discharge table was used to obtain the Manning roughness coefficient. The effective discharge was calculated using the sediment rating curve and sediment frequency histogram, while the bankfull discharge was derived from the return period of 17 years discharge record and fitting of Gumbel distribution to the data. The results indicated that the average of dominant, effective, and bankfull discharges could be the appropriate design discharge for the river, as their values are significantly close to each other. However, there is no need to use flood control structures in this river, due to the occurrence of medium frequent flood events in the river.

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