Intensity-duration-frequency Curves Research Articles

Application of TRMM in Deriving Intensity-Duration-Frequency Curve in Bandung Area

A rainfall Intensity-Duration-Frequency curve serves vital purposes in urban water management, typically generated using a long historical rainfall record. In most cases, such measurement is often sparse or poorly done. Hence it becomes a significant challenge to derive this curve. However, many studies have demonstrated the use of satellite rainfall measurement to cope with this data shortage. One of them is TRMM 3B42 Daily, which is employed in this study. This paper presents the application of TRMM to derive a better IDF curve in a data-scarce region for urban water management. It takes place in Bandung, where most of the upstream catchment area has limited rainfall records. The result shows that the TRMM-derived IDF curve demonstrates underestimated rainfall intensity compared to the ground measurement one. Consequently, the correction of daily data TRMM is necessary to improve the performance of TRMM-derived IDF. The correction of daily TRMM has statistically improved the performance of IDF. It is exhibited by the decreasing value of RMSE and RE. This analysis was culminated by producing an updated IDF curve using TRMM data from 1998-2019 for Bandung City. There is no significant trend that appears in rainfall intensity from 2016-2019.

A Combination between Synthetic Unit Hydrograph (SCS) and Rational Method in a similar Conditions Water Shed

Studying watershed characteristics and choosing the most applicable methods to determine the amount of access rainfall that ran off is very important in many engineering applications, especially hydrology applications. That is to know the more suitable methods for protection against floods and to maximize benefits from the excess water. This study aims to establish a relation between the rational method and the SCS method. A subbasin in Wadi Dahab in Sinai, Egypt is investigated as a study area. To achieve the study aims, HEC-WMS software is chosen, which can analyze a watershed by using DEM and delineating basin. It calculates also important watershed parameters like area, runoff distances, and slope. The rainfall data is compiled and arranged. A statical analysis is executed to obtain the IDF curves. Hyfran-plus software is employed to locate the maximum depths for different return periods. Various values for the time of concentration are studied. It is concluded that the difference between the rational and SCS methods is great for the time of concentration till 2 hours, then it decreases obviously from 2 till 6 hours. Also, it is concluded that the difference between the two methods is bigger for the small return periods of 2 and 5 years for all values of the time of concentration. Employing the obtained equations, the peak runoff for one of the two methods (the rational and SCS methods) can be calculated knowing the time of concentration and the peak runoff for the second method.

DEVELOPMENT OF RAINFALL INTENSITY DURATION FREQUENCY (IDF) CURVES FOR DESIGN OF HYDRAULIC STRUCTURES IN KANO STATE, NIGERIA

Rainfall intensity is an essential parameter in the design of any hydraulic structure. The IDF curves are used to design hydraulic structures such as culverts, bridges, roads, urban drainage systems, and many more. Colonial masters developed the first IDF curve for Kano State based on records of 1938 - 1944 (6 years) followed by Oyenbade (1982), and since then, it has not been reviewed or updated. As a result of changes in rainfall patterns that have taken place over time and the climate change, the Oyenbade IDF curves might no longer be suitable for hydraulics design in Kano State. Therefore, this research aims to develop the new IDF curves and establish empirical equations of rainfall intensity that can be used for safe and economic hydraulics design in Kano State. India Meteorological Department (IMD) reduction formula was used to disaggregate maximum daily rainfall of Kano gauge station into the rainfall of shorter durations. Lognormal probability distribution was found to fit best the data set of all the durations using Easyfit 5.0 software and estimate rainfall intensities for 2, 5, 10, 25, 50, and 100 years return periods. It was found out that rainfall intensities increase with the increase in return periods but decreases with an increase in duration. The coefficient of determination ‘R2’ for all return periods indicated a strong relationship in IDF models developed. Hence, the new IDF curves developed should estimate rainfall intensities for hydraulics design in Kano State. The derived IDF models could be used for better results and accuracy.
 Keywords: Probability distributions, IMD reduction formula, return periods, rainfall duration, easy fit software 5.0

Design of edges in contour and half moons from edaphoclimatic parameters, for the endorrheic basin of lagunas de tajzara - ramsar site 1030

The collection of water is proposed from the design of contour borders and half moons, green infrastructure measures, to reduce surface runoff and increase the availability of water for vegetation. The contour and crescent ridges have land ridges with a trapezoidal section, which follow the contour lines, to compartmentalize the slope into smaller hydrological units, the ends of which are located on contour lines. With the data of maximum rainfall every 24 hours and parameters of Gumbel's Law modified, the equations of maximum daily rainfall height (hdT), rainfall height for a duration ´´t´´ (htT), and the Intensity Duration Frequency curve (ItT), for a duration of t <2h. Then considering the values of basic infiltration, vegetation cover, soil type and hydrological condition, the curve numbers were determined for different soil moisture conditions, later the separation length (L) between the Half Moons, and the borders was calculated. in contour, which were designed by means of 10 configurations between diameter and height, for the two infrastructures, being in Copacabana Valle, the greatest separation distance.

Uncertainties in Riverine and Coastal Flood Impacts under Climate Change

Climate change can affect different drivers of flooding in low-lying coastal areas of the world, challenging the design and planning of communities and infrastructure. The concurrent occurrence of multiple flood drivers such as high river flows and extreme sea levels can aggravate such impacts and result in catastrophic damages. In this study, the individual and compound effects of riverine and coastal flooding are investigated at Stephenville Crossing located in the coastal-estuarine region of Newfoundland and Labrador (NL), Canada. The impacts of climate change on flood extents and depths and the uncertainties associated with temporal patterns of storms, intensity–duration–frequency (IDF) projections, spatial resolution, and emission scenarios are assessed. A hydrologic model and a 2D hydraulic model are set up and calibrated to simulate the flood inundation for the historical (1976–2005) as well as the near future (2041–2070) and far future (2071–2100) periods under Representative Concentration Pathways (RCPs) 4.5 and 8.5. Future storm events are generated based on projected IDF curves from convection-permitting Weather Research and Forecasting (WRF) climate model simulations, using SCS, Huff, and alternating block design storm methods. The results are compared with simulations based on projected IDF curves derived from statistically downscaled Global Climate Models (GCMs). Both drivers of flooding are projected to intensify in the future, resulting in higher risks of flooding in the study area. Compound riverine and coastal flooding results in more severe inundation, affecting the communities on the coastline and the estuary area. Results show that the uncertainties associated with storm hyetographs are considerable, which indicate the importance of accurate representation of storm patterns. Further, simulations based on projected WRF-IDF curves show higher risks of flooding compared to the ones associated with GCM-IDFs.

Critical drought intensity-duration-frequency curves based on total probability theorem-coupled frequency analysis

ABSTRACT A methodology using the standardised precipitation index is proposed to develop critical drought intensity-duration-frequency (IDF) curves. We define dry periods within which we recognise droughts of different durations. The most severe drought for each drought duration in each year is called the critical drought. The total probability theorem-coupled frequency analysis is used to determine the best-fit probability distribution function of drought severity, which is then converted to intensity. The generalised extreme value probability distribution function is found to best fit the critical drought severity. The methodology is implemented using monthly precipitation data for a meteorological station in Turkey. The critical drought intensity decreases linearly with increasing drought duration, whereas the return period increases exponentially when the drought becomes more severe. The site-specific IDF curves furnished with an empirical relationship between the intensity and return period allow one to characterise the drought not by an index-based intensity but by its return period. This kind of presentation is physically easier to understand, in particular for stakeholders and decision makers in practice.

Application of Correction Procedures for Some Systematic Measurement Errors to Rainfall Intensity Data of a Rain Gauge in Budapest

The rainfall intensity measurement has a 150 years long history. In the first period of data recordings, the siphoned recording precipitation gauge (pluviographs), or siphoned rainfall writers (SRW), later, the tipping bucket gauges (TBG) were widely used. The systematic errors of these instruments resulted in lower intensity values for long periods. These errors were compensated sporadically. Most of the inaccurate data can be found in the high rainfall intensity range. Some of these data can be found in extracted, aggregated versions only, and the original measurement data is no longer available. These kinds of inherited systematic errors can be corrected. The fixing of siphoning error of SRWs and the supplementary correction of long sampling period data of TBG devices can be a suitable method for the elimination of these issues. In this paper, the application of these two methods is shown in a case study to point out the magnitude and effect of these errors on the IDF curves. The case study on the use of the before-mentioned correction procedures is performed on the rainfall data of the Budapest-Belterület (Budapest City) rainfall station, using data series spanning 105 years. These corrections show that the earlier IDF curves can show 5–10% lower intensities, mainly in the short and low return frequency rainfalls. The result of these kinds of corrections can be significant for the climate change investigations or in the re-evaluation of the elder IDF curves.

A framework for projecting future intensity-duration-frequency (IDF) curves based on CORDEX Southeast Asia multi-model simulations: An application for two cities in Southern Vietnam

To date, no previous studies based on the Coordinated Regional Climate Downscaling Experiment Southeast Asia (CORDEX-SEA), which represents the most comprehensive set of regional climate model simulations in Southeast Asia, have reported the climate change impacts on Intensity-duration-frequency (IDF) curves for designing urban drainage systems. In this study, a framework to project future IDF curves based on a temporal disaggregation of bias-corrected CORDEX-SEA simulations was developed and applied to two cities in Southern Vietnam, i.e. Ho Chi Minh City (HCMC) and Can Tho City (CTC). First, a new bias correction (BC) method, which we call normalized quantile mapping (NQM), was proposed and compared with two other BC methods, quantile mapping (QM) and quantile delta mapping (QDM), to select a suitable BC method for downscaling each dataset of CORDEX-SEA multi-model simulations. A temporal disaggregation model in an artificial neural network (ANN) framework was introduced to obtain future sub-daily rainfall extremes, and the results were compared with the widely used stochastic model, Hyetosminute. Selecting a suitable BC method for each dataset performs better than using one BC method for all datasets in decreasing the ensemble spread by 47.1% in HCMC and 61.4% in CTC. The temporal disaggregation by ANN performs much better than Hyetosminute in durations shorter than or equal to six hours. IDF curves (based on ensemble mean of seven climate models) projected for the far future period (2066–2085) reveal that the rainfall intensity for 25-yr return period is expected to increase by 27.4–32.6% in HCMC and 55.4–72.8% in CTC (depending on the rainfall duration) from those observed for the historical period (1986–2005), while expected to change by −1.1–11.3% for 2-yr return period.Generally, more increase of rainfall intensity for rarer rainfall events (especially for longer durations) urges us to update the existing drainage systems for higher return periods. The framework developed in this study can serve as an important reference for studying climate impacts on the urban drainage systems in other cities located in the same region.

Climate changes impact on stormwater infrastructure design in Tucson Arizona

The stationary-based Intensity-Duration-Frequency (IDF) curves for rainfall provided by the National Oceanic and Atmospheric Administration Atlas 14 (NA14) are the primary data source of stormwater infrastructure design in the United States. Studies have repeatedly signified the non-stationary quality of climatic cycles, which has altered rainfall patterns and increased both frequency and intensity of extreme events, creating a challenge for engineers to adjust design practices under climate change. IDF curves are gradually being updated with climate models to accommodate the adjustment. Yet, many sources of uncertainty, including model selection, can significantly change the final stormwater design. This study updates the IDF curves for the City of Tucson, Arizona, U.S., comparing projections of eight Coupled Model Intercomparison Project Phase 6 (CMIP6) General Circulation Models (GCMs) for the future period (2020–2051). Observed local rainfall data was obtained for the historical period (1970–2001) and used for bias-correcting the models. Utilizing the regional frequency analysis method of NA14, IDF curves were updated for Tucson using the Partial Distribution Series (PDS) as the extreme series. The model selection in this study was based on annual maximum series (AMS) and PDS; however, due to uncertainty associated with GCMs, results for all models were presented, making it clear the extent to which the model selection can affect the design and cost of stormwater systems. Initial results attested to an increase in projected extreme events, their underestimation using stationary assumption, and the need to update IDF curves for Tucson. Moreover, the projected extreme values are greatly affected by model selection and scenarios. An illustrative stormwater culvert design showed that the differences in models’ output could double the design size and considerably increase the cost. The model selection approach utilized in this study can facilitate engineers' and public works decision-making process by filtering out a wide range of projections to fewer preferred options based on GCMs' historical performance over the extreme series as the primary input of IDF curves.

Analysis of Intensity, Duration, Frequency for Groundsill Planning in the Lower Bengawan Solo River Basin

Hydrological analysis is the most important thing in the planning of a water building, including rain. Rainfall characteristics include the intensity of rain (I), length of time of rain (t), depth of rain (d) and Frequency (f). Rainfall intensity can be used to calculate the flood discharge plan using the Rational method. In this study daily rainfall is calculated by analyzing the frequency that starts by determining the average maximum rainfall, then calculating the statistical parameters whose function is to choose the appropriate distribution. So that an appropriate distribution is obtained, namely the Pearson Type III log distribution. From the results of this distribution can calculate the rainfall plan with various times, namely 2,5,10,25 and 50 years. Then the rainfall intensity is calculated using the Mononobe method. The final result of this research is the Intensity Duration Frequency curve. (IDF).

Technical guidelines for future intensity–duration–frequency curve estimation in Canada

ABSTRACT Intensity–duration–frequency (IDF) curves need to be reliable to serve as a relevant tool in preventing or reducing potential damage to society. This often requires accounting for the effect of climate change due to evidence of its effect on extreme precipitation. There is a large number of approaches for IDF curve estimation under climate change in the literature; however, a general framework with practical guidelines for facilitating their application by practitioners is not readily available. The aim of the present study is to provide practical guidelines and recommendations for helping federal and provincial agencies, as well as others who might produce practice guidelines, to develop standardized procedures for the estimation of future IDF curves in Canada that can then be used by practitioners in infrastructure design, management and risk assessment. This is done by gathering and summarizing findings in rainfall frequency analysis from the Canadian FloodNet Research Group, under a practically oriented perspective. Technical recommendations are presented within a methodological framework to facilitate understanding; decision-making procedure-specific flowcharts are provided to facilitate their application. The proposed methodological framework is based on the use of pooled frequency analysis for reasonable estimation of extreme rainfall intensities, and on the estimation of gridded relative changes for IDF updates under climate change following different approaches depending on rain gauge network density. In particular, three methods that do not compete against each other but rather are different methodologies to be applied depending on the case study are proposed: pooled estimation of extreme rainfall in Canada (Method I), gridded relative changes in 24-h extreme rainfall intensities in Canada (Method II) and gridded relative changes in 24-h and sub-daily extreme rainfall intensities in regions of Canada with a relatively high station density (Method III).

IDF (intensity-duration-frequency) curve and unit hydrograph as signature of characteristic changing of Way Kuala Garuntang Watershed

There is direct relation between global warming and precipitation. Air capacity of water increase by 7% to increasing of 1°C of air temperature, causing more water vapor content in the air. This research aims to investigate how IDF Curve and Unit Hydrograph can be used as signature of characteristic changing of Way Kuala Garuntang Watershed. The study area is Way Kuala Garuntang watershed and rainfall data source is from automatic rainfall recorder of Stasiun BMKG Maritim Panjang, ARR Tipping bucket installed at Way Kuala Garuntang watershed, and 4 manual raingauges. From the research can be concluded that IDF Curve can be used as signature of characteristic changing of Way Kuala Garuntang watershed mainly the changing of rainfall intensity in various of return period. Meanwhile, due to average of IUH of 5 flood events in 1 year data serie, and significant differences of Qp between IUH and SUH, the Unit Hydrograph was not suitable as signature of characteristic changing of Way Kuala Garuntang watershed.

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.

Development of Rainfall Intensity-Duration-Frequency (IDF) Curve for Abuja, Nigeria

Urban flooding is a major social and economic problem of any nation. The social implication is attributed to loss of lives and property, unwanted displacement and emotional disturbance attached. While that of economic problem is the cost of mitigation of flood and the aftermath solution. Thus, storm water drainage is part of essential modern city infrastructure. The need for proper analysis and design of drainages and other road water facilities cannot be overemphasized. To achieve this, critical analysis of available rainfall data, which is a key input, is required. A 35 years daily rainfall data were obtained from NIMET, from which the analysis was carried out using frequency method. The output generated are presented in graphical forms and model. Ultimately, an IDF curve generated, depicts Abuja rainfall pattern from which a 3-parameter model equation, I = 37Tr0.2 (t + 0.1)−0.9 was formulated. This is site or location specific. The curve and/or the formulated model can be adopted to determine rainfall intensity of Abuja city if the rainfall duration and return period are predictable.

Impacts of climate change on intensity–duration–frequency curves in the rainiest city (Rize) of Turkey

Changes in precipitation events due to climate change might have significant influences on the characteristics of most hydrological events as well as its own related variables such as intensity, duration, and frequency. Since the intensity–duration–frequency (IDF) curve is an important tool to design infrastructures in water resources management, updating IDF curves under future climate projections nowadays becomes a necessary practice. Therefore, we intended to investigate potential changes in the IDF curves due to climate change using the equidistance quantile matching method in the wettest region of Turkey. We aimed to examine two critical issues: (i) the estimation of changes in IDF curves for three future periods (namely, 2013–2039, 2040–2069, and 2070–2099) and (ii) a comparison analysis between the outcomes based on the two worst-case climate change scenarios (namely, SRES A2 and RCP 8.5) released for the fourth and fifth assessment reports by the IPCC. Our analysis results showed that the outcomes based on SRES A2 revealed an increase in intensities during all the future periods for recurrence intervals under 50 years. According to the outcomes of recurrence interval above 50 years, there is an increase in intensities at the beginning period of the century; however, a decrease in intensities prevails at the ending period of the century. On the contrary, the results based on RCP 8.5 showed that there is a decrease in intensities at the beginning of the century while there is an increase in intensities at the end of the century for all return periods. Our results were discussed according to the indications of the IPCC 5th assessment report. Although conflicting indications were noted between the two worst-case scenarios, our study results may be an inspiration to call a need to update all former design storms based on IDF in any region all over the globe.

Testing a simple formula for calculating approximate intensity-duration-frequency curves

A simple formula for estimating approximate values of return levels for sub-daily rainfall is presented and tested. It was derived from a combination of simple mathematical principles, approximations and fitted to 10 year return levels taken from intensity-duration-frequency (IDF) curves representing 14 sites in Oslo. The formula was subsequently evaluated against IDF curves from independent sites elsewhere in Norway. Since it only needs 24 h rain gauge data as input, it can provide approximate estimates for the IDF curves used to describe sub-daily rainfall return levels. In this respect, it can be considered as means of downscaling with respect to timescale, given an approximate power-law dependency between temporal scales. One clear benefit with this framework is that observational data is far more abundant for 24 h rain gauge records than for sub-daily measurements. Furthermore, it does not assume stationarity, and is well-suited for projecting IDF curves for a future climate.

Determinação da curva de intensidade-duração-frequência do município de Cruzeiro do Sul – Acre

Information on extreme rainfall events associated with predictability and probabilities, especially in intensity-duration-frequency (IDF) curves, are essential for the development of engineering projects aimed at sanitation, drainage and waterproofing of surfaces, which allow to offer more suitable conditions for dimensioning hydraulic and hydrological works and services. However, much of the North Region of the country does not have this information available or updated. Thus, the objective of this study was to develop the IDF equation for the municipality of Cruzeiro do Sul - AC. A 14-year historical series was used, distributed between 1993 and 2011, such data were analyzed by the Gumbel distribution, the same being related, by means of the daily rain breakdown, for return periods comprising 2 to 100 years and rainfall durations of 5 minutes to 24 hours. In the analysis for the construction of the curve, it was observed that the years 1995 and 2002 corresponded to the years with the highest precipitated height indexes, being 111 mm and 103 mm, respectively, however these events had an estimated return time between 3 and 8 years, which does not denote anomalous events. The IDF curve constructed in the study showed good adherence to the observed data, which proves its use in the region.

Updating intensity–duration–frequency curves for urban infrastructure design under a changing environment

AbstractThe intensity and frequency of extreme precipitation have increased in many regions in the past century due to climate change. Many studies have revealed that short‐duration extreme precipitations are likely to become more and more severe in many areas, thus raising a question on whether our urban infrastructures have been designed adequately to cope with these changes. Currently, Intensity–duration–frequency (IDF) curves, which summarize the relationships between the intensity and frequency of extreme precipitation for different durations, are recommended as a criterion for urban infrastructure design and stormwater management. However, climate change is thought to have invalidated the stationary assumption in deriving IDF curves, that is, current IDF curves could misevaluate future extreme precipitation in many cases. Therefore, it is necessary to update the current IDF curves by considering possible changes of extreme precipitation. In this review, we first summarize observed changes in urban short‐duration extreme precipitation and explore the physical mechanisms associated with changes. Then, we introduce two major approaches for updating IDF curves, namely the covariate‐based nonstationary IDF curves and climate‐model‐based IDF curves. Advances in these two updating approaches for IDF curves are the focus of this review. These include the investigation of physically‐based covariates with nonstationary modeling of extreme precipitation; nonstationary precipitation design strategies; and the statistical downscaling and dynamic downscaling methods for projecting future short‐duration precipitation. Finally, we summarize some future research challenges and opportunities on providing reliable projections of future short‐duration extreme precipitation and better characterize the probabilistic behavior of short‐duration extreme precipitation for IDF design.This article is categorized under: Engineering Water > Engineering Water

Construction of IDF curves based on NRCS synthetic rainfall hyetographs and daily rainfall records in arid regions

Construction of intensity-duration-frequency (IDF) curves is crucially important for the design and management of hydro-systems and hydraulic structures. The existence of long-term records of short-duration rainfall is essential for the development of IDF curves. In arid regions, short-duration rainfall records are usually scarce and daily rainfall data are the most commonly available. However, synthetic rainfall hyetographs can afford a simple and suitable tool for extracting short-duration rainfall from daily rainfall data. This study aims to evaluate the ability of the four standard NRCS synthetic rainfall distributions to generate short-duration rainfall data from daily data that might be used to construct IDF curves for an arid region in western Saudi Arabia. The historical intensity and daily rainfall records are collected from 10 recording rainfall stations in Jeddah-Makkah-Taif (JMT) hydrologic region located in western Saudi Arabia. In this study, 2-, 3-, 6-, 12-, and 24-h types I, IA, II, and III NRCS dimensionless rainfall time distributions are used to convert the observed daily rainfall data into shorter duration data. The generated data are used to develop IDF curves and they were compared with those constructed from the available observed rainfall intensity data. Values of the mean absolute percentage error (MAPE) for the used gauge stations range between 5 and 11%. The comparison shows that the NRCS synthetic rainfall distributions are capable to generate short-duration rainfall data that can be used to construct IDF curves for the JMT region. The results also suggest that the 6-h type II NRCS distribution produced IDF curves that are very comparable with those extracted from the observed data. The results also indicate that the 3-h types I and III NRCS distributions have relatively low overall mean values of MAPE (10 to 12%). They can be considered the second-best choice after the 6-h NRCS distribution for developing IDF curves for the study region. This may highlight the applicability of the proposed technique in the JMT region.

Obtención de curvas de intensidad-duración-frecuencia a partir de distribuciones de probabilidad en la cuenca media del río Chone.

En el presente artículo se realizaron las Curvas de Intensidad-Duración-Frecuencia (curva IDF) para la cuenca del río Chone a partir de los datos de intensidad máxima anual para duraciones de 5, 10, 15, 20, 30, 60, 120, 360, 1440 minutos; dichos datos se sometieron a funciones de distribuciones probabilísticas de mejor ajuste, determinado por el mínimo error estándar. Los resultados de esta investigación se compararon con la información proporcionada por INAMHI en sus estudios de lluvias intensas de 1999 y 2015.