Study on the Suitability of Rainfall Intensity Formula and Intensity Duration Frequency Curve (IDF) in the Campus Area of Universitas Brawijaya, Malang

2021 ◽  
Vol 26 (2) ◽  
pp. 247-257
Author(s):  
Donny Harisuseno

Rainfall intensity known as an essential variable in rainfall-runoff transformation. Flood events occurred in 2017 at Brawijaya University campus caused by high intensity and landuse change in campus's internal and external environment. The study aims to examine performance of several empirical  formulas  in estimating rainfall intensity, investigating characteristic of each empirical formula’s contant due to varying return period (Tr), and determining appropriate Intensity Duration Frequency (IDF) curve. The formula of Sherman, Talbot, and Ishiguro was employed to obtain empirical intensity, while intensity on varying return period was calculated using Log Pearson Type III. The proposed rainfall intensity formula was selected through comparison between empirical intensity with those from observation according to criteria of relative error (KR), Nash Sutcliffe Efficiency (NSE), and Peak Weight Root Mean Square Error (PWRMSE). The Sherman formula showed best performance in estimating rainfall intensity as indicated by low value of KR and PWRMSE, followed by NSE close to one. The constant of empirical formula “a” was directly proportional with increasing of Tr; conversely, constant “b” and “n” were inverse with Tr. The validation result of Sherman formula demonstrated that the formula showed good reliability, thus recommended to estimate intensity and IDF curve in the study area.

Author(s):  
Nizeyimana Jean Claude ◽  
Shanshan Lin ◽  
Ndayisenga Fabrice ◽  
Gratien Twagirayezu ◽  
Junaid Khan ◽  
...  

Due to the increase in the emission of greenhouse gases, the hydrologic cycle is being altered on the daily basis. This has affected the variations in relations of intensity, duration, and frequency of rainfall events. Intensity Duration Frequency (IDF) curves describe the relationship between rainfall intensity, rainfall duration and return period. IDF curves are one of the most often applied implements in water resource engineering, in areas such as for operating, planning and designing of water resource projects, or for numerous engineering projects aimed at controlling floods. In particular, IDF curves for precipitation answer problems of improper drainage systems or conditions and extreme characters of precipitation which are the main cause of floods in Nyabugogo catchment. This study aims to establish Rainfall IDF empirical equations, curves and hydrological discharge (predicted peak rate of runoff (Qlogy)) equations for eight Districts that will be used for designing an appropriate and sustainable hydraulic structures for controlling flood to reduce potential loss of human and aquatic life, degradation of water, air and soil quality and property damage and economic lessen caused by flood in Nyabugogo catchment. However Goodness of Fit tests revealed that Gumbel’s Extreme-Value Distribution method appears to have the most appropriate fit compared with Pearson type III distribution for validating the Intensity-Duration-Frequency curves and equations through the use of daily annual for each meteorological station. The findings of the study show that the intensity of rainfall increases with a decrease in rainfall duration. Additionally, a rainfall of every known duration will have a higher intensity if its return period is high, while the predicted peak rate of runoff (Qlogy) increases also with an increase in the intensity of rainfall.


2016 ◽  
Author(s):  
Reza Ghazavi ◽  
Ali Moafi Rabori ◽  
Mohsen Ahadnejad Reveshty

Abstract. Estimate design storm based on rainfall intensity–duration–frequency (IDF) curves is an important parameter for hydrologic planning of urban areas. The main aim of this study was to estimate rainfall intensities of Zanjan city watershed based on overall relationship of rainfall IDF curves and appropriate model of hourly rainfall estimation (Sherman method, Ghahreman and Abkhezr method). Hydrologic and hydraulic impacts of rainfall IDF curves change in flood properties was evaluated via Stormwater Management Model (SWMM). The accuracy of model simulations was confirmed based on the results of calibration. Design hyetographs in different return periods show that estimated rainfall depth via Sherman method are greater than other method except for 2-year return period. According to Ghahreman and Abkhezr method, decrease of runoff peak was 30, 39, 41 and 42 percent for 5-10-20 and 50-year return periods respectively, while runoff peak for 2-year return period was increased by 20 percent.


Author(s):  
Ify L. Nwaogazie ◽  
M. G. Sam ◽  
A. O. David

The design of structures for flood mitigation depends on the adequate estimation of rainfall intensity over a given catchment which is achieved by the rainfall intensity duration frequency modelling. In this study, an extensive comparative analyses were carried out on the predictive performance of three PDF – IDF model types, namely: Gumbel Extreme Value Type 1 (GEVT – 1), Log-Pearson Type 3 (LPT – 3) and Normal Distribution (ND) in 14 selected cities in Southern Nigeria. This is to rank the order of best performance. The principle of general model development was adopted in which rainfall intensities at different durations and specified return periods were used as input data set. This is not same as return period specific model that involves rainfall intensities for various durations and a given return period. The predicted rainfall intensity values with the PDF – IDF model types indicate high goodness of fit (R2) and Mean Squared Errors (MSE) ranging from: (a) R2 = 0.875 – 0.992; MSE = 33.17 – 224.6 for GEVT – 1; (b) R2 = 0.849 – 0.990; MSE = 65.34 – 405.5 for LPT – 3 and (c) R2 = 0.839 – 0.992; MSE = 29.23 – 200.2 for ND. The comparative analysis of all the 42 general models (14 locations versus 3 model types) considered showed that the order of best performance is LPT – 3 1st, GEVT - 1 2nd and ND 3rd for each return period (10, 50 and 100 years). The Kruskal Wallis test of significance indicates that no significant difference exists in the predictive performance of the three General models across the board. This may be due to the fact that the fourteen locations of the study area are bordering with the Atlantic Ocean and seems to have similar climatology. These developed General models are recommended for the computation of intensities in the fourteen locations for the design of flood control structures; and the order of preference should be LPT – 3 > GEVT – 1 > ND.


2020 ◽  
Vol 12 (2) ◽  
pp. 83-90
Author(s):  
Agam Sanjaya

ANALISIS DEBIT PUNCAK SUNGAI LUBUK BANYAU KABUPATEN BENGKULU UTARA DENGAN MENGGUNAKANMETODE HIDROGRAF SATUAN SINTETIK Agam Sanjaya I1), Khairul Amri II2), Muhammad Fauzi III3) 1) 2) 3)Jurusan Teknik Sipil, Fakultas Teknik UNIB Jl. W.R. Supratman, Kandang Limun, Kota Bengkulu 38371, Telp. (0736)344087e-mail: [email protected], [email protected] , [email protected] aliran sungai (DAS) Sungai Lubuk banyau merupakan salah satu DAS yang berada di Bengkulu Utara. DAS Sungai Lubuk banyau mengalir dari daerah hulu yang terletak diwilayah Kabupaten Bengkulu utara. Tujuan dari penelitian ini adalah menganalisa debit puncak rencana akibat intensitas curah hujan pada DAS Lubuk Banyau dalam menganalisis hidrologi dengan menggunakan metode Hidograf Satuan Sintetik (HSS) Gama I, HSS Nakayasu dan HSS Snyder. Berdasarkan hasil perhitungan dari penelitian ini distribusi frekuensi terhadap tiga metode curah hujan, yaitu metode ditribusi Gumbel Tipe I, Log Pearson Tipe III dan Log Normal maka metode yang digunakan untuk perhitungan curah hujan rencana pada penelitian ini adalah Metode Gumbel Tipe I dengan periode ulang 2, 5, 10, 25, 50 dan 100 tahun, yaitu 181,164 mm, 275,356 mm, 337,709 mm, 416,518 mm, 474,974 mm dan 532,998 mm. Dari hasil analisis hidrologi pada penelitian diperoleh debit puncak pada DAS Lubuk Banyau untuk periode ulang 100 tahun dengan metode HSS Snyder adalah 1531,111 m3/detik dengan waktu puncak sebesar 5 jam merupakan debit puncak yang paling besar diantara HSS Gama I dan Nakayasu. untuk hasil debit puncak dengan metode HSS Gama I adalah 776,91m3/detik dengan waktu puncak sebesar 4 jam dan HSS Nakayasu 1023,87 dengan waktu puncak 2,46 jam. Maka didapatkan tinggi permukaan air pada DAS Lubuk Banyau yaitu 1,134 m.Kata kunci: hidrograf satuan sintetik, debit puncak, gama I, nakayasu, dan snyderAbstractWatershed Lubuk Banyau is one of the watersheds in North Bengkulu. The Lubuk River watershed flows from the upstream area located in the northern Bengkulu regency. The purpose of this study is to analyze the planned peak discharge due to rainfall intensity in the Lubuk Banyau watershed in analyzing hydrology using the Synthetic Unit Hydrograph (HSS) method of Gama I, HSS Nakayasu and HSS Snyder. Based on the results of calculations from this study the frequency distribution of three rainfall methods, namely the Gumbel Type I distribution method, Pearson Type III Log and Normal Log, the method used for calculating the planned rainfall in this study is the Gumbel Type I method with a return period of 2, 5, 10, 25, 50 and 100 years, namely 181,164 mm, 275,356 mm, 337,709 mm, 416,518 mm, 474,974 mm and 532,998 mm. From the results of the hydrological analysis in the study, the peak discharge in the Lubuk Banyau watershed for a 100-year return period with the Snyder HSS method was 1531,111 m3 / second with a peak time of 5 hours being the largest peak discharge between Gama I and Nakayasu HSS. for the peak discharge using the HSS Gama I method is 776.91m3 / sec with a peak time of 4 hours and Nakayasu HSS of 1023.87 with a peak time of 2.46 hours. Then the water level obtained at the Lubuk Banyau watershed is 1,134 m.Keywords: synthetic unit hydrograph, peak discharge gama I, nakayasu, and snyder.


Hydrology ◽  
2020 ◽  
Vol 7 (4) ◽  
pp. 78
Author(s):  
Ena Gámez-Balmaceda ◽  
Alvaro López-Ramos ◽  
Luisa Martínez-Acosta ◽  
Juan Pablo Medrano-Barboza ◽  
John Freddy Remolina López ◽  
...  

Intensity–Duration–Frequency (IDF) curves describe the relationship between rainfall intensity, rainfall duration, and return period. They are commonly used in the design, planning and operation of hydrologic, hydraulic, and water resource systems. Considering the intense rainfall presence with flooding occurrences, limited data used to develop IDF curves, and importance to improve the IDF design for the Ensenada City in Baja California, this research study aims to investigate the use and combinations of pluviograph and daily records, to assess rain behavior around the city, and select a suitable method that provides the best results of IDF relationship, consequently updating the IDF relationship for the city for return periods of 10, 25, 50, and 100 years. The IDF relationship is determined through frequency analysis of rainfall observations. Also, annual maximum rainfall intensity for several duration and return periods has been analyzed according to the statistical distribution of Gumbel Extreme Value (GEV). Thus, Chen’s method was evaluated based on the depth-duration ratio (R) from the zone, and the development of the IDF relationship for the rain gauges stations was focused on estimating the most suitable (R) ratio; chosen from testing several methods and analyzing the rain in the region from California and Baja California. The determined values of the rain for one hour and return period of 2 years (P12) obtained were compared to the values of some cities in California and Baja California, with a range between 10 and 16.61 mm, and the values of the (R) ratio are in a range between 0.35 and 0.44; this range is close to the (R) ratio of 0.44 for one station in Tijuana, a city 100 km far from Ensenada. The values found here correspond to the rainfall characteristics of the zone; therefore, the method used in this study can be replicated to other semi-arid zones with the same rain characteristics. Finally, it is suggested that these results of the IDF relationship should be incorporated on the Norm of the State of Baja California as the recurrence update requires it upon recommendation. This study is the starting point to other studies that imply the calculation of a peak flow and evaluation of hydraulic structures as an input to help improve flood resilience in the city of Ensenada.


Author(s):  
A. O. David ◽  
Ify L. Nwaogazie ◽  
J. C. Agunwamba

The rainfall Intensity-Duration-Frequency (IDF) relationship is widely used for adequate estimation of rainfall intensity over a particular catchment. A 25 year daily rainfall data were collected from Nigerian Meteorological Agency (NIMET) Abuja for Akure station. Twenty five year annual maximum rainfall amounts with durations of 5, 10, 15, 20, 30, 45, 60, 90, 120, 180, 240, 300 and 420 minutes were extracted and subjected to frequency analysis using the excel solver software wizard. A total of six (6) return period specific and one (1) general IDF models were developed for return periods of 2, 5, 10, 25, 50 and 100 years using Gumbel Extreme Value Type-1 and Log Pearson Type -3 distributions. Anderson Darling goodness of fit test was used to ascertain the best fit probability distribution. The R2 values range from 0.982 to 0.985 for GEVT -1 and 0.978 to 0.989 for Log Pearson type -3 while the Mean Squared Error from 33.56 to 156.50 for GEVT -1 and 43.01 to 150.63 Log Pearson Type III distributions respectively. The probability distribution models are recommended for the prediction of rainfall intensities for Akure metropolis.


1994 ◽  
Vol 29 (1-2) ◽  
pp. 303-310 ◽  
Author(s):  
Kazuyuki Higuchi ◽  
Masahiro Maeda ◽  
Yasuyuki Shintani

The Tokyo Metropolitan Government has planned future flood control for a rainfall intensity of 100 mm/hr, which corresponds to a return period of 70 years, and a runoff coefficient of 0.8. Considering that the realization of this plan requires a long construction period and high construction costs, the decision was made to proceed by stages. In the first stage, the improvement of the facilities will be based on a rainfall intensity of 75 mm/hr (presently 50 mm/hr), corresponding to a return period of 17 years, and a runoff coefficient of 0.8. In the next stage the facilities will be improved to accommodate a rainfall intensity of 100 mm/hr. In the Nakano and Suginami regions, which suffer frequently from flooding, the plan of improvement based on a rainfall intensity of 75 mm/hr is being implemented before other areas. This facility will be used as a storage sewer for the time being. The Wada-Yayoi Trunk Sewer, as a project of this plan, will have a diameter of 8 m and a 50 m earth cover. This trunk sewer will be constructed considering several constraints. To resolve these problems, hydraulic experiments as well as an inventory study have been carried out. A large drop shaft for the trunk sewer is under construction.


Water ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 1943
Author(s):  
Rosario Balbastre-Soldevila ◽  
Rafael García-Bartual ◽  
Ignacio Andrés-Doménech

The two-parameter gamma function (G2P) design storm is a recent methodology used to obtain synthetic hyetographs especially developed for urban hydrology applications. Further analytical developments on the G2P design storm are presented herein, linking the rainfall convectivity n-index with the shape parameter of the design storm. This step can provide a useful basis for future easy-to-handle rainfall inputs in the context of regional urban drainage studies. A practical application is presented herein for the case of Valencia (Spain), based on high-resolution time series of rainfall intensity. The resulting design storm captures certain internal statistics and features observed in the fine-scale rainfall intensity historical records. On the other hand, a direct, simple method is formulated to derivate the design storm from the intensity–duration–frequency (IDF) curves, making use of the analytical relationship with the n-index.


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