Ingeniero

PAMUKKALE ÜNİVERSİTESİ MÜHENDİSLİK FAKÜLTESİ PAMUKKALE UNIVERSITY ENGINEERING COLLEGE

MÜHENDİSLİK BİLİMLERİ DERGİSİ
JOURNAL OF ENGINEERING SCIENCES

YIL CİLT SAYI SAYFA

: 2007 : 13 : 1 : 75-80

MODELLING OF SHORT DURATION RAINFALL (SDR) INTENSITY EQUATIONS FOR ERZURUM
Serkan ŞENOCAK, Reşat ACAR
Atatürk University, Engineering Faculty, Civil Engineering Department, 25240/Erzurum GelişTarihi : 02.03.2006

ABSTRACT
The scope of this study is to develop a rainfall intensity-duration-frequency (IDF) equation for some return periods at Erzurum rainfall station. The maximum annual rainfall values for 5, 10, 15, 30 and 60 minutes are statistically analyzed for the period 1956 – 2004 by using some statistical distributions such as the Generalized Extreme Values (GEV), Gumbel,Normal, Two-parameter Lognormal, Three-parameter Lognormal, Gamma, Pearson type III and Log-Pearson type III distributions. χ 2 goodness-of-fit test was used to choose the best statistical distribution among all distributions. IDF equation constants and coefficients of correlation (R) for each emprical functions are calculated using nonlinear estimation method for each return periods (T = 2, 5, 10,25, 50, 75 and 100 years). The most suitable IDF equation is observed that
i max (t) = A / ( t + C ) , except for T=100 years, because of the highest coefficients of correlation.
B

Key Words : Statistical distribution function, Rainfall intensity equations.

ERZURUM İÇİN KISA SÜRELİ YAĞIŞ ŞİDDETİ DENKLEMLERİNİN MODELLENMESİ ÖZET
Bu çalışmanın amacı, Erzurum yağış istasyonunda bazı dönüşperiyodları için bir yağış şiddeti-süre-tekerrür (IDF) denklemi geliştirmektir. 5, 10, 15, 30 ve 60 dakikalar için maksimum yıllık yağış değerleri Genelleştirilmiş Ekstrem Değerler (GEV), Gumbel, Normal, iki parametreli Lognormal, üç parametreli Lognormal, Gamma, Pearson tip III ve Log-Pearson tip III dağılımları gibi bazı istatistiksel dağılımlar kullanılarak 1956-2004 aralığı için istatistikselolarak analiz edildi. Bütün dağılımlar arasından en iyi istatistiksel dağılımı seçmek için χ 2 uyum testi kullanıldı. Her amprik fonksiyon için IDF denklem sabitleri ve korelasyon katsayıları (R) bütün dönüş periyodları için (T = 2, 5, 10, 25, 50, 75 ve 100 yıl) lineer olmayan tahmin metodu kullanılarak hesaplandı. En yüksek korelasyon katsayısından dolayı, T = 100 yıl hariç, en uygun IDF denkleminini max (t) = A / ( t + C ) olduğu gözlendi.
B

Anahtar Kelimeler : İstatistiksel dağılım fonksiyonu, Yağış şiddet denklemleri

1. INTRODUCTION
Hydraulic structures are designed to control stormwater volumes and flows need some quantitative

criteria to determine their size. The volume or flow rate which must be stored or conveyed by the system can be related mathematically to theprecipitation for stormwater system design. Two important stormwater parameters, intensity and duration, can be statistically

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Modelling of Short Duration Rainfall (SDR) Intensity Equations For Erzurum, S. Şenocak, R. Acar

related to the frequency of occurence. The resulting graphical representation is the intensity-durationfrequency (IDF) curve. A suitable rainfall IDF relationship is commonlyrequired for planning and design of water resources projects. There has been considerable attention to identify the IDF relationship. Many procedures and formulas, mainly emprical, have been proposed in the literature (Yarnell, 1935; Chow, 1954; Bell, 1969; Chen, 1983; Aron et al., 1987 ). On the other hand, a mathematical approach has been proposed by Burlando and Rosso (1996) and Koutsoyianniset al. (1998). Division of the rainfall duration into three groups (short, intermediate, long durations) leads to regionalization of IDF relationships into different geographical areas for several counties (Froehlich, 1995; Hanson, 1995; Ferro, Froechlich, 1997; GarciaBatual and Schneider, 2001). Record of observed maximum annual rainfall values for durations of 5, 10, 15, 30, and 60 minutes are...