obability that a given rainfall will occur. The parameters f the graph are: in hrs) in mms/hr) y (Return Period) (in yrs) . Formulas for rainfall intensities of long durations, Transactions ty of Civil Engineers, 96, 592-624 R. (1984). A model fitting analysis of daily rainfall data, Journal l Society. Series A(General), 147, 1-34. . (1998). A mathematical framework of studying rainfall uency relationships, Journal of Hydrology, 206, 118-135 plication of Rainfall Frequency Analysis on studying rainfall stics of Chia-Nan plain area in southern Taiwan, Crop, ormatics, 2, 31-38 C. (2006). Statistical Analysis of Indiana rainfall data, Joint rch Program, Final Report intensity is estimated by I = π . π π·+π 1−πΉ(π) οΆParameters a and b are usually similar for a given loca use πΌ = πΎππ π π·+π π . Graph 1 Model estimation Intensity-Duration-Frequency curves 8 10 Parameters of the m Equations of the Model Tr=2 years Tr=5 years Tr=10 years Tr=20 years 6 Rainfall duration (in hrs) ο§ (D) Event duration (in hrs) ο§ (I) Average intensity (in mm/hrs) οΆTable 1: Descriptive statistics of rainfall events. οΆGraph 1: Duration-Intensity scatter plot, inverse propor 1 οΆModel: For every return period ππ = , the relation 12 οΆ Table 2: Parameter e confidence intervals οΆ Return period ππ = 2 years (R=2.1mm) π. ππ π°= π« − π. ππ π.ππ οΆ Return period ππ = 5 years (R=10mm) ππ. ππ π°= π« − π. ππ π.ππ οΆ Return period ππ = 10 years (R=15mm) ππ. ππ π°= π« − π. ππ π.ππ οΆ Return period ππ =20 years (R=25mm) ππ. ππ π°= π« − π. ππ π.ππ Table οΆ Graph 2: IDF curves Graph 2 Exploration of the model appear to be optimal for every chosen return overall correctly identified. ion of model parameters. 0.3534 0.3534 0.3533 0.3533 0.3533 0.353 0.7791 0.779 0.779 0.3531 0.353 0.3531 0.353 R Squared 0.3531 0.7791 0.3532 R Squared 0.3532 R Squared R Squared 0.3532 0.7789 0.7788 0.3529 0.3528 -0.5 0.3529 -0.45 a 0.3528 -0.4 0.7789 0.7788 0.3529 0.3528 0.35 0.4 0.45 b 4 4.5 c 0.7787 -0.4 5 -0.3 a 0.7787 -0.2 0.9885 0.9301 0.9301 0.9301 0.9884 0.9884 0.9299 0.9298 0.9297 -0.6 0.93 0.9299 0.9298 -0.4 a -0.2 0.9297 0.4 0.93 0.9299 0.9298 0.6 b 0.8 0.9297 14 π»π =10 years R Squared 0.9885 R Squared 0.9302 R Squared 0.9302 R Squared 0.9302 0.93 0.7 0.8 b π»π =5 ye π»π =2 years R Squared ere is a chance that estimation methods can imates of the parameters. This can happen when 2 e try to maximize (here π ) gets stuck in a local ined for the selected model. et of parameters is the optimal (the global hed), an analysis using a Monte Carlo type to investigate parameters’ behaviour. ππ , we create 10000 random samples ππ , ππ , ππ , π for different choices of intervals and each time vector with the largest π 2 . repeated 100 times. 0.3534 R Squared s: 0.9883 0.9882 0.9881 16 c 18 0.988 -0.4 Graph 3 0.9883 0.9882 0.9881 -0.2 a 0 0.988 0.7 b π»π =20