Analysis method of design storm for linear project in central mountainous area of Yunnan Province：case of west Kunming branch of China-Myanmar gas pipeline

The design flood for linear engineering in mountainous area is generally estimated by rainstorm due to the lack of measured data there, so the key point is the design storm calculation. We analyzed the relationship between storm rainfall of different frequency and elevation in valley area, and estimated the storm rainfall of different frequency at the cross-section in valley catchment. The results show that the storm rainfall is closely related to the elevation and catchment area; the empirical formula of the area storm rainfall and elevation possesses high accuracy. The design area storm flood could be calculated by using the empirical formula, in which the point storm rainfall is estimated according to the average elevation of the catchment area, and then the design area storm rainfall is obtained by using point-area reduction coefficient, the result is accord with the characteristics of rainstorm in those mountainous area.