Rasyonel Yöntemin Rasyonel Olmayışı ve İyileştirilmesi

Year 2017, Volume: 1 Issue: 1, 6 - 21, 31.01.2017

Zekai Şen

https://doi.org/10.31807/tjwsm.297140

Abstract

Rational Method Irrationality with Rectification

Abstract

Rational method (RM) is the simplest approach for peak discharge calculation, but it has many simplifying and unrealistic assumptions, which cause biased results in many applications. Among the most important drawbacks are its applicability restriction to small areas, but it is also used without much care even for large, flat and horizontal areas, even though drainage basins might have significant slopes and rough topography. In the RM the rainfall intensity is taken as constant during the storm rainfall duration and over the drainage area coverage. In this paper, first the RM irrationalities are explained and then a modified formulation is proposed by reconsidering geomorphologic and rainfall features. Nonlinear relationships, in the forms of double-logarithmic functions, of peak discharge with drainage area and slope are incorporated in the new formulation. Its application is achieved for a set of drainage sub-basins from the Kingdom of Saudi Arabia.

Keywords

Drainage area, peak discharge, rainfall intensity, rational method, slopes

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