MATHEMATICAL MODELLING OF HYDROLOGICAL PARAMETERS EFFECT ON PROBABLE MAXIMUM PRECIPITATION FOR AL-NAJAF AL-ASHRAF CITY

Abstract

In this research, the main aim is to formulate a mathematical model describe the relationship between annual probable maximum precipitation (PMP) for the city of Najaf and other hydrological variables such as temperature, relative humidity and evaporation rates depending on hydrologic data for the period between 1980 to 2005.
All the calculations of the values of annual probable maximum precipitation were made depending on Hershfield's method, which is depended on the general equation of hydrologic frequency analysis and calculating the frequency factor for a group of data. The model was derived by the help of the program (SPSS 21).
The study demonstrated a relative correlation between the previous independent variables, as a group, and the dependent variable (PMP) in one hand and the correlation between each independent variable with the value of PMP in the other hand. The coefficient of determination (R2) obtained from the statistical analysis for four equations were derived for each case with very suitable values.