טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentMolho Ran
SubjectRainfall Intensity Analysis of the Kineret Watershed
DepartmentDepartment of Agricultural Engineering
Supervisors Mr. Gideon Sinai (Deceased)
Dr. Moshe Getker


Abstract

The goals of this work were to evaluate the rainfall depths and intensities of the Kineret watershed for drainage and flood control design, and to extend the geographic rainfall-depth database developed for Kineret watershed to northern Israel under different time-scales. The research approach was based on rainfall depths and intensities statistical analysis and finding their relationships.

Estimations of maximal yearly and seasonal rainfall intensities probabilities for short periods (10 to 240 minutes) were obtained from the statistical analysis. The analysis was done on data from 25-recorded rain gauges of 20 to 45 years from the year 1944 to 2002 (not all years were measured). Significant differences of rainfall intensities were found between the transition seasons and the central winter season.

The northern Israel region was divided into sub-regions with similar statistical parameters. The sub-region borders were set according to the T-tests of equal averages rainfall intensities. All the rainfall-intensities data of the region were merged to obtain stable and representative estimations.

Finally, the research hypothesis of a connection that exists between the statistical characteristics of the daily-rainfall-depth and the statistical characteristics of the rainfall-intensities for different time periods was tested.

In spite of many findings from Israel and the world, no stable regional connection was found that would allow us to extend the existing rainfall intensity knowledge by the daily or 2-days rainfall-depth data. Therefore, the estimations for the maximal rainfall-intensities at any probability in the area tested were based on the sub-regional division and the merging of the data from those sub-regions.

It was recommended to test the probability estimates of the stations data of the studied location for use of the rainfall intensities in the various models. In addition, it is required to test the probabilities of the proper adjacent station and to test if seasonal partition will result better conditions or maximal yearly values should be taken as usual.

It was suggested to use maximal values of rainfall intensities, due to the high variability of rainfall-intensities in both space and time. Maximal values measured in the recording and daily stations during the last 80 years in the Kineret watershed were given as an envelope curve which expressed the relationship duration-intensity. That envelope curve can be used by design engineers for flood control design in marginal probability. 

It should be noted that no tendency of variation was found among short periods rainfall intensities of rainfall-depths for long periods.