ANALYSIS SOME GAUGING STATIONS IN IRAQ BY USING DISCORDANCY MEASURE AND HETEROGENEITY MEASURE

Abstract

This research deals with the analysis of a group of gauging stations which consists of eleven gauging stations that are used to measure the discharge of Tigris branches within Iraq. They were supposed as a local region which has the same frequency distribution. The discordancy measure was applied in order to determine the deviated station within the region and the heterogeneity measure was applied in order to conclude whether the suggested region is homogeneous or not. If the discordancy measure of each station is compared to the critical value, it will be concluded that there is no deviated station. However, ALTON COBRY station (no. 7) can be shifted to another region so that the whole region can be considered homogenous as the heterogeneity measure is (0.064) which is located within the accepted homogeneous limitations. It was also concluded that there is a certain effect of the number of data for each station on the discordancy measure and sub-sequentially on the heterogeneity decision. Therefore, it was found that the lower the number of data for one station, the higher the number of deviated stations and sub-sequentially the higher the heterogeneity. As a benefit of this research, the analysis which was applied to conclude the heterogeneity measure for the region, so can be found an adequate frequency distribution for a homogenous region and can be used to find a relationship between flood or drought discharges within return period especially for river branches that have no gauging station.