Trend analysis of hydrometeorological data in Euphrates river Basin

Abstract

The Euphrates is the largest river in Iraq. The relationship between runoff and precipitation in the Euphrates River Basin has changed due to the changing climate and increasing human activities, such as increased water consumption, irrigation projects, and dam construction. This study identified the leading causes of these changes and detected abrupt changes in hydro-climatic variables. Data from 19 weather stations and two hydrological stations between 1981 and 2021 was used to examine the nature of these changes. The four sub-catchments of the river basin were studied using the sequential Mann-Kendall test analysis to identify temporal trends and abrupt changes. An annual trend test for non-parametric trends at the basin scale revealed decreased precipitation and runoff over the past 40 years; the increased temperature has potential evaporation since 1981. The stations that showed a significant decrease in annual runoff were mainly located south of the studied river and were primarily affected by human activity. Regression analysis suggests that the decline in runoff after the abrupt change in 1996 may have been primarily caused by human activity.