An investigation of spatially-temporal hydro-climatic data trends and patterns in the Iraqi Diyala River Basin

Abstract

Abstract Climate variability linked to anthropogenic intervention can be considered the main factor affecting the water cycle and hydrological system. Such factors have been considered as the chief distress for water resources engineers and managers, especially in semi-arid and arid regions. This research investigates the spatiotemporal trends and extent patterns of the hydro-climate variables during the past thirty years, comprising yearly and monthly rainfall, temperature, evapotranspiration, and excess rainfall, to estimate the possible effect of such alterations at a local level. The Diyala River catchment, in the central region of Iraq, has been considered an example area. Accordingly, the Mann–Kendall and Pittet methods and the double mass curve process, were used for analysis of the hydro-climatic variables from 1979 to 2012 in the studied catchment. Outcomes of the study designated that excess rainfall alteration during the rainy and dry periods after 1967 had significant corresponding declining trends at a 0.05 confidence level owing to dam building. Annual runoff variations were primarily caused by an anthropogenic intervention involving dam construction to meet water use requirements for agricultural consumption. The rainfall-runoff relationship in the basin has been altered due to weather inconsistency and increasingly intensified human activities. The sudden alterations in the hydro-climatic variables and the key causing influences of the variations in the considered basin have been investigated. The study's findings would help policymakers and water resource engineers identify the risks and vulnerabilities associated with environmental change.