Trend analysis of precipitation records using an innovative trend methodology in a semi-arid Mediterranean environment: Cheliff Watershed Case (Northern Algeria)

The description and analysis of rainfall trends is necessary for effective planning, management, and exploitation of water resources. This study investigates the possible trend of precipitation of 28 stations in a semi-arid Mediterranean environment (Northern Algeria) for the period from 1959 to 2019 (60 years), using a recently proposed innovative partial trend methodology. The main advantage of this new method is that it provides qualitative interpretations of trends in the high, medium, and low precipitation ranges in terms of the structure of the time series’ internal trend. An accurate database has been established thanks to the homogeneity of the data quality leading to rather satisfactory results with a precision of the spatial and temporal tendencies, thus establishing maps of regional trends: “high precipitation,” “average precipitation,” and “low precipitation” for the whole study area.