Assessment of land use and land cover changes on hydrological responses in the Wadi Soummam watershed, Algeria using the HEC–HMS model

ABSTRACT This study aims to predict land use and land cover (LULC) changes for the years 2030 and 2050 using Markov models, and subsequently assess the impacts of these changes on water resources in the Wadi Soummam watershed, Algeria, employing the HEC–HMS model. The research compares five LULC maps (2005, 2015, 2020, 2030, and 2050) to identify variations over the years. The results indicate a notable increase in urbanization, accompanied by a reduction in agricultural and forested areas, leading to a decline in overall vegetation cover. Forests and grasslands experienced a consistent decrease between 2020 and 2050, while urban areas expanded. These LULC alterations have significant implications for the water resources in the study area. From 2030 to 2050, the average annual water yield witnessed an increase of 38.6 m3/s for the 10-year return period event and 70.8 m3/s for the 100-year return period event. Conversely, peak flows exhibited a decline for various return periods between 2005 and 2015, followed by an increase from 2015 to 2020 due to the impact of LULC changes. For instance, the peak flow for the 10-year return period in 2005 was 1651.1m3/s, which decreased to 1604.5 m3/s in 2015, but rose to 1632.8 m3/s in 2020.