ASSESSMENT OF CLIMATE-INDUCED CHANGES IN SURFACE WATER AVAILABILITY AND HYDROLOGICAL DYNAMICS

Abstract

Water resource is a critical part of climate variability which impacts surface water availability and hydrological processes, thereby posing challenges to sustainable water resource management. The goal of this study was to examine long-term changes in climate and how they relate to surface water availability and hydrology for 1,014 catchments in the United States for the period 1980–2023. Retrospective Quantitative approach was used with Secondary hydrometeorological data. Climatic were precipitation, drought indices, temperature and evapotranspiration, and hydrological were mean streamflow, baseflow index and flow variability. Descriptive statistics, temporal trend analysis, Pearson correlation and simple linear regression were used. The results showed a slight positive tendency in the annual precipitation (β = 1.995, p = 0.050), but the maximum 1-day precipitation increased significantly (β = 0.262, p < 0.001). The mean streamflow was positively correlated with annual precipitation (r = 0.867, p < 0.001) accounting for 75.1% of the between-catchment variation in streamflow. Baseflow index was negatively related to temperature and POT, and there were significant catchment differences in discharge and flow variability. These results show that there are strong associations between climatic factors and hydrological parameters, but no climatic causal relationships can be determined. The study emphasises the need for long-term climate monitoring, combined with ongoing discharge monitoring, to enhance surface water assessments, improve drought preparedness and enable sustainable catchment management in a changing climate.