CLIMATE-HYDROLOGY INTERACTIONS AND THEIR INFLUENCE ON STREAMFLOW VARIABILITY IN CHANGING ENVIRONMENTAL CONDITIONS

Abstract

Climate variability affects hydrological processes and functions through variations in precipitation, groundwater recharge and streamflow regimes, which make water resource management more difficult. This research aimed to study climate-hydrology interactions and impacts on streamflow variations in the Yanglou catchment based on 5479 daily hydrological data from 2004 to 2018. Precipitation, groundwater table depth, calculated groundwater recharge and streamflow were evaluated using descriptive statistics, trend analysis, Mann–Kendall, correlation analysis, Spearman and predictive modeling with multiple linear regression and Random Forest regression models. The results indicated a significant temporal and seasonal hydrological variability and around 92.41% of the observations showed that streamflow was zero. The annual precipitation did not show a statistically significant trend while the recharge of the groundwater decreased and the depth of groundwater table increased. Correlation analysis revealed positive relationship between precipitation and streamflow (ρ = 0.1405), groundwater recharge and streamflow (ρ = 0.1641) and negative between groundwater table depth and streamflow (ρ = −0.2984). The multiple linear regression model obtained an R² of 0.2506 while the RMSE was 1.7362 mm/day. The random forest model had a lower MAE of 0.2163 mm/day. Antecedent precipitation (AP) became the most significant predictor. Results highlight the need for integrated monitoring of both precipitation and groundwater to characterize intermittent streamflow, and to inform catchment management decisions for water resources, but with some limitations in the predictability of streamflow during periods of positive flow.