Seasonal variability of hyporheic water exchange of the Weihe River in Shaanxi Province, China

Interactions between surface water and groundwater play a major role in hydrological processes. Understanding the seasonal variations of the water exchange is important to clear drivers of water transferring in a catchment. However, the seasonal variations of water exchange have been limited by the resolution of methods and the experimental problems. In this paper, the Weihe River, in Shaanxi Province, China was chosen, as a case study area to access the seasonal variability of water exchange in the hyporheic zone (HZ). Five testing sites were in the main channel of the river, and seasonal field data were collected from fall 2012 to summer 2014. The temperature profiles and heat convection-diffusion equation were applied to analyze the hyporheic water exchange pattern (the type of movement) and its magnitude, as well as characterizing the seasonal variability of the water exchange features. The results indicate that the patterns and magnitudes of water exchange in the hyporheic zone vary significantly in seasons and test sites. The water exchange general in the fall season (71.5 mm/d) is larger than in other seasons (i.e., spring 54.14 mm/d, summer 56.19 mm/d and winter 23.26 mm/d). This study provides the guidelines for the water resources management in different seasons.