Water Flow and Heat Transport in the Hyporheic Zone of Island Riparian: A Field Experiment and Numerical Simulation

Ren, J.; Zhuang, T.; Wang, D., and Dai, J., 2023. Water flow and heat transport in the hyporheic zone of island riparian: A field experiment and numerical simulation. Journal of Coastal Research, 39(5), 848–861. Charlotte (North Carolina), ISSN 0749-0208. Water-level fluctuation is an important factor affecting the island riparian's surface water–groundwater interaction. An island riparian section in the Yueyang section of Dongting Lake downstream of the Three Gorges Dam was selected as the research object. The dimensional transient analysis method and the numerical simulation method of temperature tracing were used to study the water exchange characteristics of the island riparian hyporheic zone. The accuracy of the flow-heat coupling model is verified by the measured data, and the influence of water-level fluctuation on the dynamic change of water and heat in the island riparian was further analyzed. Four analytical models were compared and analyzed. The results show that the dynamic change process of island riparian temperature can be accurately depicted. The vertical temperature stratification of the island riparian is obvious, and the temperature field distribution of the island riparian is affected by various factors such as water-level change, temperature change, and depth. Compared with the numerical model and the four analytical models, the vertical seepage velocity of the island riparian was calculated by the amplitude method, which conformed to the law of groundwater fluctuation and had little difference. It is found that the time period for river water to recharge the groundwater of the island riparian is much larger than the time period for the recharge of the groundwater of the island riparian; the amount of groundwater recharged by the river is larger than that of the groundwater recharge of the island riparian.