Investigation of groundwater response to overland flow and topography using a coupled MIKE SHE/MIKE 11 modeling system for an arid watershed

SummaryThe distribution of groundwater and dynamic fluctuations in groundwater levels have direct impacts on the eco-environment of arid areas. Investigations of groundwater recharge in arid areas are typically limited by a lack of adequate meteorological and hydrogeological records. This study focuses on groundwater recharge in a seasonally flooded arid area within the Tarim Basin, China, with the aim of analyzing the influence of groundwater and topography on the response characteristics of overland flow. We conducted a simulation using a coupled MIKE SHE/MIKE 11 model over 112 days of the flood season and calculated the average water balance. Based on the properties of the multi-scale recognition of wavelets and the self-comparability of fractals in analyzing the detailed characteristics of groundwater diffusion and fluctuations in groundwater levels, a hybrid fractal–wavelet method was used to explain the recharge response associated with overland flow, distance from midstream, topography, and flooding depth. The results of the model simulations are generally consistent with observed data, indicating that the hybrid fractal–wavelet method is able to recognize the detailed characteristics of the groundwater response. Furthermore, the groundwater levels show a significant relationship with the orientation of the riverway prior to flooding. When flooding occurred, the groundwater levels showed a rapid response to changes in the depth of long-term overland flow. A total of 71.31% of the study area showed a strong correlation between groundwater level and the distance from midstream. The results demonstrate that the relationship exists for fluctuations in groundwater levels of more than 1.4 m. Variations in the height of the water table were significantly influenced by topographic elevation; in contrast, slope and aspect had little effect. In conclusion, the above results indicate that the proposed methodology is applicable for the management of water resources in arid regions. The modeling and hybrid fractal–wavelet method study allowed quantification of the processes affecting groundwater levels and provided an insight into their implications in exploring groundwater level management.