Assessing the influence of precipitation on shallow groundwater table response using a combination of singular value decomposition and cross-wavelet approaches

Identifying the spatiotemporal change of the groundwater table to precipitation at the river basin scale can be important for regional water resource management. In this study, we proposed a method that combines singular value decomposition and cross-wavelet approaches to analyze the relationship between groundwater level dynamics and precipitation. The method was applied to the Naoli River Basin, Northeast China. Moreover, the method of continuous wavelet using fast Fourier transform was also used to reveal clearly the relationship between groundwater level and heavy precipitation. The results showed that the major mode of relationship between groundwater and precipitation was divided into four patterns in the study area. In general, the lag time is 27.4 (standard deviation: ±8.1) days in pattern 1, 107.5 (standard deviation: ±13.2) days in pattern 2, 139.9 (standard deviation: ±11.2) days in pattern 3, and 173.4 (standard deviation: ±20.3) days in pattern 4, respectively. In addition, the response of groundwater level dynamics is very sensitive to heavy precipitation in all patterns. Therefore, enhancing the utilization of heavy rainfall and flood resources is an effective way to increase groundwater recharge in this basin