Adaptation of the visibility graph algorithm to find the time lag between hydrogeological time series

Estimating the time lag between two hydrogeologic time series (e.g. precipitation and water levels in an aquifer) is of significance for a hydrogeologist-modeler. In this paper, we present a method to quantify such lags by adapting the visibility graph algorithm, which converts time series into a mathematical graph. We present simulation results to assess the performance of the method. We also illustrate the utility of our approach using a real world hydrogeologic dataset.