A new approach to analyze climatic and anthropogenic impacts on groundwater level dynamics

摘要

Limitations in applying the Wiener-Multichannel filter to analyze anthropogenic influences on groundwater level dynamics require a new approach independent from reference observation wells. This article presents a simple approach to analyze the relation between groundwater elevations and climate parameters for groundwater monitoring wells. A theoretical "climatic groundwater level series" is derived from monthly climatic water balances considering the transforming effects of the unsaturated zone and local conditions on groundwater level dynamics. Comparing theoretical groundwater levels with observed groundwater level fluctuations allows analyzing the agreement with the temporal dynamics of climatic parameters as well as detecting possible anthropogenic influences. A total of 284 of 573 groundwater observation wells in Lower Saxony show natural groundwater level dynamics, while artificial impacts were found in 221 wells and 68 wells remain unclear. A classification was therefore possible for 88% of the wells. A high model performance was detected for wells without artificial impacts and with minor artificial impacts. A split-sample cross validation proves the predictive capacity of the model for wells with natural dynamics.