Faculty of Civil Engineering and Geosciences, Delft University of Technology, Stevinweg 1, 2628 CN Delft, The Netherlands.
Maas Geohydrologisch Advies, Zuidsingel 114, 4331RW Middelburg, The Netherlands.
Ground Water. 2019 Nov;57(6):886-894. doi: 10.1111/gwat.12891. Epub 2019 May 10.
Time series analysis is applied to identify and analyze a transition in the groundwater regime in the aquifer below the sand ridge of Salland in the Netherlands, where groundwater regime refers to the range of head variations throughout the seasons. Standard time series analysis revealed a discrepancy between modeled and observed heads in several piezometers indicating a possible change in the groundwater regime. A new time series modeling approach is developed to simulate the transition from the initial regime to the altered regime. The transition is modeled as a weighted sum of two responses, one representing the initial state of the system, the other representing the altered state. The inferred timing and magnitude of the change provided strong evidence that the transition was the result of significant dredging works that increased the river bed conductance of the main river draining the aquifer. The plausibility of this explanation is corroborated by an analytical model. This case study and the developed approach to identify a change in the groundwater regime are meant to stimulate a more systematic application of time series analysis to detect and understand changes in groundwater systems which may easily go unnoticed in groundwater flow modeling.
时间序列分析用于识别和分析荷兰萨兰含水层下砂脊下方地下水状态的转变，其中地下水状态是指整个季节水头变化范围。标准时间序列分析显示，几个测压计中的模型化和观测到的水头之间存在差异，这表明地下水状态可能发生了变化。开发了一种新的时间序列建模方法来模拟从初始状态到改变状态的转变。该转变被建模为两个响应的加权和，一个代表系统的初始状态，另一个代表改变的状态。变化的推断时间和幅度提供了强有力的证据，表明转变是由于疏浚工程增加了主要河流的河床导水率，从而导致了这种转变。该解释的合理性得到了一个分析模型的证实。这个案例研究和识别地下水状态变化的方法旨在促进更系统地应用时间序列分析来检测和理解地下水系统的变化，这些变化在地下水流动建模中可能很容易被忽视。
