Wavelet and cross-wavelet analysis of groundwater quality signals of saltwater intruded coastal aquifers

Abstract

Monitoring wells are used to collect temporal data on the groundwater table and the salinities. This study uses wavelet analysis for analysing the temporal patterns of groundwater table and salinity levels for a saltwater intruded coastal aquifer. The time series of groundwater table and salinity levels are analysed using continuous wavelet transforms (CWT). Wavelet analysis is able to detect detailed temporal patterns in the time series of groundwater data. These analyses help in improving the water quality monitoring, modeling and determining pumping strategies for contaminated aquifers. Further, phase relationship between the two time series of groundwater table and the salinity levels is analysed using Cross Wavelet Transform (XWT). This analysis is able to provide information on the causative effect of groundwater table on the salinity concentrations along with their phase relationship in time‐frequency domain.