HYDROCHEMICAL CHARACTERIZATION OF GROUNDWATER OF THE RARITAN BASIN

The Raritan Basin is the largest River Basin in New Jersey, serving as a main source of water for drinking and agricultural purposes. Hydrochemical assessment of the groundwater was carried out in the basin to provide awareness on the groundwater speciation. Four different sampling cycles were analyzed, using data from New Jersey AGWQMN. This study uses a multivariate statistical approach to describe the groundwater chemistry in the study area. Other approaches were also applied to determine the suitability of the groundwater for irrigation purposes. The study will identify the main processes controlling the groundwater regime. Based on the Kaiser criteria, the principal components were obtained from the data for the major ions controlling the groundwater speciation. Anthropogenic influence such as road deicing and geogenic processes like rock weathering, was identified as the major influence on the groundwater chemistry by Principal component analysis. This study identified different types of water in the basin in the different cycles. All sampling cycles showed similar characteristics, CaHCO₃, mixed CaMgCl, and CaCl water types. With some exceptions, two monitoring wells from the first and third cycle indicated a NaCl water type. This result shows that the Raritan basin, originally identified as calcium bicarbonate is still on the path towards a NaCl dominant water. The water’s high salinity may be attributed to seasonal deicing salt application. The use of piper diagrams also showed similar characteristics as indicated by the PCA in all sampling cycles. Analysis of sodium adsorption ratio, specific conductivity, magnesium hazard and permeability index were used to evaluate the groundwater suitability for irrigation. The groundwater is largely suitable for irrigation. The hydrochemical analysis provides a robust assessment of the groundwater speciation, providing more awareness for watershed decision making in the Raritan Basin.