Seasonal Variation Characteristics of Karst Groundwater Chemistry and Water Quality Assessment in the Northern Part of the Baiquan Spring Area

Abstract

Karst groundwater is the main water supply source for human consumption and living, and it is important to study the karst groundwater resources to ensure people’s water supply needs. In this study, the northern part of the Baiquan spring area in Hebei Province was taken as a research object. Based on the hydrogeochemical approach, the characteristics and mechanism of seasonal variations of karst groundwater in the area were studied, and the groundwater quality was evaluated. This paper mainly uses multivariate statistics, the Piper trilinear diagram, the ion ratio coefficient, and the water quality index (WQI) as water quality assessment methods. The sequence of the main ion abundance is as follows: Ca²⁺ > Mg²⁺ > Na⁺ > K⁺, \({\text{HCO}}_{3}^{ - }\) > \({\text{SO}}_{4}^{{2 - }}\) > Cl^–, and the ion content showed a downward trend from the dry season to the wet season. The hydrochemical type in the dry season has changed compared with that in the wet season. The rate of carbonate rock dissolving in most of the study area waters in the wet season was higher than in the dry season. WQI calculation results show that most of the groundwater belongs to class II water quality, and the water quality in the wet season is better than that in the dry season. Studying different seasonal changes in groundwater chemistry can provide a reference for an in-depth understanding of karst groundwater chemistry characteristics and water resources protection in the spring area.