Assessment of groundwater recharge and connectivity with surface water in a mountainous watershed using natural tracers in Daejeon, Korea

• Published in: Environmental earth sciences 2023-11, Vol.82 (22), p.530, Article 530
• Main Authors: Choi, Hanna, Lee, Chung-Mo, Jo, Hui Je, Shim, Byoung Ohan
• Format: Article
• Language: English
• Subjects: Altitude; Altitude effects; Anthropogenic factors; Biogeosciences; Chemical composition; Connectivity; Contaminants; Earth and Environmental Science; Earth Sciences; Environmental Science and Engineering; Geochemistry; Geology; Groundwater; Groundwater recharge; Headwaters; Human influences; Hydrochemicals; Hydrochemistry; Hydrology; Hydrology/Water Resources; Isotope composition; Isotopes; Meteoric water; Mountain hydrology; Mountain regions; Mountainous areas; Mountains; Original Article; Resource management; Streams; Strontium 87; Strontium isotopes; Surface water; Surface-groundwater relations; Terrestrial Pollution; Tracers; Water analysis; Water bodies; Water budget; Water quality; Water resources; Water resources management; Water sampling; Water supply; Watersheds; Weather; Weather conditions
• ISSN: 1866-6280; 1866-6299
• DOI: 10.1007/s12665-023-11209-2

The water supply from headwater streams in mountainous regions is considered an important source for sustaining both water quality and quantity in lowland areas. The Korean terrain is characterized by mountainous regions, the hydrological environment is significantly impacted by seasonal weather conditions. This study focused on investigating the hydrochemistry and isotopic composition of groundwater and surface water to identify hydrological connectivity within a mountainous watershed area in Daejeon, Korea. The estimated recharge rate using water budget methods suggests that approximately 20% of the total precipitation contributes to groundwater recharge in this site. The δ 18 O–δ 2 H values of the water samples indicate a meteoric water source for groundwater recharge, while the isotope composition of surface water reveals altitude effects, implying that groundwater recharges at a higher altitude region. Additionally, water revealed altitude effects suggesting that the groundwater was inferred to recharge at a higher altitude region. The hydrochemical conservative components ( 87 Sr/ 86 Sr ratio and Cl − ) indicate that this watershed undergoes temporary similar water–rock interactions along its flow path, but it is also impacted by anthropogenic contaminants from the surrounding public area. The results of the three-component endmember mixing analysis demonstrate that groundwater is predominantly influenced by surface water, indicating a close interrelationship among various water bodies in mountain hydrology. These findings provide a comprehensive approach to water resource management by combining recharge rate estimation and the assessment of water body connectivity using natural tracers.