A High‐Resolution Stable Isotope Database Revealing Within‐City Tap Water Variability and Source‐Water Connectivity in Trinidad

ABSTRACT

This Data Note presents a georeferenced stable isotope dataset from the island of Trinidad, comprising 309 water samples collected between 2018 and 2026. The dataset includes measurements of δ ¹⁸ O, δ ² H and d ‐excess. Samples represent four major water types: precipitation ( N  = 72), tap water ( N  = 215), groundwater from wells ( N  = 13) and rivers and streams ( N  = 9). The observations span a wide isotopic range (δ ¹⁸ O: −8.74 to +1.01‰; δ ² H: −56.5 to +18.6‰; d ‐excess: −18.1‰ to 24.5‰), reflecting the influence of precipitation variability, evapoconcentration and tap water distribution mainly between the Northern Range and Northern Drainage Basin. By integrating precipitation, surface water, groundwater and distributed drinking‐water samples, the dataset provides a unique baseline for characterizing the isotopic composition of Trinidad's water resources. The database supports applications in hydrology, hydrogeology, ecohydrology and water‐resource management, while also contributing to regional efforts to improve stable isotope data coverage in the tropical Caribbean. The dataset is intended to facilitate future studies of water provenance, recharge processes, catchment response and climate–water interactions in small tropical island environments.