Characterizing groundwater hydrochemistry and stable isotopes in northern Namibia landscapes with an emphasis on seasonal variations
Year: 2026
Type: article
Abstract: Groundwater is Namibia’s primary water source, but it is increasingly vulnerable to recharge fluctuations. This study assessed seasonal variations in groundwater hydrochemistry and stable isotopes across three contrasting landscapes – Okatjandja, Uukolonkadhi, and Okongo – over two years, covering wet and dry seasons. Most major ions met Namibia and WHO drinking standards, except Omaoipanga (B6), which exceeded fluoride (>1.5 mg L−1), sulphate (up to 450 mg L−1), and TDS (>1 000 mg L−1) standards. The water quality index revealed better quality during wet seasons, and Okongo had the best overall water quality. Significant seasonal differences were only observed for Na+ and K+. Hydrochemical facies were dominated by calcium bicarbonate (Ca-Mg-HCO3) and sodium bicarbonate (Na-HCO3) across seasons, with rock weathering as the main control. Stable isotopes confirmed meteoric recharge; Okongo showed depleted signatures, while Okatjandja exhibited isotopic enrichment signatures. These findings highlight the need for targeted groundwater management amid climatic stress.
Source: Hydrological Sciences Journal
Institution: University of Namibia
Language: English
Subfield: Geochemistry and Petrology
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: hybrid
OpenAlex ID: W7222120965