Abstract
Recreational water quality in coastal areas is vital for public health, especially in urban regions. In this study, a recreational water quality index (RWQI) tailored to the Red Sea coastline in Jeddah, Saudi Arabia, was developed to assess water quality at popular beaches. The samples were collected from three different locations. To develop the RWQI, relevant water quality parameters, such as the pH, dissolved oxygen (DO), total nitrogen (TN), total phosphorus (TP), Escherichia coli (E. coli), and enterococci, were identified and weighted on the basis of their significance for recreational water safety. These parameters were rated according to the World Health Organization (WHO) and Saudi Arabia Ambient Water Quality Standards (SAAWQS). The results were then aggregated into a single index score reflecting the overall water quality. The results revealed that Obhur Al-Shamaliya exhibited generally good water quality, particularly in winter, with index scores ranging from 83 to 98, meeting both the WHO and Saudi standards. All three sites recorded poorer water quality during the second sampling period in summer, with nutrient enrichment and E. coli counts exceeding permissible limits (2,300, 3,875, and 2,58.13 CFU/100 mL, respectively), resulting in an index classification as unsuitable for recreational purposes. The urban runoff sites were at high risk, with elevated pollution. Moreover, a one-way ANOVA test confirmed that the seasonal variation in the RWQI was statistically significant (F = 8.29, p = 0.045), emphasizing the influence of environmental factors, such as temperature and runoff, on recreational water quality. These findings underscore the need for season-specific monitoring and management strategies in coastal recreational areas.
Acknowledgements
The project was funded by the KAU Endowment (WAQF) at King Abdulaziz University, Jeddah, Saudi Arabia. The authors therefore acknowledge with thanks the WAQF and the Deanship of Scientific Research (DSR) for technical and financial support. The authors also express their sincere gratitude to the Department of Environment, Faculty of Environmental Sciences at King Abdulaziz University, for providing the laboratory facilities and resources essential for conducting the experimental work and analysis in this study.
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Almeelbi, T., Alghamdi, F. Development and evaluation of a recreational water quality index for the Red Sea Coastline, Saudi Arabia.
Sci Rep (2026). https://doi.org/10.1038/s41598-026-54623-9
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DOI: https://doi.org/10.1038/s41598-026-54623-9
Keywords
- Coastal pollution
- Microbiological indicators
- Recreational water quality index (RWQI)
- Red sea
- Water quality assessment
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