Assessment and Mitigation of Land-Based Pollutants and Climate Change Impacts on Coastal Water Quality

Cebe, K., Balas, L., and Yıldırım Fidanoğlu, P., 2024. Assessment and mitigation of land-based pollutants and climate change impacts on coastal water quality. In: Phillips, M.R.; Al-Naemi, S., and Duarte, C.M. (eds.), Coastlines under Global Change: Proceedings from the International Coastal Symposium (ICS) 2024 (Doha, Qatar). Journal of Coastal Research, Special Issue No. 113, pp. 402-406. Charlotte (North Carolina), ISSN 0749-0208. This study presents the development and application of an integrated numerical coastal water quality model to assess the impact of land-based pollutants and climate change on Samsun Bay, located on the eastern coast of the Black Sea in Türkiye. Monthly measurements of various water quality parameters, including temperature, salinity, pH, turbidity, dissolved oxygen, and nutrient concentrations, were conducted for one year. Using the Storm Water Management Model (SWMM, v5.1), land-based pollutant loadings from urban and industrial sources were estimated, encompassing total suspended solids, biological and chemical oxygen demand, inorganic phosphorus, ammonia, nitrite, and nitrate. Three-dimensional coastal hydrodynamics, transport, and water quality model, HYDROTAM-3D, was then employed to simulate coastal circulations and changes in water quality parameters. The model's effectiveness was validated by comparing its estimates with field measurements from six monitoring stations within the bay, revealing close agreement and capturing temporal variations effectively. The study highlighted the hypertrophic status of Samsun Bay coastal waters. To address this issue, the model projected the impact of implementing best management practices, including remediation, street cleaning, good agricultural practices, and enhanced wastewater treatment before discharge, on land-based pollution through 2040. The results indicated a substantial improvement in Samsun Bay water quality with implementing these practices, emphasizing the significance of sustainable management strategies to mitigate the adverse effects of land-based pollutants on coastal ecosystems.