Coastal discharge extremes and their environmental impact on the Sea of Marmara

Increases in evaporation driven by global warming change the hydrological cycle by fueling extreme precipitation and exacerbating the frequency and intensity of extreme floods. Combined with the increase in terrestrial waste and pollutants, the changing climate exposes coastal zones to natural hazards. The Sea of Marmara, as an inland sea with a dense coastal population, is more vulnerable to such changes and subject to eutrophication and extreme environmental events (e.g., mucilage). Therefore, quantification of daily and along-coast variation of river discharge and evaluation of its annual trend of extremes are crucial. The daily discharges from the coastal watersheds Biga, Gönen, Susurluk, İznik-Gölayağı, and İzmit-Kiraz during the period 2010–2020 were evaluated using the observed stream flows at the gages near the coast. The extreme daily discharges observed in each watershed are 350, 250, 600, 18, and 45 m3 s–1, respectively. The upper limits for coastal discharges during flood events were estimated as 175, 100, and 300 m3 s–1 for the first three watersheds. Daily discharge extremes exhibit seasonal and spatial variations along the coastline, with higher flow rates predominantly occurring in the winter and early spring. The onsets of these variations differ, particularly among the southern rivers, and this spatial-temporal change is examined in relation to net precipitation rates and geomorphological characteristics.
Turkish Journal of Earth Sciences
Citation Formats
N. B. Başdurak, “Coastal discharge extremes and their environmental impact on the Sea of Marmara,” Turkish Journal of Earth Sciences, vol. 33, no. 3, pp. 384–394, 2024, Accessed: 00, 2024. [Online]. Available: