Flood modeling in Samsun Engiz Stream: Evaluation of the adequacy of river sections with HEC-RAS

Year 2025, Volume: 7 Issue: 1, 16 - 23, 30.06.2025

Vahdettin Demir , Nazire Göksu Soydan Oksal , Neslihan Beden

https://doi.org/10.51489/tuzal.1617697

Abstract

Floods pose a significant threat to communities, particularly in Turkey's Central Black Sea Region, where they cause widespread economic, social, and environmental damage. The Ondokuzmayis district of Samsun has been especially vulnerable to recurrent flooding, emphasizing the need for precise risk assessments and effective flood management strategies. In this study, the flood modelling of Engiz Stream, located in the Ondokuzmayis district of Samsun, was conducted using one-dimensional modeling due to its speed, low computational cost and ease of implementation. Hydraulic modeling was performed in HEC-RAS using flow data from Ballıca Station on Engiz Stream and statistical distributions from the EasyFit software library. In the study, flow rates for 25, 50, 100, and 500-year flood return periods (Q25: 431 m³/s, Q50: 479.87 m³/s, Q100: 531.75 m³/s, Q500: 665.37 m³/s) were calculated, and the flow was modeled using a 5-meter resolution digital surface model. The modeling results indicated that while the cross-sections in urban areas were adequate, the river cross-sections in the agricultural areas where the river flows into the Black Sea were insufficient for the Q25 flow rate and beyond.

Keywords

Samsun , Engiz Stream , Flood Modeling , HEC-RAS

Project Number

101003534

Thanks

The authors extend their gratitude to the Samsun State Hydraulic Works (DSİ) 7th Regional Directorate and its employees for their support in data provision. Additionally, the authors express their thanks to the SCORE project (Smart Control of the Climate Resilience in European Coastal Cities) (Project No: 101003534) for funding support.

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