Hydrodynamic modeling for developing flood management strategies in the Ezine stream watershed, Türkiye: Fid-Bau Portal

Hydrodynamic modeling for developing flood management strategies in the Ezine stream watershed, Türkiye

Baycan, Hayri / Boyraz, Uğur

Ezine Stream Watershed, located in the Black Sea Region, Kastamonu, Türkiye, is a flood-prone area. A devastating flood occurred on August 11, 2021, causing 70 fatalities and considerable damage to structures along the stream channel. In this study, a hydrodynamic model of the watershed was developed using the Environmental Protection Agency’s Storm Water Management Model (EPA SWMM). The main channel and floodplain were simultaneously modeled utilizing the ‘irregular channel’ option in SWMM. The model was calibrated and verified using historical precipitation and discharge data. The validity was further evaluated by comparing outputs with observations from photos and videos taken on-site by local authorities and residents during the flood. The model was manually calibrated focusing on optimizing depression storage, soil drying time, curve number, and roughness coefficients for the channels and subcatchments. The model results served as the basis for implementing flood control strategies. Three scenarios were proposed for flood mitigation: the implementation of a newly designed improved channel, the construction of a flood control dam, and the installation of 15 check dams. The flood mitigation effectiveness of each scenario was assessed, and a thorough analysis was conducted to determine the optimal choice for the region. Consequently, each scenario played a significant role in reducing the peak flow rate. Among these scenarios, the flood control dam demonstrated the most substantial impact on reducing the flood flow. This study offers beneficial findings to the decision-makers on flood control planning in the watershed and contributes to future research in the field.