Event-Based Geospatial Assessment of Flood Inundation and Relative Risk in an Urban Watershed: Evidence from Istanbul, Türkiye

Cem Kırlangıçoğlu; Tauseef Ahmad

Event-Based Geospatial Assessment of Flood Inundation and Relative Risk in an Urban Watershed: Evidence from Istanbul, Türkiye

Abstract

Flooding represents one of the most significant global natural hazards, with severe consequences for urban areas. Recent technological advancements and the development of geospatial models have enabled the creation of effective solutions for urban flooding and land use planning in flood-affected cities. The present study employs remote sensing and GIS-based spatial analysis techniques to provide an event-based assessment of flood inundation, exposure, and relative flood risk within the administratively defined urban area of Başakşehir District, Istanbul, Türkiye. Rather than developing a physically based predictive hydrodynamic model, the study aims to identify the spatial distribution of observed flood impacts and their relationship with land use, population exposure, topography, and meteorological conditions. The Multi-temporal Sentinel 1 (SAR) dataset was utilised to extract flood pixels and prepare flood maps, with a pre-flood dataset representing 24.90 km2 of permanent waterbodies, which increased to 45.18 km2 during the flood. The LULC classification of the pre-flood area revealed that the majority of the study area was covered by a built-up area, primarily in the central and southern parts of the territory. During the flood, it was observed that 8.13 km² of built-up area and 15.80 km² of fallow land were inundated, constituting 60% of the total inundation area. The relative flood risk assessment revealed that Şamlar and the military zone were classified as very high-risk areas, while several central and eastern subdistricts were identified as high-risk areas. The findings of this study are of significant benefit to strategic town planning and disaster management, with the incorporation of further hydrometeorological models serving to enhance the accuracy of the results.

Keywords

Thanks

The authors are thankful to USGS and ESA for the free availability of satellite datasets and TUIK, ADNKS, and ISKI for providing auxiliary datasets. The authors are also grateful to Sakarya University for providing a laboratory and infrastructure for the conduction of this research work.

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Details

Primary Language

English

Subjects

Population Trends and Policies, Land Use and Environmental Planning, City and Regional Planning

Journal Section

Research Article

Authors

Cem Kırlangıçoğlu ^*
0000-0002-5998-9496
Türkiye

Tauseef Ahmad This is me
0000-0003-0044-6347
India

Early Pub Date

June 19, 2026

Publication Date

-

Submission Date

April 18, 2026

Acceptance Date

May 11, 2026

Published in Issue

Year 2026 Number: Advanced Online Publication

IZ

https://izlik.org/JA76NZ56PJ

Cite

RIS / Bibtex

APA

Kırlangıçoğlu, C., & Ahmad, T. (2026). Event-Based Geospatial Assessment of Flood Inundation and Relative Risk in an Urban Watershed: Evidence from Istanbul, Türkiye. Sakarya Journal of Digital Humanities, Advanced Online Publication. https://izlik.org/JA76NZ56PJ

AMA

1.Kırlangıçoğlu C, Ahmad T. Event-Based Geospatial Assessment of Flood Inundation and Relative Risk in an Urban Watershed: Evidence from Istanbul, Türkiye. Sakarya Journal of Digital Humanities. 2026;(Advanced Online Publication). https://izlik.org/JA76NZ56PJ

Chicago

Kırlangıçoğlu, Cem, and Tauseef Ahmad. 2026. “Event-Based Geospatial Assessment of Flood Inundation and Relative Risk in an Urban Watershed: Evidence from Istanbul, Türkiye”. Sakarya Journal of Digital Humanities, no. Advanced Online Publication. https://izlik.org/JA76NZ56PJ.

EndNote

Kırlangıçoğlu C, Ahmad T (June 1, 2026) Event-Based Geospatial Assessment of Flood Inundation and Relative Risk in an Urban Watershed: Evidence from Istanbul, Türkiye. Sakarya Journal of Digital Humanities Advanced Online Publication

IEEE

[1]C. Kırlangıçoğlu and T. Ahmad, “Event-Based Geospatial Assessment of Flood Inundation and Relative Risk in an Urban Watershed: Evidence from Istanbul, Türkiye”, Sakarya Journal of Digital Humanities, no. Advanced Online Publication, June 2026, [Online]. Available: https://izlik.org/JA76NZ56PJ

ISNAD

Kırlangıçoğlu, Cem - Ahmad, Tauseef. “Event-Based Geospatial Assessment of Flood Inundation and Relative Risk in an Urban Watershed: Evidence from Istanbul, Türkiye”. Sakarya Journal of Digital Humanities. Advanced Online Publication (June 1, 2026). https://izlik.org/JA76NZ56PJ.

JAMA

1.Kırlangıçoğlu C, Ahmad T. Event-Based Geospatial Assessment of Flood Inundation and Relative Risk in an Urban Watershed: Evidence from Istanbul, Türkiye. Sakarya Journal of Digital Humanities. 2026. Available at https://izlik.org/JA76NZ56PJ.

MLA

Kırlangıçoğlu, Cem, and Tauseef Ahmad. “Event-Based Geospatial Assessment of Flood Inundation and Relative Risk in an Urban Watershed: Evidence from Istanbul, Türkiye”. Sakarya Journal of Digital Humanities, no. Advanced Online Publication, June 2026, https://izlik.org/JA76NZ56PJ.

Vancouver

1.Cem Kırlangıçoğlu, Tauseef Ahmad. Event-Based Geospatial Assessment of Flood Inundation and Relative Risk in an Urban Watershed: Evidence from Istanbul, Türkiye. Sakarya Journal of Digital Humanities [Internet]. 2026 Jun. 1;(Advanced Online Publication). Available from: https://izlik.org/JA76NZ56PJ