Urban Flood Risk Mapping with Coupling Storm and Sanitary Analysis Software (ASSA) and HEC-RAS Model, Case Study of Ladan Urban Watercourse, Mashhad, Iran

Khashavarz, Reyhaneh; Malek Mohammadi, Bahram; Nik Sokhan, Mohammad; Bina, Keivan

doi:10.22077/jdcr.2025.9632.1150

Urban Flood Risk Mapping with Coupling Storm and Sanitary Analysis Software (ASSA) and HEC-RAS Model, Case Study of Ladan Urban Watercourse, Mashhad, Iran

Document Type : Original Article

Authors

Reyhaneh Khashavarz ¹

Bahram Malek Mohammadi ²

Mohammad Nik Sokhan ³

Keivan Bina ⁴

¹ Ph.D. Student, University of Tehran, Kish International Campus, Kish, Iran.

² Faculty Member, Department of Environmental Engineering, University of Tehran, Tehran, Iran.

³ Professor, Faculty of Environmental, University of Tehran, Iran.

⁴ Assistant, Department of Civil Engineering, Engineering Faculty & Disaster Risk Reduction Research Group, Khayyam University, Mashhad, Iran.

https://doi.org/10.22077/jdcr.2025.9632.1150

Abstract

Flooding is among the most destructive natural hazards, causing significant human and economic losses. Urban flood risk zoning offers an effective approach to mitigating such damages by identifying vulnerable areas and assessing hazard intensity, thereby enabling proactive planning and management. This study aimed to perform flood risk mapping of the Ladan watercourse in 9rd District of Mashhad city, Iran, through hydraulic and hydrological modeling. The analysis employed Storm and Sanitary Analysis (ASSA) and HEC-RAS 6.2 software. Rainfall–runoff modeling was based on a uniform rainfall pattern, while hydraulic simulations were conducted for return periods of 25, 50, and 100 years. Flood hazard zoning for the 100-year flood was prepared in accordance with Iranian Guideline for flood hazard mapping (Code 821), in which the product of flow depth and velocity (V×D) was considered as the flood hazard index. The findings revealed that the Ladan watercourse can convey floods with return periods of 25 and 50 years. However, during the 100-year flood, specifically, the initial 200 meters of the channel were identified as critical zones where overtopping and road inundation are likely to occur.

The outcomes of this research highlight the importance of flood risk zoning in supporting sustainable urban planning and flood management. The results provide a practical basis for prioritizing vulnerable zones and guide the development of preventive strategies and flood control structures.

Keywords

Risk Mapping

Urban Flooding

ASSA Software

HEC-RAS

Rainfall-Runoff

Subjects

Climate change

Azouagh, A. E., Bardai, R., Hilal, I., & El Messari, J. S. (2018). Integration of GIS and HEC‑RAS in floods modeling of Martil River (Northern Morocco). European Scientific Journal, 14(14), 130–142. https://eujournal.org/index.php/esj/article/view/10780.

Cao, W., Zhou, Y., Güneralp, B., Li, X., Zhao, K., & Zhang, H. (2022). Increasing global urban exposure to flooding: An analysis of long‑term annual dynamics. Science of the Total Environment, 817, 153012. https://doi.org/10.1016/j.scitotenv.2022.153012.

Cikmaz, B., Yildirim, E., & Demir, I. (2023). Flood susceptibility mapping using fuzzy analytical hierarchy process for Cedar rapids, Iowa. International Journal of River Basin Management. https://doi.org/10.1080/15715124.2023.2216936.

Emad‑o-din, S., Ahmadi, H., & Arkhi, S. (2023). Flood zoning of the Abr watershed in Shahroud city to reduce risk. Journal of Geographical Engineering of Trritory, 7(1), 107–120. [In Persian] https://doi.org/10.22034/jget.2023.154398

Esmaeilialavijeh, E., Karimi, S., & Avipoor, F. (2020). Vulnerability Assessment in urban areas against flood with fuzzy logic (case study: Tehran districs 22). Environmental Science and Technology, 22(3), 349-361. [In Persian] https://doi.org/10.22034/jest.2020.10940

Etemadi, M., Azizian, G., & Akbari, M. (2012). Application of geographic information system (GIS) in flood zoning (case study: Karde River in Khorasan‑Razavi). Proceedings of the 3rd National Conference on Integrated Water Resources Management, Sari, University of Agricultural Sciences and Natural Resources. [In Persian] https://www.civilica.com/Paper-NCWRM03-NCWRM03_174.html

7. Fotouhi, S., & Kiani, S. (2015). Micro-zonation of the Urban Flood Risk Model Using AHP (Case Study: Nahavand city). Quarterly Journal of Environmental-based Territorial Planning, 8(29), 133-152. [In Persian] https://journals.iau.ir/article_515572.html

Ghahreman, B. (1998). Derivation of Intensity-Duration-Frequency-Area (IDFA) Curves for Mashhad City, Journal of Advanced Material in Engineering, 17(2): 69-81. [In Persian] https://dor.isc.ac/dor/20.1001.1.2251600.1377.17.2.7.3

(2023). Study report on flood vulnerability assessment and risk analysis of Mashhad. Mashhad municipality. [In Persian] Retrieved from https://drive.google.com/file/d/11ZpuLTg-g79E_xryXZcCLAnxfIuS-GjQ/view

Iran Ministry of Energy. (2016). Principles and criteria for surface wastewater and water network designs, Code 118. Tehran: Plan and Budget Organization Publications. [In Persian] https://waterstandard.wrm.ir/cs/WRMResearch/278/293

Iran Ministry of Energy. (2020). Manual for providing flood risk map, Code 821. Tehran: Plan and Budget Organization. [In Persian] https://waterstandard.wrm.ir/cs/WRMResearch/278/396

Iroume, J. Y.-A., Onguéné, R., Djanna Koffi, F., Colmet‑Daage, A., Stieglitz, T., Essoh Sone, W., Bogning, S., Olinga Olinga, J. M., Ntchantcho, R., Ntonga, J.-C., et al. (2022). The 21st August 2020 flood in Douala (Cameroon): A major urban flood investigated with 2D HEC‑RAS modeling. Water, 14(11), 1768. https://doi.org/10.3390/w14111768.

Manandhar, B., Cui, S., Wang, L., & Shrestha, S. (2023). Urban flood hazard assessment and management practices in south asia: A review. Land, 12, 627. https://doi.org/10.3390/land12030627

O’Donnell, E. C., & Thorne, C. R. (2020). Drivers of future urban flood risk. Philosophical Transactions A, 378, (2168). https://doi.org/10.1098/rsta.2019.0216

Tajik, F., Rahmanzadeh, S. A., Aghili, S. V., & Nematianarchi, D. (2021). Analysis of the role of television in managing the spring flood crisis of 1998. Communication Research Quarterly, 28(3), 125–159. [In Persian] https://doi.org/10.22082/cr.2021.535017.2217

S. Army Corps of Enginners (USACE), 2010: HEC-RAS River Analysis System: Hydraulic reference manual, version 4.0. Hydrologic Engineering Center, Davis, US.

Vafaei, M., Dastourani, M. T., & Vorstemi-Khalaj, M. (2023). Flood hazard assessment of pardis campus of Ferdowsi university of Mashhad and presentation of management scenarios using HEC-RAS model. Modeling and Management of Water and Soil, 3(3), 225–239. [In Persian] https://doi.org/10.22098/mmws.2022.11815.1173

Vaidyanathan, G. (2023). How India is battling deadly rain storms. Nature, 614, 210–213. https://doi.org/10.1038/d41586-023-00445-3.

Xu, H., Zhong, T., Chen, Y., & Zhang, J. (2023). How to simulate future scenarios of urban stormwater management? A novel framework coupling climate change, urbanization, and green stormwater infrastructure development. Science of the Total Environment, 874, Article 162399. https://doi.org/10.1016/j.scitotenv.2023.162399

Yazdani, M. H., Ghasemi, M., Saleki Maleki, M. A. & Afkhami, F. (2018). Micro-zoning vulnerability of cities against flood risk (case study: Tabriz city). Quarterly Scientific Research Journal of Rescue & Relief, 9(36), 33-45. [In Persian] https://www.sid.ir/paper/190832/en.

Zarei, M., Zandi, R., & Naimitabar, M. (2022). Assessment of flood potential using data mining modelsof Support Vector Machine, Chaid and Random Forest (Case study: Frizi watershed). Journal of Watershed Management Research, 13(25), 133–144. [In Persian] https://doi.org/10.52547/jwmr.13.25.133

Zhi, G., Liao, Z., Tian, W., & Wu, J. (2020). Urban flood risk assessment and analysis with a 3D visualization method coupling the PP‑PSO algorithm and building data. Journal of Environmental Management, 268, 110521. https://doi.org/10.1016/j.jenvman.2020.110521