Flood Zonation and Morphological Analysis of Qaraso River using HEC-RAS Hydrodynamic Model (From Pirazmeyan Village to the Confluence of Ahar-Chay River)

Document Type : مقاله پژوهشی


1 University of Tabriz

2 University of Tehran


1. Introduction
Nowadays floods are considered as one of the greatest threats in terms of social security and sustainable development which affect 20 to 300 million peoples each year (Hirabayashi & Kanae, 2009). In recent decades, many studies have been carried out on floods which have mainly approached to flood risk management. Flood inundation models are defined as the tools which could simulate the rivers hydraulic and also occurred floods in flood plains (Horrit, 2007). In other words, flood inundation models are useful tools for flood plain management. This ability in flood prediction, and also flood damage reduction by protecting of near river land use, improving the knowledge of indigenous people of flood plain, and preventing the construction in banned area of flood plain is very useful (Di Baldassarre, 2010). In this study the risk of flood occurring for different return period along 72 Kilometer in Qaraso River have been investigated.
2. Materials and Methods
This research is based on filed studies and 1:2000 scale topographic maps that provided by Ardabil regional water authority. The 1:100000 scale geological maps, satellite imagery such as IRS and Google Earth and also hydrometric data of Dostbaglo and Arbab Kandi hydrometric station, considered as essential data. The HEC-RAS model could calculate the water surface profile in stable flow gradual variable in rivers and artificial channels in the subcritical, supercritical and complex regimes. The calculation of water surface profile carried out from one cross section to other cross, step by step, solving energy equation in standard way.
3. Results and Discussion
In this study in order to estimate the frequency distribution of floods we used Pearson Type III distribution in logarithm base 10, which provided by USA federal organizations of rivers reconstruction. Then flood peak discharges with different return period and its probability of occurrence has been calculated for important hydrometric station namely: Dostbaglo and Arbab kandi. According to the flood-prone zonation map, we observed the maximum wide of flood-prone area in reach2 to reach4 of river (from Qadirlo Village to Lalganj Village) in different period. In these reaches the width of flood-prone area in 25 years return period is about 500 meter on average. In first and some parts of reach6 and reach7, due to narrowing of channel and some obstacle the wide of flood-prone area was decreased and instead the water depth has been increased. Regarding to the placement of the Qadirlo, Kangarlo, Agh‌ Darag and Dostbaglo villages in the margin of the Qaraso River, the flood zonation in this rivers should be considered. The main landuse of Qaraso riparian is assigned to agriculture and orchards. By overlay the flood zonation maps with satellite imagery we observed that the main portion of this agriculture lands, has been located in the river bed and riparian zone (according to 25 years return period), are at risk of flooding. This could lead to heavy damage for farmers. For example, the flood events with 25 years return period, affected about 1085 hectare of farmland and orchard that located beside Qaraso River and lead to heavy damages.
4. Conclusions
Regarding to notable encroachment by farmers in the Qaraso river bed, the Flood risk is very important. The flood-zoning of Qaraso River shows that wide part of farmlands and orchards and also part of the facility located around the Qaraso River (nearby the village of kangarlo) have been exposed to floods with 25 years return period. Therefore, according to article 10 of regulation of bed and riparian of rivers the regional water authority of Ardabil should determine the condition of this high risk area. Accordingly, the floodplain management should be considered as an important and essential issues.


ارزنلو، ابوالفضل؛ 1394. بررسی شکست سد خاکی شهر چای ارومیه ناشی از روگذری جریان و پهنه‌بندی سیلاب با استفاده از مدل HEC- RAS و GIS. پایان‌نامه کارشناسی ارشد، استاد راهنما: یوسف حسن زاده، سازه‌های هیدرولیکی، دانشگاه ارومیه.
رضایی مقدم، محمدحسین؛ رجبی، معصومه؛ دانشفراز، رسول؛ خیری زاده، منصور؛ 1395. پهنه‌بندی و بررسی اثرات مورفولوژیکی سیلاب‌های رودخانه زرینه‌رود. جغرافیا و مخاطرات محیطی، شماره 17، 1-20.
غفاری، گلاله ؛ امینی، عطااله؛ 1389. مدیریت دشت‌های سیلابی با استفاده از سیستم اطلاعات جغرافیایی (GIS) (مطالعه موردی رودخانه قزل‌اوزن). فضای جغرافیایی، شماره 32، 134-117.
قمی اویلی، فرشته؛ صادقیان، محمدصادق؛ جاوید، امیرحسین؛ میرباقری، سیداحمد؛ 1389. شبیه‌سازی پهنه‌بندی سیل با استفاده از مدل HEC-RAS. علوم و فنون منابع طبیعی، شماره 1. 115- 105.
یاسی، مهدی؛ 1394. مهندسی رودخانه پیشرفته (قسمت اول)، جزوه درسی کارشناسی ارشد و دکتری، انتشارات دانشگاه ارومیه.
یمانی، مجتبی؛ تورانی، مریم ؛ چزغه، سمیرا؛ 1391. تعیین پهنه‌های سیل گیر با استفاده از مدل HEC-RAS (مطالعه موردی: بالادست سد طالقان از پل گلینک تا پل وشته). جغرافیا و مخاطرات محیطی، شماره 1، 1-16.
Bates, P. D., 2004. Computationally efficient modelling of flood inundation extent. In European Science Foundation Workshop, edited by BIOS, Bologna.
Brunner, Gary.W 2010. HEC-RAC River analysis system hydraulic reference manual, us army corps of engineers, version 4.1.
Cameron, T., & Ackerman, P. E., 2009. HEC-GeoRAS: GIS Tools for the Support of HEC-RAS Using ArcGIS, Version 4.2, CPD83. US Army Corps of Engineers, Institute for Water Resources, Hydrologic Engineering Center: Davis, California, 246.
Di Baldassarre, G., 2012. Floods in a changing climate: Inundation modelling (Vol. 3). Cambridge University Press.
Gül, G. O., Harmancıoğlu, N., & Gül, A., 2010. A combined hydrologic and hydraulic modeling approach for testing efficiency of structural flood control measures. Natural hazards, 54(2), 245-260.
Hirabayashi, Y., & Kanae, S., 2009. First estimate of the future global population at risk of flooding. Hydrological research letters, 3, 6-9.
Horritt, M. S., Di Baldassarre, G., Bates, P. D., and Brath, A., 2007. Comparing the performance of 2-D finite element and finite volume models of floodplain inundation using airborne SAR imagery. Hydrological Processes, 21, 2745–2759.
Jha, A. K., Bloch, R., & Lamond, J., 2012. Cities and flooding: a guide to integrated urban flood risk management for the 21st century. The World Bank.
Knebl, M. R., Yang, Z. L., Hutchison, K., & Maidment, D. R., 2005. Regional scale flood modeling using NEXRAD rainfall, GIS, and HEC-HMS/RAS: a case study for the San Antonio River Basin Summer 2002 storm event. Journal of Environmental Management, 75(4), 325-336.
Kundzewicz, Z. W., Hirabayashi, Y., & Kanae, S., 2010. River floods in the changing climate—observations and projections. Water Resources Management, 24(11), 2633-2646.
Maidment, D. R., & Tate, E. C., 1999. Floodplain mapping using HEC-RAS and ArcView GIS (Doctoral dissertation, Center for Research in Water Resources, University of Texas at Austin).
Merwade, V., 2004. Geospatial description of river channels in three dimensions (Doctoral dissertation).
Mosquera-Machado, S., & Ahmad, S., 2007. Flood hazard assessment of Atrato River in Colombia. Water resources management, 21(3), 591-609.
Patro, S., Chatterjee, C., Singh, R., & Raghuwanshi, N. S., 2009. Hydrodynamic modelling of a large flood‐prone river system in India with limited data. Hydrological Processes, 23(19), 2774-2791.
Wilby, R. L., & Keenan, R., 2012. Adapting to flood risk under climate change. Progress in Physical Geography, 36(3), 348-378.
Wohl, E. E. (Ed.)., 2000. Inland flood hazards: human, riparian, and aquatic communities. Cambridge University Press.
Yang, J., Townsend, R.D., & Daneshfar, B., 2006. Applying the HEC-RAS model and GIS techniques in river network floodplain delineation. Canadian Journal of Civil Engineering, 33 (1), 19-28.