1 National Centre for Hydro–Meteorological Forecasting;;;;

2 Vietnam Institute of Meteorology, Hydrology and Climate Change;

*Corresponding author:; Tel.: +84–912967014


Flash flood is a natural disaster occurring in a short time due to heavy rainfall combined with topography, geomorphology, economic growth in the basin. Although it happens on a small scale but it leaves far–reaching destruction in its wake. Recent years have recorded, several consecutive flash flood events causing great damage in the mountainous area of Quang Nam province. For example, in 2020, the successive flash floods and landslides occurring in October and November has been a pressing disaster problem which causes great loss of life and property. Flash flood prediction poses a big challenge for not only Vietnamese but also international scientists. The general method of flash flood prediction is based on threshold runoff and bankfull discharge. Currently, the Viet Nam Meteorological and Hydrological Administration is selected as Regional Centre for supporting flash flood warning by the World Meteorological Organization, has received the “Southeast Asia Flash Flood Guidance System (SEAFFGS)” developed by the U.S Hydrological Research Center and initially applied in flash flood and landslide warning. This paper presents the results of a methodological application for determining the guidance threshold runoff and bankfull discharge for flash flood warning in the SEAFFGS, which will be applied for the mountainous area of Quang Nam province as a pilot study area. The research results will be the first step for studies to determine the threshold runoff formed for flash flood warnings and can be referred for other mountainous regions of Vietnam.


Cite this paper

Phuong, T.T.; Mai, T.T.; Quynh, N.T.N.; Kien, N.T.; Dung, L.H. Exploiting SEAFFGS to determine threshold runoff and bankfull discharge – pilot application for Quang Nam province. VN J. Hydrometeorol. 2022, 13, 25-36. 


1. Hall, J.. Flash flood forecasting. World Meteorological Organization, 1981.

2. National Research Council. Flash Flood Forecasting Over Complex Terrain: With an Assessment of the Sulphur Mountain NEXRAD in Southern California. Washington, DC: The National Academies Press, 2005.

3. Philadelphia/Mt Holly. What is flash flooding. 2018. Available online:

4. Georgakakos, K. On the Design of National, Real–Time Warning Systems with Capability for Site–Specific, Flash–Flood Forecasts. Bull. Am. Meteorol. Soc. 1986, 67, 1233–1239.

5. Cao, D.D.; Le, B.H. Pipe floods and flash floods. Causes and solutions. Agricultural Publisher, 2000, 1, p. 96.

6. Ngo,  D.T. Flash flood and mitigating flash floodst. Agricultural Publisher, 2006.

7. La, T.H.; Nguyen, T.T. Necessary knowledge about flash floods. Map Publisher, 2009.


9. Viet Nam Institute of Meteorology, Hydrology and Climate Change, Ministry of Natural resources and Environment. Project report Investigation, survey, and mapping of flash flood risk zoning for the Central and Highland regions, and develop a pilot system of flash floods warning for high–risk localities in order to serve the purpose of planning, directing and operating disaster prevention and climate change adaptation, 2019.

10. Viet Nam Institude of Geosciences and Mineral Resources, Ministry of Natural resources and Environment. Report Current status map of landslides at scale 1:50,000 in Quang Nam province, Project on Investigating, evaluating and zoning the risk of landslides in mountainous areas of Vietnam, 2019.

11. Riggs, H.C. Estimating flow characteristics at ungaugedsites. In: Beran, M.A., Brilly, M., Becker, A., Bonacci, O. (Eds.). Regionalization in Hydrology, IAHS, 1990, 191,150–161.

12. Nixon, M. A study of bankfull discharges of rivers inEngland and Wales. Mm. Preo. Instn. Civ. Engrs. 1959, 6322, 157–174.

13. Williams, P. Bankfull Discharge of rivers. Water Resour. Res. 1978, 6, 1–14.

14. Carpenter, T.M.; Sperfslage, J.A.; Georgakakos, K.P.; Sweeney, T.; Fread, D.L. National threshold runoff estimation utilizing GIS in support of operational flash flood warning systems. J. Hydrol. 1999, 224, 21–44.

15. SEAFFGS. 2022.­_CONSOLE/.

16. Wang, C.T.; Gupta, V.K.; Waymire, E. A geomorphologicsynthesis of nonlinearity in surface runoff. Water Resour. Res. 1981, 17(3), 545–554.

17. Georgakakos, K.P.; Unnikrishna, P.V.; Bravo, H.R.; Cramer, J.A. A national system for determining threshold runoff values for flash–flood prediction. Issue Paper, Department of Civil and Environmental Engineering and Iowa Institute of Hydraulic Research, The University of Iowa, Iowa City, IA, 1991.

18. Georgakakos, K.P. Modern Operational Flash Flood Warning Systems Based on Flash Flood Guidance Theory: Performance Evaluation. Proceedings of International Conference on Innovation, Advances and Implementation of Flood Forecasting Technology, Bergen–Tromsø, Norway, 2005, pp. 1–10.

19. Georgakakos, C.R.; Shamir, E.; Randall, B. Sothesast Asia Flash Flood Guidance System (SEAFFGS) system Administration User’s Guide. Hydrologic Research Center, 2002.

20. Shamir, E.; Ben-Moshe, L.; Ronen, A.; Grodek, T.; Enzel, Y.; Georgakakos, K.; Morin, E. Geomorphology–based index for detecting minimal flood stages in arid alluvial streams. Hydrol. Earth Syst. Sci. Discuss. 2012, 9, 12357–12394.

21. Zhai, X.; Guo, L.; Liu, R. et al. Rainfall threshold determination for flash flood warning in mountainous catchments with consideration of antecedent soil moisture and rainfall pattern. Nat. Hazards 2018, 94, 605–625.