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 GEP  Vol.5 No.3 , March 2017
Application of Flood Routing Model for Flood Mitigation in Orashi River, South-East Nigeria
Abstract: The study focused on the application of Flood Routing Models for Flood Mitigation in Orashi River, South-East Nigeria. Flood data were collected for the study area and subjected to statistical analysis. Three flood Routingmodels were comparatively applied including Muskingum model, Level Pool model and Modified Pul’s model. Assumed routing period of 2.3 hours which helped to check excessive flood at the downstream section of the river was used. Also a dimensionless weighting factor of 0.15 was also adopted. Muskingum model and Level Pool model which represent linear relationship between measured outflow and predicted outflow for specified inflow and time change of one hour gave high and positive values of coefficients of correlations of 0.9769 and 0.9732 respectively. The Modified Pul’s model which also represents a linear relationship between measured outflow and predicted outflow for specified inflow and a time change for one hour showed the highest coefficient of correlation of 0.9984 and lowest standard error of 0.1749. Though, flood models of the Muskingum method and Level Pool method exhibited good correlation, their prediction differed significantly with the corresponding models of original data sets because of high standard error and thus not adequate for field application in similar rivers. A design application was carried out using the Modified Pul’s model. The values obtained for routed storage capacity was 348 m3 while the designed capacity was 354 m3. It is recommended that dredging of the river is carried out to achieve the designed capacity. This would eliminate the risk of flooding. The results of the study will serve useful purposes in predicting flood events and design of flood control works in similar basins.
Cite this paper: Ogbonna, D. , Okoro, B. and Osuagwu, J. (2017) Application of Flood Routing Model for Flood Mitigation in Orashi River, South-East Nigeria. Journal of Geoscience and Environment Protection, 5, 31-42. doi: 10.4236/gep.2017.53003.
References

[1]   Kulandaiswamy, V.C. (2006) A Note on Muskingum Method of Flood Routing. Journal of Hydrology, 4, 273-276.
https://doi.org/10.1016/0022-1694(66)90085-0

[2]   NEST (1991) Flood Hazard Assessment, Management and Mitigation Measures. Nigerian Environmental Study/Action Team NEST Publication, Ibadan, 67-70.

[3]   Pitt, P.H. (2007) Lessons from 2007 Floods. Pitt Review Report, Lancaster.

[4]   Smith, K. (2006) Environmental Hazards. Routledge, London, 301-314.

[5]   Akin, T. (2009) Strategies for Combating Urban Flooding in a Developing Nation: A Case Study from Ondo, Nigeria. Environmentalist, 14, 57-62.

[6]   NEST (1991) National Environmental Survey/Action Flood Report.

[7]   King, L. (2014) Flood Routing. National Engineering Handbook. US Department of Agriculture. Part 630 chap 17.

[8]   Chadwick, A. and Morfeit, J. (1993) Hydraulics in Civil and Environmental Engineering. E & F N Spon, London, p. 317.

[9]   Garg, S.K. (2008) Irrigation Engineering and Hydraulic Structures. Khanna Publishers, Delhi, p. 937.

[10]   Han, D. (2010) Concise Hydrology. Bookboon.com Ltd., London, 119-124.

[11]   Ogbonna, O. (2015) Application of Flood Routing Model for Flood Mitigation in Orashi River, South-East Nigeria. PhD Thesis, Federal University of Technology, Owerri. (Unpublished)

[12]   NEMA (2012) Evaluation of Flood Hazards. Prepared by EnvironmentalImpact Assessment Department, 13-16.

[13]   Subramanya, K. (2009) Flow In Open Channels. 3rd Edition, Tata Mc Grow-Hill, New Delhi, 344-351.

 
 
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