Performance of regional flood frequency analysis methods in KwaZulu-Natal, South Africa

Authors

  • JC Smithers 1. Bioresources Engineering, School of Engineering, University of KwaZulu-Natal, Private Bag X01, Scottsville, 3209, South Africa; 2. Jeffares & Green (Pty) Ltd, 6 Pin Oak Avenue, Hilton, Pietermaritzburg, 3201, South Africa
  • J Streatfield Jeffares & Green (Pty) Ltd, 6 Pin Oak Avenue, Hilton, Pietermaritzburg, 3201, South Africa
  • RP Gray Jeffares & Green (Pty) Ltd, 6 Pin Oak Avenue, Hilton, Pietermaritzburg, 3201, South Africa
  • EGM Oakes Jeffares & Green (Pty) Ltd, 6 Pin Oak Avenue, Hilton, Pietermaritzburg, 3201, South Africa

DOI:

https://doi.org/10.4314/wsa.v41i3.11

Keywords:

regional flood frequency analysis, KwaZulu-Natal

Abstract

Estimates of design floods are required for the design of hydraulic structures and to quantify the risk of failure of the structures. Many international studies have shown that design floods estimated using a regionalised method result in more reliable estimates of design floods than values computed from a single site or from other methods. A number of regional flood frequency analysis (RFFA) methods have been developed, which cover all or parts of South Africa. These include methods developed by Van Bladeren (1993), Mkhandi et al. (2000), Gorgens (2007) and Haile (2011). The performance of these methods has been assessed at selected flow-gauging sites in the province of KwaZulu-Natal (KZN), South Africa. It is recommended that the limitations of available flow records to estimate extreme flow events need to be urgently addressed. From the results for KZN the JPV method, with a regionalised GEV distribution with the veld zone regionalisation, generally gave the best performance when compared to design floods estimated from the annual maximum series extracted from the observed data. It is recommended that the performance of the various RFFA methods needs to be assessed at a national scale and that a more detailed regionalisation be used in the development of an updated RFFA method for South Africa.

Downloads

Download data is not yet available.

Metrics

Metrics Loading ...

Downloads

Published

2015-04-21

How to Cite

JC Smithers, J Streatfield, RP Gray, & EGM Oakes. (2015). Performance of regional flood frequency analysis methods in KwaZulu-Natal, South Africa. Water SA, 41(3 April). https://doi.org/10.4314/wsa.v41i3.11

Issue

Section

Research paper