Quantitative assessment of flood discharges and floodway failures through cross-cultivation of advancement in knowledge and traditional practices

Quantitative assessment of flood discharges and floodway failures through cross-cultivation of advancement in knowledge and traditional practices

Purpose – The 2011 and 2013 Queensland, Australia flood events caused massive infrastructure damage
for low-level stream crossings such as floodways and culverts in regional Queensland. Failures of newly built
floodways during the 2013 Queensland flood event in the Lockyer Valley Regional Council area raised
significant concerns with respect to floodway design practices adopted in Australia and attracted significant
research interest to enhance the resilience of floodways. Review of existing floodway design guidelines
indicates that floodway design process is closely related to hydraulic and hydrological aspects. However,
conducting a hydrological analysis is a challenging in rural areas, mainly owing to information scarcity.
Floodways in rural areas often require a simple and economical solution contrast to more detailed
hydrological analysis approaches adopted in urbanised areas. This paper aims to identify and apply the
rational method to estimate maximum flood discharges at selected floodway locations in the Lockyer Valley
Regional Council area. The paper further attempts to provide the first insight of flood characteristics during
the 2011 and 2013 Queensland flood events at three catchment outputs across the selected case study area. It
also highlights modern day challenges for practising engineers and researchers when estimating flood
characteristics in rural areas. The paper shows that cross-cultivation of advancement in engineering practices
and traditional approaches can promote quantitative approaches when assessing floodway damage in
regional areas.
Design/methodology/approach – The research identifies limitations when assessing flood impact in
rural regions in collaboration with experience from industry partners and authors themselves. The authors developed a framework to overcome those limitations arising from information scarcity to minimise the trial
and error design approaches utilised in the current design practices for floodways.
Findings – This paper developed a simple and effective hydrological method with minimum inputs. It also
provides an example on collating available but scattered resources and traditional method to quantitatively
assess flood discharges of a rural catchment in Australia. Flood discharges at three catchment outlets along
the Left-Hand Branch Road in the Lockyer Valley Region during both 2011 and 2013 Queensland flood events
are estimated for the first time. The findings highlight the impact of flood discharges and flooded period on
floodway failures.
Research limitations/implications – The current research is based on a selected case study area in
Australia. However, similar challenges are expected all across the world, due to the scarcity of rainfall and
flood measurement gauges.
Practical implications – Floodway designers can apply similar framework to estimate the flood
discharges instead of current practice of trial and error process. This will provide more scientific and reliable
estimation and assessment process.
Social implications – One of the social impacts identified in the broader research is the community
outrages and disagreement between floodway design engineers and the community. Following the developed
framework in the manuscript, design engineers will be able to justify their assumptions and design work.
Originality/value – The paper presents a novel framework on collating different and scattered
information towards estimating flood discharges in rural areas. The manuscript presents the first insights on
estimated flood discharges in the selected case study area during the 2011 and 2013 Queensland flood events.
This will enable further research to be performed in a quantitative manner rather than the present approach
of qualitative manner.

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