Conclusions
The objective of the study was to undertake a preliminary investigation to identify and map sub-catchments and major overland flow paths within urban areas of the Liverpool LGA. This was
achieved through the development of a flood model of the study area, underpinned by the detailed
representation of catchment topography defined by available LiDAR data acquired in 2013.
The key findings and recommendations of the study are summarised hereunder:
- The developed model compares favourably with the outputs of the detailed modelling
undertaken in the Stage 2 and Stage 3 studies, confirming the suitability of the model for
assessing the overland flood risk;
- A number of urban areas have been developed subsequent to the acquisition of the LiDAR data
in 2013. In the absence of detailed post-development topography for these areas, the modelling
has not been updated to reflect the recent development. These areas include parts of:
Elizabeth Hills; Middleton Grange; and Prestons
- The remaining areas show some overland flooding
risk to existing areas. Much of this overland
flooding affectation is in local sag point or depressions which would typically be drained via local stormwater drainage provisions. Nevertheless, the Stage 4 overland flow mapping represents a
fully blocked condition in the urban drainage network which may warrant further investigation.
The key areas of affectation are parts of :
Cartwright; North Liverpool; Warwick Farm; and Wattle Grove
- The established flood models can form the basis for future assessment of flood risk in the catchment. The incorporation of the stormwater drainage network in future detailed studies will
refine the models and provide an improved representation of overland flooding
- Based on the identification of the key areas of potential overland flood risk, the study
recommends the following prioritisation of catchment areas for further detailed investigation: Locality/Sub-catchment Priority Ranking
Warwick Farm 1; Middleton Grange 2; Elizabeth Hills 3; Wattle Grove 4; Liverpool North 5; Cartwright 6; Prestons 7
