Chapter 2 contains background information including a brief description of the study catchment
and its drainage system, details of previous flooding investigations, a summary of community
consultation undertaken as part of this present study (refer Appendix A for details), and a brief
history of flooding within the catchment.
Chapter 3 deals with the hydrology of the Lane Cove River and Swaines Creek catchments, and
describes the development of the RORB and DRAINS hydrologic models which were used to
generate discharge hydrographs for input to the hydraulic model.
Chapter 4 deals with the development of the TUFLOW hydraulic model which was used to
analyse flood behaviour in the study area.
Chapter 5 deals with the derivation of design discharge hydrographs, which involved the
determination of design storm rainfall depths over the catchments for a range of storm durations
and conversion of the rainfalls to discharge hydrographs.
Chapter 6 details the results of the hydraulic modelling of the design floods. Results are
presented as water surface profiles and plans showing indicative extents of inundation for a
range of design flood events up to and including the PMF. A provisional assessment of flood
hazard and hydraulic categorisation is also presented. (The assessment of flood hazard
according to velocity and depth of floodwaters is necessarily “provisional”, pending a more
detailed assessment which includes other flood related criteria, to be undertaken during the future
FRMS.) The results of various sensitivity studies undertaken using the TUFLOW model are also
presented, including the effects of changes in hydraulic roughness, partial blockage of the piped
stormwater system, and potential increases in rainfall intensities and sea levels due to future
climate change. This chapter also deals with the selection of Interim FPL’s for the study area.
Chapter 7 contains a list of references.
Chapter 8 contains a list of flood-related terminology that is relevant to the scope of the study.
Appendix A provides details of the collection of historic flood data and describes the testing of
the hydrologic and hydraulic models.
Figures referred to in both the main report and the appendices are bound in a separate volume of
the report (refer Volume 2).
