The study area is located within the Wollongong City Council Local Government Area (LGA) and incorporates Slacky, Tramway, Woodlands, Hewitts and Thomas Gibson Creeks. The combined catchment is approximately 7.5km2 and incorporates the northern Wollongong suburbs of Bulli and Thirroul. The catchment extends from the Illawarra Escarpment in the west, discharging into the Thirroul and Sandon Point Beaches in the east.

Following the completion of the 2015 Flood Study Review, Council developed a revised Conduit Blockage Policy in 2016. The 2015 Flood Study Review was based on Council’s previous Conduit Blockage Policy (2002) as documented in Council’s 2009 Development Control Plan.

This report provides an addendum to the 2015 Flood Study Review and outlines the revised design flood behaviour considering Council’s Revised blockage policy, in addition to catchment changes since 2015 and recommendations coming out of review of the models.