Sankey Street, Hawley Stormwater Improvements Report
Since June 2020, several properties in Sankey Street and Hawley Esplanade have experienced stormwater inundation. The most recent significant event occurred on the night of 28 February 2023 and 1 March 2023 which was likely to have been between a 1%AEP and a 0.2% AEP rainfall event which is an infrequent/rare event.
Council has a capital budget allocation to address this issue.
GHD has assessed the hydraulic performance of the Sankey Street Stormwater Catchment using the ARR (Australian Rainfall and Runoff) 2019 guidelines and the computer program InfoWorks ICM for the minor (10% AEP) and major (1% AEP) design storm events. The analysis indicated widespread flooding/inundation to properties in Sankey Street with the existing detention basin spilling for both design events.
At the March 2024 Council endorse the following recommendations:
1. Note that an application for Disaster Resilience Funding to assist with the project is being prepared; and
2. Receive the report prepared by GHD titled Sankey Street, Hawley Stormwater Improvements dated 02 February 2024; and
3. Acknowledge that kerb and channel has been identified as the preferred means to better contain overland flow within the road reservation;
4. An update and copy of the report be placed on Councils website and this be communicated with residents in both Sankey Street and Arthur Place; and
5. Council officers have the work undertaken by GHD furthered on the following basis:
a. That kerb and channel be installed in Sankey Street to form an overland flow path from the western end towards the foreshore and will have fall across Hawley Esplanade (either raised sag in Sankey Street or localised lowering of Hawley Esplanade;
b. That the existing detention basin be retained and potentially receive minor modifications as determined necessary; and
c. That 1% AEP (Annual Exceedance Probability) climate change runoff that cannot be managed within the existing detention basin, the existing pipework in Sankey Street or the proposed overland flow path between kerbs in Sankey Street be catered for within an upgraded (either duplicate or upsized) pipework within Sankey Street to the foreshore.