Stormwater is water runoff following rain from developed land within townships. In undeveloped land 80–90 per cent of stormwater is absorbed by the environment; very little ends up as surface runoff into waterways, except during intense storms. However, in peri-urban townships like Aireys Inlet and Fairhaven, hard surfaces like roofs and roads significantly increase the amount of stormwater that reaches a waterway or ocean.
The Surf Coast Shire recently commissioned two stormwater studies for Aireys Inlet.
Aireys Inlet Stormwater Quality Assessment
This study analysed:
- the existing stormwater annualised pollutant loading,
- the effective reduction of this by way of existing water-quality treatment assets, and
- how this compares with current best practice in pollutant
The development of Aireys Inlet largely predates any industry standards regarding stormwater quality improvement and as such stormwater run-off pollutant loads do not meet best practice standards for 10 out of 11 catchments across Aireys Inlet.
Aireys Inlet has two treatment assets that were designed to reduce pollutant loads: Allen Noble Sanctuary and Narani Way. Allen Noble Sanctuary is meeting best practice benchmarks; Narani Way is not.
The study did not assess any harm to the environments of Painkalac Creek or Valley, beach foreshores or Sandy Gully beach caused by the stormwater quality issues.
Council noted that they plan to pursue funding opportunities to develop and construct viable stormwater quality improvement options (subject to stakeholder and community engagement and engineering design).
Link: Water_quality_Aireys_Anglesea_study.PDF
Aireys Inlet Stormwater Drainage Flood Study
The Stormwater Flood Study for Aireys Inlet provides a better understanding of the local stormwater network and flood risks within the township from stormwater run-off.
There were six locations identified as subject to flooding from stormwater.
There have been no changes made to planning schemes including flood overlays resulting from this study. The data will be used to plan for infrastructure upgrades, mitigation options and emergency planning.
Link: Stormwater_Flood_Study_LR.pdf
AIDA welcomes the studies and will be advocating for the following:
- encourage residents to reduce stormwater run-off from their properties
- seek funding to assess any harm to the environment resulting from the pollutant loads from
- consider mitigation options that not only improve stormwater quality and reduce flood risk but also reduce the quantity and velocity of stormwater that reaches the Painkalac Creek and Valley, beach foreshores and Sandy Gully beach. AIDA believes that, rather than increasing the capacity of hard infrastructure such as pipes and gutters, this is best achieved by:
- restoring roadside swales
- locating small bioretention assets within catchments rather than single larger assets at discharge points close to
We look forward to seeing a positive response from the shire on this issue.
Bron Ives & Jeanette Butler