Mosman has 14 Stormwater Quality Improvement Devices (SQIDs) operating in five different catchments removing pollutants from stormwater before it reaches the waters of Sydney Harbour. Stormwater from over 60 per cent of Mosman’s catchments is now treated by these SQIDs. Under the CEC schedule of works, SQIDs will be installed in the majority of untreated catchments by 2005. They are currently installed in the Balmoral Beach, Sirius Cove, Quakers Hat Bay, Avenue Road and Mosman Bay catchments.
Assisting in the capture and removal of gross pollutants from stormwater runoff, SQIDs greatly improve the quality of receiving waters. Monitoring projects are currently underway to measure exactly what effect SQIDs have on other water quality indicators and pollutants. In the 2002/2003 financial year, the following was achieved.
- Cleaning and maintenance of the 14 SQIDs occurred 31 times.
- The number of SQID cleanouts was reduced by a total of 20 cleanouts from the previous financial year.
- A total of 53.66 tonnes of gross pollutants were removed from the SQIDs.
- The gross pollutant composition was calculated as 81 per cent organic material, 11 per cent sediment, and eight per cent litter.
- The amount of gross pollutants captured is about 60 tonnes less than what was captured in the previous financial year.
Although less material has been collected, it doesn’t necessarily mean that the SQIDs are not performing as well as previous years. Reduced pollutant loads captured by the SQIDs can be equated with fewer pollutants in the catchments through greater awareness education /community response. In addition, with the recent prolonged drought there has been minimal dry weather stormwater flow. As a result, over this period gross pollutants in the catchment were not collected by stormwater runoff and directed to the SQIDS as would usually be the case.
