Mt Evelyn Sustainable Car Wash

…a good example of how numerous stakeholders can benefit at the same time as the local waterways.

The Mt Evelyn Carwash Stormwater Reuse project forms part of the Little Stringybark Creek research project. The aim of the project is primarily to reduce the amount of stormwater flowing to the creek while providing water treatment and returning a baseflow to the creek.

Having a high demand for water meant that the car wash was an ideal way to reduce the stormwater flowing to the creek while also providing a significant benefit to the operators of the car wash.

The stormwater harvesting system collects stormwater from a Council stormwater drain adjacent to the petrol station. It also collects water from the hardstand areas (roof and paving) of the petrol station site. The runoff from the hardstand areas flows via gravity to a tank located underneath the petrol station. The stormwater from the Council drain is diverted to a gross pollutant trap (GPT) and then to a pump well where the water is pumped to a separate set of tanks also located underneath the petrol station.

Water is extracted from these tanks and pumped through a treatment plant before it flows to a clean store tank and then to the car wash for re-use. The tank is made to leak water back to the Council stormwater drain (downstream of the system bypass) to mimic an environmental flow to the creek. This leak flows through a media filter to treat heavy metals and other pollutants.

Being a developed site, key consideration was given to the placement of the system components . The design ensured that the system was compact while still being easily maintainable. Collaboration between the car wash owners and Yarra Ranges Council was critical to ensure this system met all the objectives. Although the system will not be a Council asset, they realised the importance of projects like these and have helped with the construction supervision and allowed the GPT to be placed within Council land which they have also offered to maintain. The harvesting system will help reduce the loading on their drainage system in higher flow events which is a benefit for Council.

This project is a good example of how numerous stakeholders can benefit at the same time as the local waterways.