Commercial development projects need to take care of stormwater with a detention tank, a retention system or both. Discover the difference between the two.
Developing a commercial property in Australia comes with a number of requirements. One of these is to find and implement a suitable solution for managing stormwater run-off.
Basically speaking, if your development is set to replace the earth with concrete, you need somewhere for heavy rain to go, otherwise, the local area is at risk of being flooded.
There are different options for the stormwater management system you choose, depending on the way you can use excess water. One is stormwater retention, the other is stormwater detention.
Even though there is very little difference between the words retention and detention, when it comes to stormwater management, the two are definitely not the same.
Stormwater retention systems/water harvesting
When you install a stormwater retention system, it is with the intention of collecting and storing water for reuse. The same way you would with a house’s grey water, the water goes into a tank and is then reused for things like flushing toilets or washing vehicles. The water isn’t fit for consumption, but if you can find a way to use it around the property, choosing a stormwater retention system makes sense.
This water harvesting solution is environmentally friendly and can help to reduce the operating costs of operating a commercial building. At Australian Tanks, we have installed stormwater retention solutions on sites including:
- Defence sites at Enoggera, Oakey, Canungra and Greenbank, Richmond NSW, Eclipse Hill WA.
- Fuel stations and commercial developments
- McDonald’s stores throughout Queensland and New South Wales
Stormwater Detention Tanks – OSD
Stormwater detention refers to the process of temporarily holding stormwater and slowly releasing it back into the public stormwater system at a controlled rate. This is to ensure that floodwater doesn’t overwhelm the environment.
The acronym you will come across is OSD, which either stands for Onsite Stormwater Detention or On-Site Detention.
The rules for the types of buildings that require stormwater detention depend on the state where you are based. For more specific regulations consult your local council, however, the general rule of thumb for properties requiring OSD across Queensland, New South Wales, Victoria and the rest of Australia includes (as shared by Sydney Water):
- all commercial, industrial and special use (for example, community, education, recreational) buildings or structures.
- townhouses, villas, home units or other strata subdivisions. These may use a single OSD system for the total site area if it’s located on common property and the body corporate is responsible for maintenance.
- dual occupancy lots. Each lot within the dual occupancy must have its own OSD system. Each individual lot owner is responsible for maintenance.
- sealed sporting facilities (for example tennis, basketball courts).
Which type of stormwater tank is right for your development?
Stormwater retention systems and stormwater detention tanks can both be installed as an underground solution. You cannot put a multi-storey building on top of an underground water tank, so they usually sit adjacent to a building or under the car park.
The stormwater management system you choose will depend on the needs and purpose of your development. If you are able to reuse stormwater, it will make sense to choose a retention system. In other cases, an OSD may be more appropriate. At times, the solution may involve a mix of stormwater retention systems and stormwater detention tanks.
The size of the stormwater detention tank or stormwater retention system you require will also depend on the size of your project. Tanks start from 100,000 – 200,000 litres and there are models that can hold up to 800,000 or even 1 – 2 million litres of water.
There are more than basic tanks involved with stormwater management. Things like filtration also come into play, which is why your project needs tanks that are compatible with all the different filtration systems on the market, or to find a ‘turnkey’ solution. Underground tanks also need to connect with existing plumbing infrastructure at the right level. It makes sense to look for a tank supplier that keeps both of the above in mind.
Choosing the right stormwater management system will depend on the needs of your project, as well as local regulations. Visit our Engineers Hub to view the specifications and capacity of our stormwater tanks, or contact Australian Tanks to find out more.
