Last year I read a Council document that said Marrickville had reached capacity for the sewerage system. This is before the development of the expected new housing. Therefore it is understandable why Council is working hard with their sub-catchment plans, building rain gardens & devising other ways to manage & direct stormwater into the ground.

Yesterday I read an article about bioswales that are starting to pop up along the streets in New York City. The bioswales look like very attractive verge gardens with a street tree or two & surrounded by a short filigree wrought iron fence to protect the plants.

Instead of a verge garden that has limited abilities to catch & retain stormwater (though they are still way better than concrete), each NYC bioswale is 1.52-metres deep (five foot) & can absorb 7,570-litres (2,000-gallons) of water every time it rains.

They have disposed of adding a hole in the kerb for stormwater to enter. Instead, they have made it so the surface around the kerb directs stormwater to the swale. They have also left a large unkerbed entrance so that all the stormwater enters the swale.

Any stormwater that enters the ground rather than the drains saves money. In the case of NYC, the savings amount to billions of dollars. Stormwater that goes through the ground as nature planned, gets cleaned by the process before it enters rivers, streams & lakes or the groundwater system.

NYC’s sewerage infrastructure is similar to Marrickville Council’s in that it was built when the city/suburb was young. Stormwater that didn’t enter the ground was easily incorporated into the drains system. Now that hard surfaces & the population have increased, the system is working to full capacity.

NYC intends to build thousands of street side bioswales & expect to eventually have the most bioswales in the world.

The photos in the article show that they use a variety of plants, including flowering plants. Add thousands of bioswales to their Million Tree program, their pocket park projects, plus their green walls & green roofs & I think NYC will manage to provide a livable & attractive environment while adjusting to the raised temperatures caused by global warming.

There are 13 photos with this article. Some show beautiful bioswales on New York Streets, while other images show how the bioswales work. See – bit.ly/1jONtKM

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