I’ve often felt sorry for the poor street trees that are surrounded by asphalt and concrete, and I’ve wondered how they get enough to drink with so much impermeable paving around them.
A while ago I posted about the value of street trees in our cities [no brainer really], now along comes this cool design solution out of NYC that shines even more value on the idea. It’s the result of collaboration between design professionals, planning / governing authorities, and residents, and is one outcome of the USD$1.6billion that has been pledged by New York City to the Green Infrastructure Plan [check out the site – it’s a treasure trove of cool initiatives around water management]. This bioswale is a street retrofit solution that;
- increases groundwater re-charge & reduces stormwater volume;
- cleans stormwater and reduces waterway pollution;
- increases vegetation, habitat and nature outlook;
- creates local shade and cooling [reduces heat island effect];
- filters out dust & buffers wind;
- increases real estate value.
It might sound trivial, but the inlet and outlet integrated with the existing gutter is just cleverness – it allows volumes of stormwater to take a significant detour into the bioswale, which is effectively a deep soakage pit filled with gravel and lined with geotextile… so it’s a great retrofit idea. The example above is cut into the existing footpath, but the same applies when cutting into the roadway instead.
There are many variations on this theme too – soft kerbs, swales instead of extruded gutters… there is an effective solution for each type of street.
Next time you take a walk [or drive] through your own city, imagine where such bioswales could be added, and think about how you might build the justification to have some installed. And be sure to spend some time browsing NYC’s Green Infrastructure Plan web site – they’re really getting on with things.
Personally I really think I need to get to NYC to do some ground-truthing.