Forum topic: The reconfigured Palmers Green Triangle

Love it. Have driven and cycled, works excellently for both, massive improvement all round. Can't wait to EMH is completely finished and enforced.

Yes, good to see a tree back on the Triangle. It does look spindly at the moment, but I hope it will flourish in the new forest that has been created - I counted 16 other vertical objects around it of various heights. New street clutter or what?

While I largely welcome the work that has been done on the Triangle, I can't imagine why anyone would want to sit in the middle of what is in effect a large traffic island. Will face masks be provided? In the mean time, could not the rather awkwardly placed Christmas tree, with its ugly 'skirt' of advertising hoardings, be sited there?

By the way, excuse my ignorance, but what is a 'rain garden'?

Here's one definition of rain garden: "A rain garden is a planted depression or a hole that allows rainwater runoff from impervious urban areas, like roofs, driveways, walkways, parking lots, and compacted lawn areas, the opportunity to be absorbed." Given the Triangle's history, and all the works that were necessary to create the new junction, I can well understand the need for one.

Personally I haven't stopped to enjoy the new island; just cycled through or paused at the traffic lights. As far as its visual appearance is concerned I'll wait till after Christmas to take a good look.

Rain gardens - even small ones like on the Triangle - are small parts of a big scheme to improve the quality of the water in streams and rivers - the Lea and the Thames = and reduce flooding. One little rain garden doesn't have much impact, but combined with many others it has a noticeable effect.

Rain gardens are one form of "sustainable drainage system" or SuDS.

So if there is sustainable drainage, then logically there must be unsustainable forms of drainage. Unfortunately, there's a lot of them around. Gutters and drains in roads, for example, tarmaced over gardens. When it rains heavily on impermeable surfaces, large quantities of water rush along the gutters and go down the drains. That water, full of impurities from the road surface, such as heavy metals, ends up flowing into streams - locally, the Pymmes Brook, thence into the Lea, and is damaging to flora and fauna (or may encourage some undesirable flora and fauna at the expense of more desirable ones).

The idea of sustainable drainage is to get water to soak into the ground and/or be slowed down and filtered by vegetation and "wetlands". The net result is that water flows more evenly into the rivers istead of in spurts and less water rushes down tarmaced hills and causes flooding at the bottom.

The above is terribly oversimplified. The page below explains it much better than I ever could and has some pictures:

www.thames21.org.uk/sustainable-drainage-systems/

Good examples of SuDS round here are in Grovelands Park, Houndsden Spinney (a great place for wild garlic!) and, above all, Firs Farm.