Clearing a drain

[michaelb]

I have 2 drains in a driveway. In heavy rain they cannot drain fast enough. Each is about 250mm dia by 500mm deep. In the wall there is a sort of baffled slot which is full of vegetation and silt, like grass or small roots. I cannot get a hand in to remove much, but they do drain OK eventually. They are in the drive at least 7m from the edge and any vegetation.
Is there anything that will eat the crud - chemical, termites, magic, as I don't want to dig up the drive yet.

Thanks
Michael

[84-1093879891]

What you term 'drains' are actually "Gullies". If they are blocked with vegetation and silt, then you could try a combination of a power/jet washer to loosen the silt and blast away any vegetation along with a drain cleaning fluid (glorified bleach) which will eat away at any organic matter. Once cleared, regular cleaning with the jet washer should ensure the gullies keep functioning with no further problems.

Your descriptiion of 'baffle plates' interests me and makes me wonder whether there are silt/mud buckets fitted to the gullies. These are a form of perforated steel liner that sits inside the pot and can be lifted out to aid cleaning. Is this a possibility?

[michaelb]

That was quick, many thanks. I'll try pressure jet and also use bleach to eat at the vegetation.
One gully is square and indeed has a removeable bucket/tray. The only way out for water is one semicircular hole at half depth that points upwards (trap?). It is difficult to get more than a couple of fingers in, and I would have expected a bigger hole (75 or 100mm). The other is a plastic cylinder about 150mm dia. This seems to be a liner inside another cylinder and the only way out for water is the small gap where the inner liner stops an inch or so above the bottom of the hole floor. This gap is full of veg.

Thanks
Michael