what does this drain do?

[MattTaylot]

hi Tony,

guess who again.

Thank goodness this is the last day of the weekend. Unfortunately, the excavation will not be done today (even though we will have filled a 15 cubic yard skip -- how this happened when there is only about 25 or so square metres and we're only going down 200-300mm, I'll never know).

Anyway, yesterday we came across a drain that looks as though it is just for surface water. Top of the gully intact and cemented shape beside it that has the form of the bottom of a downpipe off a gutter (or something like that).

Only two things:
(1) this whole thing was buried under about 100mm or so of cement
(2) we followed the pipe, a metal one, that leads out of it and it continues past where the sewage goes behind my house. The sewage runs behind the house parallel to the back wall about 1 metre or so into the garden away from the wall.

The pipe from this old gully, etc., runs perpendicular to that back wall (away from it) passes over the sewage pipe that I mentioned in the previous paragraph (not that I dug down as far as the sewage) and then continues away from the house for at least another metre after that.

At that point we stopped digging (too much other digging to do).

I'm assuming that it was a surface water drain that just drains into the soil somewhere. But which is no longer used (I figured all the concrete on top put an end to that).

Does that make sense?

With a metal pipe, any ideas of its age?

thanks again, not it's back to the final day (this week :( ) of digging and carrying and...

Matt

[84-1093879891]

15 cu yd skip? I doubt it - most are 7 cu yd or 5m3 and you can only get approx 4.5m3 of excavated material into them. A skip wagon wouldn't be capable of lifting 15 cu yd of excavated clay/soil/concrete, and it certainly wouldn't be able to carry it on the roads. As a guide, an 8-wheeler wagon, carrying a full 20T load holds about 9m3

Anyway - the mystery pipe. It sounds like a Cast Iron feed pipe to a soakaway, probably constructed from buts and bats of leftovers, possibly by a previous homeowner, as CI is not a cheap option for drainage.

Is it still functional?