Land drain for driveway - Can a land drain do these 2 things?

[digger]

Hi Tony
just registered; fantastic site. Am about to embark on laying a land drain alongside my driveway. Want the drain to do 2 things; 1.carry away surface water collected in an ACO drive drain as runoff from the asphalt drive & take it 15 metres to discharge into an inspection hole; 2. along the proposed course of the drain, which is at the base of a 3 ft high rock wall there's a lot of water that comes out of the banked ground above & in heavy rain can lie to a depth of 2 inches for several days - I want the drain to collect this surface water & carry it to the inspection hole also.I was going to use the collector drain method you suggest. Does this sound like it could work? Also in the collector drain diagram I wanted to know what material should be used for the "pipe bedding"?It's a combined surface & foul drainage system we have & I'm a bit worried about the amount of silt that mayenter the septic tank. Can you just incorporate a U bend just before the inspection hole to keep back the smells?
all best
Digger

[Tony McC]

In theory, there's no problem in what you propose, but you need to have some idea of the maximum potential inflow to determine whether a typical 80mm perforated pipe would be sufficient or whether you'd need a 100 or even a 150mm dia pipe.

Pipe bedding is typically a 10mm clean gravel but NOT limestone, chalk or any other calciferous material (such as crushed concrete).

An odour trap (and possibly a silt trap) are essential if you plan to connect to a combined or foul sewer. An S-trap is normally used (although it's almost identical to what you might call a U-bend).

[digger]

Thanks Tony
one last question. On the diagram for the collector drain you have the infill around the drain as being 60mm - 10mm material. Is that correct or should it be 60mm - 100mm?

[flowjoe]

It is normally bad practice to run storm water through a septic tank as you cannot calculate volume, to much water passing through the tank can affect the enzyme/bacteria or carry waste and fibres through the settlement tanks (even with dip pipes/baffles fitted) that then clog filter systems and soak-aways, or worse pollute the river/brook at outfall.

If possible keep the two systems separate and bring then together on the outlet of the tank.

[Tony McC]

Is all this discharging into a spetic tank? If so, as Joe says, it then becomes a very, very bad idea. I just assumed your term "inspection hole" was meant to refer to a sewer manhole - did you mean a septic tank??

Anyway, for the infill material, that is indeed 63-10mm material, as explained in the grading table below the x-section drawing.