Need advice about land drainage and where the water is to go

[ademco]

Hello there, have posted on the building forum about our 105 ft soil retaining wall around our extention before. We live on a slope in a rural location and have built an extention to our cottage on the top side of the slope, which involved removing many hundreds of tonns of soil. We have just built a soil retaining wall some 105ft long around the extention-big extention. We are laying drainage piping behind the retaining wall and at the bottom of the extention wall as per building regs. But they did not say where the water is to go. Our builder at the time of the build said to dig a 1x1m hole down the garden and fill it with hardcore for the water to soak away into. Our garden has a brook at the bottom of it so any water would end up there anyway and our soil is heavy clay so a soakaway is a no go. Can we not just lay the pipes so they go into the brook. Any thoughts on this matter would be most helpfull.

 

[Thermo]

practically yes, but you may need to check with with the nra as they may say no!

 

[Bankrupt]

I'd put a large bet that if you ask the question the NRA will say no. Even if the soil is very heavy a suitably sized soakaway should do the trick.

 

[Thermo]

in heavy clay? how big a soakaway would you suggest?

 

[Bankrupt]

in heavy clay? how big a soakaway would you suggest?

What worst case water flow rate into the soakaway do you want me to base my calculations on ? Or what area ( m2 ) are you collecting water from ? - If I knew that i can calculate the flow you'd get during a typical English deluge from the skies ! .

Yes - amazingly even heavy clay will soak up water ! .

 

[Thermo]

yes i know it will, but how big will it need to be to efficently deal with the water? If there is a route out for the water to take then its better than having it sitting in a clay swimming...sorry soakaway!