Concrete rings alternative storm water attenuation!

[Andehh]

Builder has come back with the cost of a 2400 x 2400 (approx) concrete ring attenuation tank under our driveway, saying the cost is now 3x his estimate when we started the build.

 

He is asking the architects for options, and I fear they will just shrug us off onto plastic crates.

 

I don't like the idea of these being sunk under our driveway for future debris build up & not being user serviceable, even with a catch tank further up stream.

 

Has anyone come across anything else that is worth exploring? Thanks

[PeterW]

Crates are a good option and to be honest with catch pits and filters you’ll not get it filling up with rubbish. 
 

How have they calculated attenuation as that’s a very big tank - is the plan for it to soak away as you’ll be at 3m deep minimum with a 2.4m deep tank to get the coverage over the top for a driveway

 

[Mr Punter]

I remember an earlier post regarding water under your slab and clay soil.  We careful with creating deep holes / tanks as they may just fill with water.

[joe90]

Yes when my BCO talked about a soak away fir my build I told him it would never drain as we are on solid yellow clay so he just let me pipe it to a ditch (that would carry the water away eventually anyway).

[Temp]

We put in a fiberglass rainwater recycling tank with the overflow going into a ditch. Handy for watering the garden. It has a debris filter up stream but still gets a fair amount of silt in the tank. Water comes out a bit brown. 

 

 

[Dave Jones]

crates work fine with upstream sediment catchers.