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Groundwork & Foundations

Do soakaways silt up eventually?

4 Answers from MyBuilder Groundworkers

Best Answer

Old ones, generally yes, the rate at which they do so depending largely on soil type and how well capped the soakaway was when installed. Even if a silt trap is installed the sides of the pit will eventually degrade. Newer soakaways have larger empty chambers, dont use hardcore/gravel pits and therefore dont silt up as fast. Another alternative is the 'swale' - an on contour ditch which can be turf lined / banks planted to hold topsoil. Swales act to direct rainwater runoff into subsoil and can therefore offset the need for summer garden irrigation. Swales should only be used in the right setting and are not recommend on heavy clay without proper overflow management.


Answered 28th Feb 2011

Yes soakaways do silt up eventually, if not constructed to the right size.
A lot depends on the type of ground, drainage isnt so good in clay.
They need to be constructed of the right size, right materials.


Answered 28th Feb 2011

Yes thay can but you can
overcome this by building a silt trap on the pipe line before the soak away


Answered 28th Feb 2011

Soakaways will eventually silt up. The rate of this silting depends on several factor but principally the following
The type of soil: In sandy soils particles will migrate with water to fill voids
in the soakaway.
The volume of water being put into the soakaway: If a soakaway can't handle the water quickly enough then it will silt up at the bottom and eventually the sides will collapse.
The solution rests in the construction
Use clean aggregate
Build in an overflow pipe if possible
Wrap the entire soakaway in a permeable material - allowing
water in and out but stopping soil entry.


Answered 1st Mar 2011

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