Percolation Test trial hole ponding

AlertKevin

Hi,

We dug the percolation holes at the weekend. Very clayey and grey soil. The P and T holes looked fine. The issue is with the trial hole, as we dug and reached the 2 metre depth water started filling the hole around 2 feet. I went back the following day and it's over half full.

The land is not ours and we knew it was bogging with natural drains for water near the ditch.

I'm worried about this land and problems that may arise.

Is the trial hole being filled with water an issue?
Could there be more issues with the land If we put a system in for percolation and build a house?

There are a lot of mixed information so not sure to precede with the planning or not.

Thanks

sydthebeat

AlertKevin wrote: »

Hi,

We dug the percolation holes at the weekend. Very clayey and grey soil. The P and T holes looked fine. The issue is with the trial hole, as we dug and reached the 2 metre depth water started filling the hole around 2 feet. I went back the following day and it's over half full.

The land is not ours and we knew it was bogging with natural drains for water near the ditch.

I'm worried about this land and problems that may arise.

Is the trial hole being filled with water an issue?
Could there be more issues with the land If we put a system in for percolation and build a house?

There are a lot of mixed information so not sure to precede with the planning or not.

Thanks

yes is the short answer

the long answer has more to do with exactly what depth in the hole the water table is at.

they generally require a min of 1.2 m of good soil between the bottom of the percolation pipes and the water table level.

there will be evidence of the highest point of the water table anyway, even if there was no water in the hole at the time of testing.

Johnnyhpipe

You can sometimes explore a raised percolation area if the tests fail. However you'd need input from design engineer who will likely further consult a specialist designer. I've done it before so might not be the end of the line for you.

Edit - to clarify...you still need some degree of soakage for this to work. If you're getting nothing at all then its not a realistic option.

Metric Tensor

Also worth asking the question that if the ground water level is approx. 1.4m from the surface in mid-April where is it going to be in January!

hatchman

Metric Tensor wrote:

Also worth asking the question that if the ground water level is approx. 1.4m from the surface in mid-April where is it going to be in January!

I believe this time of year is when the water table is typically at its highest so January would probably be a slightly better time than now to do test ..

sydthebeat

hatchman wrote: »

I believe this time of year is when the water table is typically at its highest so January would probably be a slightly better time than now to do test ..

nope.

as i said above... there is evidence in the ground of the highest point of the water table. its called mottling.

therefore the only advantage about doing the test in dryer months is that you run less risk of rainwater flowing into the test holes.

hatchman

sydthebeat wrote:

therefore the only advantage about doing the test in dryer months is that you run less risk of rainwater flowing into the test holes.

So a test performed during a dry period will give different results to when there is a lot rain ?

sydthebeat

hatchman wrote: »

So a test performed during a dry period will give different results to when there is a lot rain ?

If the rain is flowing from the ground into the hole, then yes.
And unfortunately there's no way to account for this in the results.

Metric Tensor

hatchman wrote: »

I believe this time of year is when the water table is typically at its highest so January would probably be a slightly better time than now to do test ..

Could be. I know September is usually considered the lowest.