Farm Ireland

Wednesday 24 April 2019

Eoin's already reaping benefits of changing outdated drain system

Eoin Toohey, from Moneygall, Co Offaly, bought just over 20 ac in 2008, that had previously been rented out for over 20 years. The land had received little or no investment in that time, and the remnants of a drainage system were over 30 years old.

The land repeatedly flooded and was often waterlogged, even though he had made a few attempts at draining the land by putting in a long open drain. This was only a partial success, and after failing to successfully utilise this land in 2012, Eoin decided to drain it properly.

What process did he follow to identify the drainage system to be used?

He started to research his options, and was helped substantially by a conversation with Tim Gleeson and then Pat Tuohy of Teagasc.

He became aware that he needed to get down to the moving layer, and drain the soil from the bottom up, rather than from the top down having used only shallow drains in the past.

In the Christmas of 2012 Eoin dug a few test pits up to 3m deep. There was a peaty layer 5-6 inches deep at the top, then a blue marle that was 5-6ft deep in places. Springs were noticeably bubbling up at 5ft and finally there was a sandy gravel layer at around 2m deep.

Eoin previously hadn't had the confidence to dig so deep and was working with surface water rather than springs that were causing the problem. Pat Tuohy outlined that to effectively deal with the springs he needed to lower the water table.

What work has Eoin done to date?

Also Read

Eoin started the drainage process by digging open drains in March. He started at the lowest point in the field in order to get the greatest fall, and he went as deep as possible through the wettest part of the field.

Close to 400m of open drains have been installed to date, at a 33-degree fall. These were dug to an average depth of 2.5m.

The spoil is currently sitting against the drain, as the weather has turned since digging, but Eoin is hoping to grade the peaty soil over the field to improve its contour once the weather and growth improves.

Since digging the drains Eoin has observed a substantial volume of water moving in the drain and feels this would equate to 30-40l an hour leaving land.


The field has become substantially drier, although he is aware that the weather has been drier than in 2012. Even so, the drainage work has allowed him to roll the land, which he never managed before.

There are still a few wet patches and Eoin's plan is to put in deep 2m drains in the gravel layer using 4-6in drainage pipe.

This will involve putting around 6in of stone under and 2-3ft of stone on top of the pipe.

These drains will act as collector drains that will facilitate the use of gravel mole drains which will be run through the wet spots later on in the year.

The whole drainage procress will take several stages to implement properly and Eoin estimates the cost of the work will amount to around €20,000 for the 16ac of land being drained.

Irish Independent