The ins and outs of cleaning and freeing up blocked drains

Daniel Hession looks at a number of solutions for a problem that is on the rise across Ireland

IN Ireland’s wet climate, floods in fields and paddocks are a regular sight. Wet soils pose many problems for farmers: Later grazing start dates, lower grass growth levels, and grazing animals and machinery cutting poorly drained ground.

Measures are taken to drain these soils, like sub soiling and laying down closed pipe drains and open drains.

The open drains can easily be cleaned with a digger — but the miles and miles of closed pipe drains on Irish farms can’t be cleaned out. Over the years, these pipes become blocked with clay and silt. Eventually they can completely block, and no longer serve their purpose.

New methods of drainage and different materials for pipes or for placing around pipes have been tried, but overall, the many major technological advances in agriculture haven’t extended into the area of drainage.

When the soil starts to get very wet a few years after drainage pipes are laid, you can probably blame blocked pipes. This problem leaves the landowner with few options. Either put new pipes in place beside the existing pipes, or try to dig up the existing pipes and put new pipes in their place. This can be a nightmare operation.

It is also very expensive, the costs of new pipes, stones, and work carried out have to be contemplated. Is it worth it, if the new pipes will end up the same way in another couple of years?

But street pipe drains can be cleaned, so why not field pipe drains?

Ireland has turned for the answer to the Netherlands, where about 27% of the land is below sea level, and drainage plays a vital role.

O’Donovan Agri Environmental Services, based in Ballincollig, Co Cork, started importing Homburg land drain cleaners from the Netherlands about three years ago.

These land drain cleaners are designed to clear even the worst blocked drains. First designed in the Netherlands about 16 years ago, the drain cleaners needed modification for Irish conditions, in order to achieve the best performance. Now they are ideally suited to Irish conditions, and have been busy at work on farms.

There are Mini, Junior, Delta, and Senior models. A new model is almost ready, called Hurricane, which has wireless remote control.

All models carry out the same function, and use the same method, differing only in how the guide arms and hoses are adjusted, either manually by winches, or hydraulically.

The Junior model is aimed at the farmer market. It is manually operated but capable of the same output as the other models. It requires two or more people to operate it effectively. Junior comes with hydraulic roll on/roll off flushing hose, continuously adjustable speed control, height adjustment by winch, and manual length and horizontal adjustment.

Delta has all the same features, but comes with a hydraulic foldable guide arm, adjustable in length. There is also the option of electric/hydraulic operation.

Senior is ideally suited for contractors and businesses specialising in drain maintenance services. It has many hydraulic functions for ease of operation, including an automatic hose guide, and a manometer for reading hose input pressure. A lighting set is optional.

Each model is PTO-operated on a tractor three-point linkage, and has the same operational output of 70-80 litres per minute. Hydraulic oil flow rate required varies between models, the lengths of hosing supplied are the same for each machine. Machine weight also varies.

So how exactly do they work? I spoke to John O’Donovan to learn how the drain cleaner operates. “It’s a low-pressure, high-volume principle,” John explained.

Other approaches to drain cleaning involve high pressure, which often makes the blockage worse (old, brittle plastic pipes can shatter under high water pressure).

The machine’s 300m strengthened flushing hose is transported up the drainage pipe under pressure on four large rubber tracked wheels. Hose nozzle types and nozzle cages are selected according to pipe type (plastic, clay, large concrete etc). At the front of the nozzle, a cylindrical ring of water jets faces forward and upwards at an angle designed to remove dirt from the inner wall of the pipe and clear the pipe pores — but at the same time, not flush the dirt forward further into the pipe. At the rear of the nozzle is another ring of jets which flush dirt and& sediment back towards the mouth of the drain.

John explained that a major cause of blocked pipes is metal build-up in the pipes, especially iron deposits. As early as two or three years after laying drainage pipes, sediment from the unwashed stone that is put around the pipes to aid drainage can build up in the drainage pipes, causing blockages.

Plant debris, or vegetation can also block pipes.

For the Dutch drain cleaners, a strong tractor is not required. Anything from 70 horse power up is sufficient. A hydraulic oil flow rate of 10-15 litres per minute is needed. The heaviest of these drain cleaners is only 860kg, which includes the weight of water in the machine. Ground conditions do not have to be excellent, but the drier the land, the less damage caused.

John O’Donovan explained to me that reduced compaction was a key concern when designing the machines.

Water is the essential requirement. Between 50 and 70 litres per minute of water are pumped, therefore a good supply is essential. If cleaning of drains takes place beside a river or stream, water can be sucked from there and used by the machine. If a river or stream is not nearby, water must be drawn to the site of operation.

All drain blockages are not the same. Cleaning 200m per hour is achievable, but John said that 800m per day is average, allowing for blockages that slow the operation.

Having grasped the specifications of the cleaners, and the principle of operation, I asked what’s involved in operating them, and what problems one might encounter when using the cleaners.

John assured me that the problems encountered to date have not been due to the machine. Often, the landowner has put down drainage pipes but didn’t mark where the pipes are. That holds up cleaning, because the openings of the drainage pipes can’t be found.

It is claimed that the only blockage the Homburg cleaners can’t clear is a collapsed pipe. But they can pinpoint the problem area, so that the pipe is dug up and fixed. A tracking system can be fitted, which pinpoints to within one third of a metre the location of a blockage that can’t be cleared. This saves a lot of unnecessary digging, land damage and cost.

There is huge interest in the cleaners. John says they arrived in Ireland at the right time. “We are experiencing very high rainfall in all parts of the country, and farmers wish to do something about it.” He says the drain cleaners will help expanding farmers.

“Land is the limiting input, not much more is available, so enhance existing land,” he advises.

I was quiet surprised when John revealed that the Junior model starts from only €11,000 plus Vat. Considering the often unseen or unaccounted costs of blocked drains, and the costs associated with rectifying the problem, a drain cleaner could be a worthwhile purchase.

There are virtually no maintenance costs. The key maintenance step is to store the cleaner appropriately to prevent frost damage (as for sprayers). The nozzle and the hose are the only wearing parts.

Or you can hire a contractor for drain cleaning. One such service is provided by Crangle Environmental Services in west Cork.

If you are planning any land drainage work this summer, consider having existing drains cleaned.

And if you are putting in new drains, use a pipe drain system. John O’Donovan highlight a problem that Teagasc is reporting to him. Farmers are putting down drains without pipes. Digging drains and filling them with stone is a common practice — but when the stone gets blocked, there is nothing that can be done.

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