Inspecting flooded centre pivots

Centre pivot irrigation systems can be affected by flooding in a number of ways.

After floodwater has receded and it is safe, inspect the entire system. Any caught debris should indicate how high the floodwater rose. It is important to note any structural damage at this stage, as well as any soil erosion that may undermine the centre pivot.

You should also seek advice from a licensed electrician before repairing or using systems that have been submerged or affected by floodwater in any way.

If you will be making an insurance claim due to flooding, you should keep a record of any damage to the centre pivot (e.g. take photos). Before attempting any repairs, you should also talk to your authorised dealer to ensure you do not void your insurance or warranty.

Pat Daley from Daley Water Services, and corn and cotton grower Nathan Bradley, show how to:

  • inspect a centre pivot's mains control box
  • inspect a flooded centre pivot's sprinkler package
  • prevent damage to a centre pivot during a flood.

Mains control box

  • [Pat Daley from Daley Water Services]

    Today we are going to run through what we should do to check over a centre pivot in the case of flood-prone areas... and this is where we will start here at the mains. You want to just explain about the centre pivot and how many spans it is...

    [Nathan Bradley, cotton grower]

    Right, it's a Valley 10 span machine that covers 84 hectares. This is the main power source here. So we will turn the main power off to the machine and then that isolates all the power which runs down under the ground into the centre power into the control box so now that that's off, everything is safe to have a look at.

    [Pat Daley]

    That's good. Have you got any idea of where the debris may have come to?

    [Nathan Bradley]

    Well, the water obviously didn't go over the motor here, it went over the tops of the motors on the pivot. As you can see around us the creek came around and gouged out here luckily. There was water underneath the main power source here, so I think I probably should get an electrician out to check the power source before we go any further because water would have gone down the conduit here so that's probably the first thing that I will get checked out before running the machine.

Sprinkler package

Pat explains how to inspect the static plate, nozzle housing, adaptor and regulator of a centre pivot on corn and cotton grower Nathan Bradley's property.

  • [Pat Daley from Daley Water Services]

    So what we are looking at here is a typical situation where the debris has built up around the spray – this is a static type spray and they are very susceptible to these sort of blockages.

    If you did not go through and do some checks on all these sprays and try to run it like this then the debris, there is a good chance that the debris would not clear so it would have a big impact on the uniformity of the sprays and possibly be the cause of some wheel ruts forming because we are not getting the wetted footprint that we normally would achieve.

    So it is very important to go along – these sprinklers are relatively easy to pull apart – that is the static plate, clear the debris out of there.

    This is the nozzle housing, there is the nozzle there, so we go through and clear all this debris out of there. It is a good idea to check the nozzle as well to make sure there is nothing inside. Quite often being this low you might get insects and things up inside.

    Also the adaptor that that screws onto, most people stop at this point but it is a good idea to bring some spanners and undo this regulator. It is a good opportunity to check that there is no debris inside the regulator.

    Whilst the nozzle may be clear, if the regular is blocked it will have some effect on the operation of the sprinkler... so you see it goes back together relatively easy.

    There are some other types of sprays that have moving plates and they are in danger of any sediment build-up there grinding away at that moving plate. So any sprinkler at all I advise that you go through and clear the debris away from them after a flood event and check the inside as well. Don't assume that everything is going to be on the outside.

Preventing flood damage

Taking preventative measures before a flood can:

  • help you avoid costly repairs
  • save you plenty of work when cleaning up
  • ensure your centre pivot is back to normal operations quickly.

Pat inspects a centre pivot on corn and cotton grower Nathan Bradley's property.

  • [Pat Daley from Daley Water Services]

    Some prevention things if you ever know you are getting another flood coming through, which saves a lot of work afterwards, is the centre boxes can be undone... and the easiest thing to do instead of getting an electrician out is just to undo the cable ties and get a rope and winch that centre box up to a height you think it will be safe.

    That is not going to stop the gear boxes from getting submerged but this is the major bit of electrical equipment.

    In terms of how much water can go up the machine before they start to move... that varies between machines because some machines are heavier than others. But if these are just air only in the tyres it will get to a point where it does take some of the weight, and with a velocity of flow there it could shift.

    If you knew that you were in one of those situations, and it was going to happen fairly regularly, you could make tie down points for the base beams where you just use a turnbuckle and you tighten that down onto that tie down post and that would be where you could park the machine up generally.