Consider the following factors:

  1. It is best to restrict the use of pumping, drainage or diversion to sites where the bottom ooze is so deep or the water so turbid that little aquatic vegetation is found during the growing season. Elsewhere, other methods should be considered which are likely to have a less drastic effect on aquatic life.
  2. Provide for the water to run off safely without damage to land or water of owner ’s downslope. Do not just pour it out over the land, unless you are sure the volume involved will not drown or smother vegetation, cause erosion, or pollute other water supplies. Where a road borders the site you can pump out into the road drains, provided you are pumping only unpolluted water, and not sludge. Make sure the drains don’t empty back into the site a few metres further on.
  3. Check man-made ponds for drains through which the water can be released. Other waterways may have natural cut-off points where water can be diverted into another channel. These may make pumping out unnecessary, or reduce the amount of water to be pumped.
  4. In some situations, such as a small pond on a higher level than an adjacent channel, it may be possible to siphon out the water instead of using a pump. Use plastic hose-pipe about 37mm (1.5”) in diameter. The outflow point must be lower than the intake.
    One method is to put the pipe over the bank so that its outlet is in position. Put an airtight plug in the outlet and fill the hose with water from the pond. When it is overflowing, put your hand tightly over the intake end and put it quickly under water. Take the plug out to start the siphon working.
  5. After draining or diverting as much water as possible by other means, the remaining volume will need to be pumped. Once the water has been drained or pumped out, cut channels and a sump in the bottom muck to allow further drainage. Do not cut into an artificial lining.
  6. Let the waterway dry out for an adequate time before beginning hand clearance of the bottom muck.

Choosing a pump

  1. Where the need is to remove water, the pump must get it out faster than it seeps in elsewhere. The rate of leakage through coffer dams or inlet sluices must be estimated before assuming that the pump can cope. Manufacturer’s claims of pumping ability should be taken as the maximum possible under ideal conditions.
  2. A pump which can keep a site dry once drained may be inadequate to pump it out in the first place. It may be worth hiring a bigger pump for the initial clearance, and use a smaller one to keep the site dry.
  3. Check the head capacity of the pump, that is the vertical height of which it is capable of pumping water. Ensure this meets the conditions on site. The pump will need sufficient length of inlet and outlet hose.
  4. Check whether the pump needs to cope with varying water levels, which may leave the inlet sometimes exposed to the air.
  5. Pumps increase in size and weight as the hose diameter increases. Pumps are supplied with a carrying handle, full cradle or wheeled dolly as appropriate. A 50mm (2”) pump is easily handled by two workers, and can be carried across boggy ground without trouble. An 80mm (3”) pump can be shifted by several people together, and is the size most often used on conservation projects.
  6. Pumps may be diesel or petrol-fuelled. The bigger pumps tend to be diesel-fuelled, and can run for around eight hours without being refuelled, allowing use overnight to keep an area free of seepage for example.
  7. Standard water pumps are designed to pump water only. Trash or sludge pumps can handle solids up to about 25mm (1”) diameter, and are suitable for pumping out dirty water and sludge. Do not use a pump for sea water, unless the pump has corrosion protection.
  8. For major sludge clearance, it may be worth hiring a larger machine. Most large farms and agricultural contractors have tractor-operated slurry tanks with pumps and spreaders, that can handle wet sludge. A ‘gulley cleaner ’ is a pump-lorry combination used by local authorities and waste disposal companies for clearing drains and septic tanks. Contact local plant hire contractors and agricultural contractors to find out what is available in your area.

For further details of pumps used for conservation management, see Burgess, Neil and Hirons, Graham JM (1990). Two leading manufacturers of pumps are Sykes and Honda, with hire, sales and service available throughout the UK.

Using  a pump

Note the following general guidelines for the use of portable pumps. Follow manufacturer ’s instructions for use and maintenance, or obtain instructions on use from the plant hire company.

  1. Pumps must always be sited on firm, level ground, which may require the placing of a temporary platform in muddy, soft or sloping conditions.
  2. Position the pump as close as possible to the water, since the shorter the inlet hose the better the vacuum.
  3. Check that the outlet hose has no kinks in it. Once the pump starts, keep an eye on the outlet hose to ensure that water flow is unrestricted.
  4. Check that the engine has sufficient fuel and oil of the appropriate type.
  5. Prime the pump as necessary, and drain the water in the pump after use.
  6. After use, wind up the outlet hose so that the pump connector ends up on the outside of the roll, for easy attachment next time of use.

Safety guidelines

  1. Due to danger of exhaust gases, do not use a pump in confined spaces. For operating, place the pump at least 1 metre from walls or buildings.
  2. Do not operate near vehicles or flammable objects.
  3. Do not replenish fuel during operation.
  4. Ensure the pump cannot tip over or drag during operation.

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