Difference between revisions of "Rope and bucket"

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Rope and bucket system. Fass Toucouleur, Kaolack Region, Senegal. Photo: Fass Toucouleur Well Improvement Project.

This device is mainly used with hand-dug wells. A bucket on a rope is lowered into the water. When the bucket hits the water it dips and fills, and is pulled up with the rope. The rope may be held by hand, run through a pulley, or wound on a windlass. Sometimes, animal traction is used in combination with a pulley. Improved systems use a rope through a pulley, and two buckets – one on each end of the rope. For water less than 10 m deep, a windlass with a hose running from the bottom of the bucket to a spout at the side of the well can be used. However, the hygiene of this system is poorer, even if the well is protected.

Suitable conditions

Construction, operations and maintenance

Rope and bucket lifting device. Drawing: WHO.

Range of depth: 0–15 m (or more sometimes).

Yield: 0.25 litres/s at 10 m.

The simplest and cheapest method of lifting groundwater remains a rope and bucket in a wide, shallow well. This type of well can operate up to a depth of 100 metres, although they rarely exceed 45 metres. The rope and bucket lifter can be operated by humans or animals. Human operated rope and bucket lifters typically raise 10-15 litres/min from depths of 10-15 metres whereas an animal water lifter can raise 150 litres/ min from 15 metres. In the animal driven rope and bucket lifter, the rope attached to the bucket is passed over a pulley and fixed to the animal. The animal is driven down on an earthen ramp sloped at an angle of 5-10 degrees in order to lift the water.

A self-emptying container or mohte can be used in place of the bucket. The system consists of a leather container, shaped like a funnel. The container can typically hold between 100 to 150 litres. This arrangement can discharge about 130 litres/ min at depths of up to 9 metres.

The rope and bucket lifter can also be adapted to include two buckets which are raised and lowered alternately. In this case the pulling animal moves in a circular path and with the help of central rotating lever, rope and pulley arrangement the buckets move up and down. Each bucket has a carrying capacity of up to 70 litres. The buckets have a hinged flap at the bottom, which acts as a valve. Guide rods are provided in the well to control the movement of the buckets. The buckets are automatically filled and emptied during operation. This device can lift about 230 litres /min from depths of up to 5 metres.

Maintenance

The bucket is lowered and raised by playing out and pulling in the rope, or by rotating the windlass. Care must be taken to prevent the rope or bucket from be- coming soiled. Preventive maintenance consists of greasing the bearings of the windlass or pulley. Small repairs are limited to patching holes in the bucket and hose, reconnecting the hinge of the bucket, and fixing the windlass bearings or handle. All small repairs can be done by local people, and with tools and materials available in the community or area. Major repairs and replacements mainly consist of replacing the bucket, hose, rope, or part or all of the windlass. Woven nylon ropes may last for two years, but twined nylon or sisal ropes last only a few months. A good-quality hose may last for over two years, and most buckets last a year (depending on the material and quality). When people use their own rope and bucket, no extra organization is required. For community wells, a community committee usually organizes the maintenance and cleaning of the well, maintenance of the windlass, etc. Most repairs can be paid with ad hoc fund-raising.

Brikke and Bredero, in their publication Linking technology choice with operation and maintenance in the context of community water supply and sanitation: A reference document for planners and project staff, recommend the following O&M activities in the chart below:

Potential problems

— Poor-quality rope deteriorates quickly (e.g. sisal rope lasts for only a few months);
— The bucket falls into the well ... to prevent this, communities can keep a spare bucket and fit the bucket into a protective cage;
— The hose breaks frequently in windlass-and-hose systems;
— Poor hygiene, especially when the rope or bucket touches users’ hands or the ground;
— Communal wells tend to become more contaminated than family-owned wells, and the latter should be promoted whenever possible;
— The rope-and-bucket system is only suitable for limited depths.

Costs

From US$ 6 for a plastic bucket and 5 m of rope, to US$ 150 with a windlass, hose and closed superstructure, in Liberia (Milkov, 1987).

Field experiences

Area of use: All over the world.

Manuals, videos, and links

• 3. REVIEW OF PUMPS AND WATER LIFTNG TECHNIQUES. FAO.
• HUMAN & ANIMAL POWERED WATER-LIFTING DEVICES FOR IRRIGATION (full PDF). Practical Action.
• Extensive manual on water lifting methods: WASH technology information package. or (alternative link). UNICEF, 2010.

Acknowledgements

• Brikke, François, and Bredero, Maarten. Linking technology choice with operation and maintenance in the context of community water supply and sanitation: A reference document for planners and project staff or (alternative link). World Health Organization and IRC Water and Sanitation Centre. Geneva, Switzerland 2003.
• Human- & Animal-Powered Water Lifters for Irrigation. Practical Action.