Better irrigation

Jan 1, 2017- The agriculture sector remains the backbone of Nepali economy contributing above 30 percent to Gross Domestic Product (GDP), and employing a big portion of population directly or indirectly. While irrigation plays a vital role for better yields, we have not been able to use Nepal’s natural slopes and water flowing in the perennial rivers effectively. However, a recently introduced water lifting pump inspired by Nepali landscape is poised to change this.

Barsha pump, rolled out by a private company aQysta, has been conceptualised by Pratap Thapa who designed the pump in consideration of his farm on the slopes near a river in Nepal. ‘Barsha’ means rain in Nepali and the pump was manufactured to irrigate the lands near rivers and flowing water sources. The pump is expected to add to the irrigation options like treadle pumps, sprinkler and drip systems used to cultivate high value crops like vegetables and fruits. Currently, the pump has been introduced to and benefitting farmers in Nepal, Indonesia, Spain, Turkey and Zambia.

Zero emission

The pump can lift water to a height of 82 feet at a maximum rate of 1 litre per second. Interestingly, it does not require electricity or fuel for operation. It simply uses the river’s kinetic energy to lift water to a higher altitude. It can irrigate one to four hectares of land depending upon crop variety, soil type, irrigation season and facilities.

The pump beats the diesel- and solar-powered pumps in terms of sustainability and maintenance cost. This zero emission pump has very low maintenance cost and performs optimally in a river or a canal flowing at a flow rate greater than 0.3 cubic metres per second or a flow speed greater than 1 metre per second. The pump cannot cater to huge farms but lifts enough water to irrigate small paddy fields and vegetable farms.

Ancient Egyptian design

Hailed by farmers across the countries of implementation, the technology is not totally new. The pump has been inspired by a similar technology adopted by Morton Reimer to pump water from the Nile River in South Sudan during the 1980s. The stream-driven coil pump was based on a principle developed in 1746 AD. All these pumps have been inspired by the ancient Egyptian irrigation technique.

The pump, also known as a spiral or coil pump, has a water wheel with flexible hosepipe spiralling on it. The wheel is affixed to a platform that floats on the flowing river water.

As water enters through one end of the hosepipe, air gets compressed by the rotating wheel. This imparts kinetic energy to the water, enabling it to force out of the other end and reach a distance of about two kilometres. The water supplying end can be connected to reservoirs, sprinkler heads or drip irrigation systems.

The pump was introduced and experimented in 2014 by Practical Action and currently, a total of 25 pumps are in operation in 17 districts of Nepal. The pump, imported from the Netherlands, costs around Rs200,000. If assembled in Nepal itself, it will cost less than Rs100,000.

While solar water pumps also offer clean and cost-effective irrigation to farmers, Barsha pump is cheaper and easier to maintain by comparison. It saves 70 percent of irrigation cost throughout its lifetime. It also has an edge over a similar ‘Mangal pump’  that uses the kinetic energy of flowing water but needs to be connected to a gear box and centrifugal pump. Another water pumping device, the Rife River Pump, also operates without electricity or fuel and uses the energy from flowing water. However, it is more suitable for household needs.

The technology of Barsha pump can be scaled to serve different user requirements. The implementers are involving local manufacturers, importers and distributors to get the pumps manufactured locally and distribute them throughout Nepal.

Irrigation situation in Nepal

Only about one-third of the agricultural land in Nepal is irrigated because most farmers do not have easy access to irrigation facilities. Nepal, facing a chronic lack of fuel and electricity, will benefit from the pumps since there are more than 6,000 rivers flowing throughout the year around the country.

Since the pump does not need fossil fuel or electricity to operate and does not emit greenhouse gases, it will also be better for the environment if it replaces the expensive diesel pumps that are now used throughout the country to irrigate fields. It can prove to be an important cog in the wheel to provide year-round irrigation services to irrigable lands by effective utilisation of the water resources as mentioned in the irrigation policy.

Chaudhary is Communications Coordinator and Sinkemana is Senior Project Officer for Agriculture, Markets and Food Security Programme at Practical Action

Published: 01-01-2017 08:30

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