The Rest of the Story...."Stepping Up Irrigation”

By Kimberly Duncan
ECHO Asia Intern

Not to be left out of the wet, ECHO partner, UHDP, has commissioned not one, but two pumps from our Burmese visitors as they also prepare for drier days. A rope and washer pump being built for them retains the full body of the bicycle being used to provide rotation which is pedaled rather than cranked by hand like the ECHO pump; hence, we’ve begun referring to it simply as the “bicycle pump.” Other than the leg power being used to make the wheels go round, however, the concept is exactly the same as the ECHO Asia pump described in our previous posting.

The second pump is a treadle pump. This one is made almost entirely of metal, with the exception of the PVC pipe used to support the operator; however, hundreds have been built around the developing world using bamboo, wood, or other materials. This one was purchased in Tachilek, Myanmar and though not entirely identical to the “pulley and rope” arrangement typical of many treadle pump designs that can found on the Internet, it runs on the same concept. We’ve borrowed Climate Lab’s explanation of the mechanics:

The treadle pump consists of two parts, the pump and the operating mechanism. The pump is generally made of metal and has two cylinders that are connected to a suction pipe at the base and an outlet spout at the surface. The operating mechanism is made up of metal, bamboo, or wood foot pedals that are attached to a superstructure that the operator can hold onto for support. As the operator of the pump shifts their weight on the foot pedals, plungers inside the cylinders reciprocate the motion and draw water alternately into each barrel. Non-return valves protect the inlet and also allow the plunger to move down through the water in the cylinder on the downward stroke without forcing it back down the suction pipe. The upward movement of the plunger lifts the water in the cylinder out the spout and simultaneously draws more water into the barrel of the suction pipe. The water is either lifted onto the field directly, into a pond or into an irrigation canal. (Palumbo)*

Both pumps can lift water from standing water or wells. In both cases the distance from the water source or depth to the water table will affect the amount of water that can be brought up and at what rate. (Most treadle pumps can draw from a maximum 7 meters depth.) In the case of a treadle pump, the size of the piston cylinders and the draw length of the pistons themselves will also determine volume. Cylinders on the UHDP pump are 101mm in diameter; stroke length about 250mm. The bicycle pump sourcing water from the pond is currently functioning at 12 liters per minute. I’m told that the treadle pump, when completed, should be able to pump 30 liters per minute from the same pond.

As mentioned before, a lot of work with treadle pumps is being done around the developing world. Huge success has been found in areas like Southeast Asia (particularly in Bangladesh) where water tends to be more readily accessible; however, the pumps have also worked well in parts of semi-arid Africa. The Food and Agriculture Organization of the United Nations (FAO) has some extremely detailed and helpful publications describing them. For some fascinating bed-time reading, check out the following links:

FAO TREADLE PUMPS FOR IRRIGATION IN AFRICA
http://www.fao.org/docrep/005/x8293e/x8293e00.htm

FAO - HOW TREADLE PUMPS WORK (continuation of publication above
ftp://ftp.fao.org/docrep/fao/005/x8293e/X8293E01.pdf

FAO TECA BAMBOO TREADLE PUMP INDIA
http://teca.fao.org/technology/bamboo-treadle-pump-india

FAO TOTAL LAND CARE - TREADLE PUMP IRRIGATION
http://www.totallandcare.org/Projects/FAOTreadlePump/tabid/93/Default.aspx

FAO REPOSITORY SITE WITH MULTIPLE PUBLICATIONS
http://www.fao.org/documents/jsp/empty.jsp?cx=018170620143701104933%3Azn2zurhzcta&cof=FORID%3A11&q=TREADLE&x=0&y=0&search_radio=docRep

THE ASHDEN AWARDS FOR SUSTAINABLE ENERGY
http://www.totallandcare.org/Projects/FAOTreadlePump/tabid/93/Default.aspx

COOPER-HEWITT - DESIGN FOR THE OTHER 90%
http://other90.cooperhewitt.org/design/bamboo-treadle-pump

*Palumbo, Jamie. "Treadle Pumps." Climate Lab(beta). Creative Commons Attribution Share Alike, 31 March 2010. Web. 11 Aug 2011. http://climatelab.org/Treadle_Pumps.