Water Containers for Low Cost Gravity-fed Drip Irrigation Systems
for Developing Countries
Drip irrigation is commonly used on high value horticultural crops in developed
countries worldwide where produce yields and quality are increased while at the same
time reducing water use by 50% or more. Simple, low cost drip systems have been
developed and used in recent years by poorer farmers in countries like India, Nepal, and
Bangladesh. Several of these systems are currently being tested on vegetable crops in
Myanmar.
One of the primary problems associated with these simplified drip systems is that,
without access to electric or other powered pumps, farmers in flat lowlands must elevate
a water container to obtain the required operating pressure. Common drip “kits” used in
India and Nepal use 10-55 gallon (38-208 liter) steel or plastic water containers such as
buckets and oil drums. While the larger drums work well, they add a significant expense
($7-20) to the cost of a simple drip system.
Gravity-fed drip systems for all but the smallest garden plots will usually require
raising the bottom of the container to a height of at least 3-4 ft (1-1.2 m) with 2 m
considered optimum. There are difficulties and expenses associated with the structures
required; filling containers at these heights is also difficult.
There is a desperate need to design inexpensive water containers which can easily
be raised to a height of 2 m and which are relatively easy to fill with a foot or hand pump.
One alternative which has been considered (but not fully developed) is a collapsible
water bag made from woven plastic (as used in rice bags) with a polyethylene plastic
liner.
The primary issues are: 1) making a relatively inexpensive container of sufficient
size (200 liter minimum) and 2) obtaining a suitable operating pressure of at least 3 psi*.
Some of the design considerations will be:
1. Manufactured in-country from relatively inexpensive materials.
2. Must accommodate a valve (tap) at/near the bottom without leaking
3. Ideally, users should be able to close the top to prevent evaporation and
reduce contamination (leaves, dirt, etc.)
4. Support structure/frame (or other means of elevating the water container)
should be inexpensively manufactured or easily constructed from locally
available materials (bamboo, etc.). Wood can be expensive in many areas.
5. It should be possible to clean the container periodically.
*1.5 psi is achieved from 1 m elevation or “head” (1 psi = 2.31 ft. elevation).