Microflood is a practical irrigation upgrade that turns traditional flood irrigation into a far more efficient system. It was recognised internationally with an SPE Environmental Stewardship Award, presented to Colin Austin at the SPE Environmental Conference in Detroit in February 2002. Originally developed to help deliver low-cost sustenance irrigation during drought in Ethiopia, Microflood also has global relevance because flood irrigation is the world’s largest water user.
Introduction — Microflood and International Recognition
Microflood, a process that transforms flood irrigation into a highly efficient irrigation system, received international recognition with the prestigious
SPE Environmental Stewardship Award.
The award was to be presented to Colin Austin at the forthcoming SPE Environmental Conference in Detroit in February 2002.
While the award is important, the bigger message is simple: there are practical ways to use the same water far better, and to do it without creating new environmental problems.
Why Microflood Was Developed
The technology was initially developed to provide a cheap and effective method of irrigation to grow sustenance food during periodic drought in Ethiopia.
This context matters because it shaped the design goal: it had to be low cost, robust, and usable in real conditions, not an expensive system that only works in theory.
Microflood also has wide application because flood irrigation is, by far, the largest user of irrigation water. If you can improve the efficiency of flood irrigation, the global impact can be significant.
Why Traditional Flood Irrigation Is Intrinsically Inefficient
Traditional flood irrigation often starts well. Water flows into the irrigation bay and begins to soak into the soil in the first section.
The problem begins as the flow continues forward. The next section is irrigated by water flowing over the first section, and the first section keeps soaking.
That means the top area receives water for longer and longer, and the infiltration depth increases beyond what plants can use.
By the time the water reaches the end of the paddock, the top of the bay has soaked deeply and can become saturated. Water is lost past the root zone, and this can also mobilise salt in the soil.
It’s Not Only Water Loss — Production Is Also Lost
The losses are not just about water quantity. Plants do not grow well when their roots are saturated.
In many flood systems the soil at the head of the bay becomes too wet while the rest of the paddock is still waiting for the flow front to arrive. This creates uneven growing conditions, reduced vigour, and lower production.
At the same time, water continues to soak down or evaporate away. The result is the worst of both worlds: wasted water and reduced yield.
Large Volumes, Big Channels, Wet–Dry Cycles
Traditional flood irrigation also tends to demand rapid application. To achieve that, growers often use large channels.
Large channels are a major source of waste due to seepage and evaporation. They also encourage the practice of applying large volumes at each irrigation — for example, around 50 mm per irrigation.
This creates a strong wet–dry cycle: soil becomes saturated, then dries, then is saturated again. This cycle is not productive compared to keeping soil consistently moist in the root zone.
The Concept Behind Microflood
The concept behind Microflood is very simple.
Instead of relying on one large flow of water moving over the soil surface, water is supplied from a pipe running down the irrigation bay with tap-off points along the length.
Where required, laterals (pipes with holes) may be used to spread the water across the bay. In the initial stage it works like regular flood irrigation, with water delivered from the first tap-off point.
How Microflood Changes the Flow Pattern
The key improvement happens when the flow front reaches the end of a section.
At that moment, instead of continuing to send water across the soil surface from the same entry point, the flow is diverted to the next tap-off point. This means water runs through the pipe rather than over the soil.
In effect, Microflood reduces the time any one area is exposed to flowing water, which reduces deep soaking at the head of the bay and improves uniformity across the paddock.
Small, Frequent Applications Instead of Big Floods
With Microflood, only small amounts of water are needed per irrigation — for example, around 5 mm.
Because application volumes are small, the soil is not saturated. That means:
- There is no significant loss of water past the root zone.
- The soil can be maintained moist rather than cycling between extremes.
- Plants remain in more stable conditions, which supports optimum production.
This is a fundamental shift: instead of forcing water through the system and accepting waste, Microflood uses controlled delivery to keep moisture where it is useful.
Why Small Flows Matter
Because the flows are small, water can be delivered economically through small pipes.
This avoids the seepage and evaporation losses associated with large open channels. It also makes the system easier to manage and scale, especially in locations where infrastructure costs are a barrier.
Production Gains and Environmental Benefits
Microflood is described as achieving up to 40% extra production from the same volume of water, without causing environmental damage.
The productivity gain comes from better moisture control in the root zone, less saturation stress, and improved uniformity across the irrigation bay.
A further benefit is the potential to manufacture pipes from recycled plastic bags, turning a source of litter into a valuable product.
Further Information
For more information email:
colinaustin@bigpond.com
