How Irrigation Works
Irrigation is one of humanity’s oldest and most important technologies. For more than 6,000 years, people have been moving water from rivers, lakes, aquifers, and rainfall to fields where crops would otherwise wither. Today, irrigation feeds roughly 40% of the world’s food supply on just 20% of its cropland.
All irrigation systems do one simple thing: they deliver the right amount of water to the root zone of plants at the right time. Too little water → drought stress. Too much water → root rot, nutrient leaching, and wasted energy. The art and science of irrigation is balancing these two extremes.
Where the Water Comes From
Surface water: rivers, lakes, reservoirs
Groundwater: pumped from aquifers through wells (the Ogallala Aquifer under the U.S. Great Plains is a famous example)
Treated wastewater: increasingly common in water-scarce regions (Israel reuses ~90% of its wastewater for irrigation)
Rainwater harvesting and runoff collection
The Science Behind It
Timers are powered by circuits to run the clock and control functions to automate your irrigation system. Sprinkler valves are used to divide the system. These divided sections are referred to as zones or stations and they run independently of one another according to the set program. The valve is connected to a zone in your irrigation timer automating the water duration.
Wiring connects the valves to the timer, valves are grouped together to create manifolds and manifolds are used to minimize wiring and make maintenance more convenient. The timer sends signals to each valve to increase or decrease the water flow accordingly.
When the timer reaches a start time, it sends a signal for the valve to open. Then, water flows through the pipes to that zone. In your case, for drip, it will have an emitter designated to go directly to the plant root. The water pressure activates the sprinkler head to pop up and begin watering. When the end of the run time is reached, the timer sends a signal to tell that valve to close. The water pressure inside the zone decreases and the sprinkler head disengages and moves on to the next watering zones if needed or shuts off when all zones have ran.
You can plug the timer right into an outlet in your garage or side of house based on your preference and use approx 1/2 KW or less per day and once everything has a regular watering schedule you won’t be using it daily so very efficient from time to water wasted from evaporation.
Think of it like setting a coffee pot timer to brew your morning coffee. Drip zones use an average of 8 gallons per minute per zone and sod zones 16 but way more efficient and effective than using a hose or sprinkler that connects to a hose.
How Water Actually Moves in Soil
Once water hits the soil, three forces take over:
Gravity → pulls water downward (drainage)
Capillarity → pulls water sideways and upward (how plants drink)
Evapotranspiration → plants “sweat” water into the atmosphere
Good irrigation managers keep soil moisture in the “Goldilocks zone”—neither saturated (0 kPa tension) nor too dry (below –50 to –80 kPa for most crops).
The Tech Revolution: Precision Irrigation
Today’s systems are getting scary-smart:
Soil moisture sensors
Weather stations + ET models (how much water the crop used today)
Satellite and drone imagery (NDVI maps showing stressed areas)
AI controllers that decide when and how much to irrigate with almost no human input
Example: A cotton farmer in Australia can now sit at home, open an app, and see that management zone 3 needs 12 mm tonight and the system turns on automatically.
The Future
Treated sewage and desalinated water will become normal sources
Solar powered pumps are already spreading across Africa
Genetic engineering for drought tolerant crops will reduce irrigation demand
“Deficit irrigation” (intentionally stressing wine grapes or almond trees) is improving quality while saving water
Bottom line: Irrigation isn’t just plumbing. It’s a delicate dance between water, soil, plants, weather, and human ingenuity. Done right, it turns deserts into breadbaskets. Done wrong, it can empty rivers and collapse civilizations. In 2025, with a global population pushing 8.5 billion and climate getting wilder, getting irrigation right has never been more important.
