By Luke Frank
Smart irrigation is the efficient development, conveyance and management of water. It always has been. This ideal has been redefined by humankind over many thousands of years; and logically so. Civilization has progressed from a dependence on geography and climate, conforming to watersheds and surface resources, to outright defying physical forces in delivering millions of acre feet of water to major megalopolises across the planet.
From an engineering standpoint, it’s been an amazing 10,000-year journey. Early irrigation techniques depended on the physical geography and geology of the area, and the skills available to divert water from natural sources through artificial channels or ponds where it was applied to crops.
Egyptian agriculture along the Nile was based on growing winter crops following annual floods. Egyptian irrigation came from a single source, the Nile, a river too powerful to control. Irrigation was passive in construction, and built relatively high along the riverbank to deal only with the peak of a flood. Such irrigation systems couldn’t carry water any great distance away from the river.
Ancient Egyptians built large flat-bottomed basins for growing crops along the riverbanks, and simple sluices that diverted water into them at a flood’s peak. Irrigation water flowed through several basins in succession, controlled by simple gates. Ditches and canals were short, and the typical irrigation delivery system was very local. Nevertheless, this was a pretty clever system of water delivery.
Mesopotamia, a low-precipitation region supplied by only two major rivers, the Tigris and the Euphrates, had its own thing going some 6,000 years ago. Because of the region’s geography, Mesopotamians had to worry about water storage and flood control, as well as irrigation. Although the Mesopotamia plain is relatively flat, the bed of the Euphrates is higher than that of the Tigris. Engineers used this gradient as soon as irrigation systems became large enough, using the Euphrates water as the supply, and the Tigris channel as a drain.
Mesopotamian engineers built very large weirs and diversion dams to create reservoirs and supply canals that carried water considerable distances across the flat countryside. The scale of their irrigation was larger than in Egypt, and Mesopotamian irrigation was intrusive and active . . . and smart.
When in Rome…
The early Romans devoted much of their time to public works projects. The prosperous early Roman citizen typically had a dozen-room house, with a square hole in the roof to let rain in and a cistern beneath the roof to store the water.
Many aqueducts were built by the Romans, who needed extensive aqueduct systems for their fountains, baths, and gardens. Roman aqueducts were built on elevated structures to provide the needed slope for water flow. Pipe making — using bronze, lead, wood, tile and concrete — was in its infancy, and the difficulty of making large, high-quality pipes was a hindrance. Most Roman piping was made of lead, and even the Romans recognized that water transported by lead pipes posed a health hazard.
A typical water-supply system for a Roman city was a spring or a dug well, usually with a bucket elevator to raise the water. If the well water was clear and of sufficient quantity, it was conveyed to the city by aqueduct. In addition, water from several sources was collected in a reservoir and then conveyed by aqueduct or pressure conduit to a distributing reservoir.
Three pipes conveyed the water — one to pools and fountains, the second to the public baths, and the third to private houses. Older aqueduct systems often involved vast networks of interlinking segments. In their day, these were sophisticated irrigation ideals.
Over the millennia and closer to home, extensive dam and canal systems were engineered to capture and deliver water to crops in Mexico, Arizona and New Mexico. Some of the spillways were improved, and floodgates were used in some spillways. The canals were modified somewhat during this time. Different cross-sectional areas were used, and some were lined with stone slabs. During this time, irrigation was more carefully controlled compared to the earlier methods of seasonal flooding.
The Modern Irrigation Era
Fast-forward to a time of real revolution in irrigation: in the United States, smart irrigation innovation rocketed into the 20th Century with more than 150 patents aimed at improving the grower’s ability to deliver water more effectively. Academia also picked up the pace, with new colleges of agriculture and mechanical arts. We moved from animals to implements in developing water systems in our fertile plains and valleys.
By 1900, in California’s Central Valley, concrete pipe feeders with vertical risers were fitted with various valves to control flow. Measuring flumes were developed to further improve the efficiency of irrigation water flow. As our agricultural enterprise accelerated through smart irrigation methods, technology began spilling into urban landscapes. Charles Skinner (who later helped form the Association of Sprinkler Irrigation Equipment Manufacturers, the Irrigation Association’s predecessor) introduced pressurized, overhead irrigation.
Hose-end sprinklers were developed by L.R. Nelson, who also introduced us to the turf head — a fixed, square-patterned sprinkler connected to a hose with a brass coupling. In the 1930s, Nelson developed an underground irrigation system, an incredibly smart form of irrigation. He wasn’t alone. Entrepreneur George Moody realized an untapped opportunity to develop sprinkler systems for commercial, municipal and residential applications and developed his business in Southern California. Moody was the first to blend hydraulic controllers and valves, creating the foundation for an automatic sprinkler system. Meanwhile, John Brooks, a master plumber, was installing irrigation systems for large estates in Michigan. Subterranean, pressurized, zoned irrigation — very smart.
Names like LaFetra (Rain Bird), Wade, Buckner and Reinke joined the ranks of Nelson, Moody and Brooks; pumping out new patents, materials, techniques, specialty equipment and product distribution. Other names, like Ed Hunter and King Ewing, would be added to the list. With the rush of complex, diverse new technologies in the couple of decades after the War, understanding which combination of irrigation components would best perform on a given site became a specialty. The independent irrigation consultant was born in 1972.
The pace of irrigation science since has been astounding, from computerization to fertigation. It’s nearly impossible to record all of the smart irrigation advances in the last 30 years.
As an independent organization, the Irrigation Association has developed a rigorous slate of standards and specifications to qualify irrigation products as “Smart.” It’s an opportunity to qualify irrigation product performance and raise water-use awareness. But the people who conceive, mold refine and forge new ideas make irrigation truly intelligent. As biology, chemistry, agronomy, horticulture, soils and engineering influence the precision of irrigation design, installation and management in the decades to come, Smart Irrigation will be redefined once again.
Luke Frank, communications director for the American Society of Irrigation Consultants (ASIC), is a writer, editor and publisher in the green industry focusing on water resource development, management and conservation. ASIC is an organization of professionals within the irrigation industry that provides a forum wherein irrigation design professionals can meet to exchange information and advance skills and techniques in irrigation design, installation and product application. For more information, visit www.asic.org