01.05.12Kelly Duke

Innovations in Irrigation – A 40 Year Retrospective

40 Years of Irrigation Technology These irrigation innovations are all right up there with whiskers on kittens... Images courtesy of their respective equipment manufacturers

The start of a new year is a time for looking back at one’s achievements and looking ahead to a year full of promise and opportunities.  With that in mind I wanted to share my thoughts on the most significant irrigation innovations to emerge in the forty-some years that I have been employed in this profession.  The younger crowd may not appreciate some of these “innovations” since, from their perspective; they have always been the norm.  For those of us with four-plus decades in the industry, each became, or led to significant paradigm shifts in the way things were done.

These Are a Few of My Favorite Things…In Irrigation Innovations:

Starting at number ten and working toward ever more significant developments I present my top ten irrigation innovation milestones:

10.       U V Resistant Pipe

When we Californians maxed-out our conversion of prime agricultural land into housing we were forced to start carving up hillsides for new tracts.  Irrigating hillside landscaping is problematic in that it is both difficult and ill advised to trench for pipe installation on slopes lest you risk catastrophic erosion.  Installing conventional PVC on grade is no good since the pipe gets sun-burned and brittle;  also resulting in catastrophic erosion.  Before UV-resistant PVC pipe hillside systems used on-grade galvanized pipe which was expensive.  UV resistant pipe mitigated this and paved the way for the westward expansion of suburban blight.

9.         Drip Irrigation Systems

In spite of their ability to conserve water through precision application drip systems can require more technical expertise than our profession is generally willing to expend.  The only thing holding drip back from being number one in the charts is a serious commitment to the training of maintenance practitioners in how to maintain it.  More on this in a future post

8.         Code Purple

The requirement to identify non-potable irrigation systems with purple warning colors was first dealt with through various decals and tags.  The evolution of integrally purple colored pipe, valve bonnets, valve boxes, and sprinkler head and quick-coupler covers saved time and tedium in meeting the requirements for warning labeling.

7.         Central Computer Systems

Central controls using a PC linked to a network of field satellite controllers revolutionized irrigation for municipalities, business and academic campus settings, zoos, theme parks, golf courses and other large properties.  Central systems gave one the ability to update programming, be notified of problems, and monitor performance.  This irrigaiton innovation has saved labor, saved water, and paved the way for even greater advances in irrigation efficiency.

6.         Hand-Held Remote Controller Interface

The advent of the hand-held remote was of tremendous importance in testing, adjusting, and repairing irrigation systems.  No longer did you have to have two people on the job, or walk back-and-forth to the controller, or have to manually operate a valve (in a valve box set in the planter area five feet from sprinkler heads aimed straight at you.).

5.         Flow Sensors (As Tied to Master Valves)

Master valves have been around for a long time.  Their primary role had been to shut the main line off when the irrigation system was not running to prevent water loss in the event of an off-hours mainline break.  Tying the master valve to a flow sensor and integrating maximum flow thresholds for each irrigation zone expands the emergency shut-off capability to include broken laterals, missing heads, or stuck valves under the master valve’s control.

4.         Matched Precipitation Rate Nozzles

Advances in the engineering of both spray and rotor sprinkler nozzles has led to an expanded range of arcs and radii with matched rates of precipitation.  Irrigation Designers can reduce irrigation water waste through greatly improved coefficient of uniformity.

3.         Rotator Nozzles

As much as I like gear driven rotor heads, I love these small retrofit nozzles.  Watching them, I become as transfixed and meditative as a whirling Dervish.  Their low precipitation rate and low GPM demand allow them to be used in a wide range of applications from slopes to areas where the local static pressure has become reduced over time.

2.         Plastic-Bodied Pop-Up Sprinklers

In the beginning there were stationary brass spray heads.  This led to brass pop-ups but, due to the weight of the brass, pop-up height was limited to around two inches.  Modern plastic pop-up heads overcame the height limitations, added integral filter screens, retraction springs, integral check valves, and eventually pressure compensating / pressure regulating functions, and matched precipitation rate nozzles.  This irrigation innovation resulted in improved uniformity and accuracy of delivery, reduced misting, and the elimination of low-head draw down.

1.         “Smart” Controllers

Early irrigation controls were simple clockworks with pin or cam-actuated switches that turned valves on and off.  The advent of inexpensive microprocessors allowed for more sophisticated controllers and paved the way for the introduction of water budgeting functions, flow-sensor over-ride functions, and two-way communication. The result is the “Smart Controller” that relies on moisture sensors, imported ET data, or an on-site weather station’s input to automatically adjust frequency and duration of irrigation cycles on a zone-by-zone basis.  Smart controllers can make even the dumbest irrigation design more efficient.  These controllers have become so affordable that I am ashamed that I have not installed one myself.  So, my New Year’s Irrigation Resolution is to retrofit to a “Smart” controller myself and start walking the talk.


K. F. Duke

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Kelly Duke

Not many people can say that they have dedicated their life to the landscape industry. Kelly Duke can. His diverse background ranging from maintenance to estimating, to design, along with a passionate commitment to his trade has given Kelly a lifecycle perspective to landscaping. As the leader of the ValleyCrest’s Pre-Construction Services team, he analyzes early conceptual designs to determine whether or not and how they can be built within budget while meeting long-term design and maintenance goals. Many of the projects that come across Kelly’s desk require he examine the cost and savings of baseline water use in comparison to high efficiency alternatives.


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  1. Thursday, 10:39 Alan Harris

    #10 I knew the slopes were irrigated in part for fire control, but had always wondered why the pipes were left exposed. Makes perfect sense.

    #1 is one of the few ways to make me NOT hate irrigation

  2. Friday, 7:55 Randy Barron

    A great list, Kelly! I’d have to make it the 12 days of New Year’s and add in-line drip and rain sensors to the mix, tho :) In-line for its robustness (is that a word?) in high-traffic areas and applicability to sub-surface drip and linear plantings, and rain sensors for their low-cost fix to a perennial (no pun intended) problem and ease of installation…

  3. Monday, 8:12 Warren Gorowitz

    Great list Kelly! So what do you think will be the new #1 in the future? Or does that product even exist yet?

  4. Monday, 11:31 Kelly Duke

    I a looking for totally wireless technology between the clock, valves, and sensors. The utility companies are already on to this with wireless meter reading. The potential problems may be with spurrious electronic emissions turning your sprinklers on or off at inopportune times.

  5. Monday, 11:43 Kelly Duke

    I agree on both your suggestions but I ran out of numbers. Maybe I will co-opt your suggestion and do the “12 days of…” idea next year. Rain Sensors are a very simple and relatively low tech solution. The wireless variety are even more brilliant by allowing proper placement of the sensor. Undoubtedly the 100 winners of wireless rain sensors awarded through this blog can testify to that.

    Better yet, the compact weather stations capture a ton of relevant data and are helping to expand opportunities for ET driven Smart Controllers in areas not served by realtime ET data providers.

    As for in-line drip emitter tubing, I have both point and line emitters at my home and am slowing converting over to all emitter line as the more effective solution for my particular type of planting (Urban Wildlife Sanctuary). KFD

  6. Tuesday, 4:48 Chris Perry

    Kelly, “…the westward expansion of suburban blight.” Is that cynical or sarcastic or both? Whichever, it’s classic. Regards, C

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