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By Tim Wilson, H2O Stewardship Solutions
A simple definition of this would be using some type of weather or soil moisture sensor to automatically adjust an irrigation system's watering schedule to more closely match actual plant water use. This is an emerging technology that is becoming widely accepted and promoted. It deserves some discussion since it has great promise, but its misuse could be harmful at worst, unproductive at the least.
This technology is a relatively new tool in our efforts to reduce landscape water use. Many different companies and approaches to this technology have cropped up in the last few years. Let's look at a few examples:
Sensor Based Technology (ET and soil moisture sensor based controllers)
This is an emerging technology. On the following pages is a brief description of this new control method aimed at reducing site water use.
Examining this technology a little closer, these devices fall into the following categories:
Historical ET controllers. These controllers have average ET rates preprogrammed into them (or you may enter in your own average ET numbers). Once they are set up they will water throughout the irrigation season based on these numbers. These are stand-alone and not very expensive.
Historical ET with specific local sensor input. These controllers are similar to the ones described previously, but they have an improvement. They run off of historical ET, but they have a local sensor (temperature, for example) that modifies the schedule based on local current conditions. These are stand-alone and the prices vary considerably on this type of controller.
ET control - local sensor input. These controllers operate directly off of current local weather based on some type of weather station, mini weather station, ET gauge, etc. The sensor is located at the sight, in the vicinity of the controller. In some cases, as in golf course, there might be a fully operational weather station at the sight. The difference between this controller and the Historical ET with specific local sensor input, is that this controller is governed by a sensor that is actually an assembly of many different types of weather sensors, not just one.
ET control - remote sensor input. In this application there is a controller at the site that communicates over radio, cell phone, pager, hardwire, etc., with a weather station network that can be as close as ½ mile from the site to as far as 100 miles away or more. Here the customer buys a controller and in some cases pays a nominal fee for a service to transmit the data to the on-site controller. There are varying degrees of human oversight in this process.
Soil moisture sensor control. Soil moisture sensors are installed in the soil at the site and are then wired back
If you have been in the green industry for a while you have seen many fads and "great ideas" come and go with mixed success. Maybe you have been considering using some type of SBT technology yourself. Perhaps you are unsure if it works and if it will be around five years from now.
One of the reasons that SBT has taken off in recent years is because many water conservation experts and water district/agency leaders have become discouraged with behavioral efforts to lower water use. For at least 25 years now most of the industry's efforts at water conservation have been geared towards educating the public and professionals on how to design, install, maintain, repair and schedule irrigation systems. In other words, our efforts have been focused on trying to change the behavior of the people who interact with irrigation systems.
Irrigation education and training has been a pillar of the industry's efforts and has produced some very well-trained and professional experts for the green industry. The issue isn't that education and training has not been beneficial to those persons who have chosen to participate in classes. The issue is this.has it resulted in sufficiently lowering water use in the landscape? Notice that the word "sufficiently" is used. There is no doubt that there has been some reduction of water use because of efforts to change user's behavior.
When looking at results from a more clinical perspective there are some shortcomings. Training and education, or behavior modification efforts have different levels. Below is an example of how a problem might be addressed using training as the solution:
Premise: A problem is identified and it is decided that training or a change in behavior is the solution to the problem. In this case the problem is wasting water in the landscape. Therefore, we send our employees to classes. During and after the classes students will pass through these next four levels. Some pass through all, others never make it to level one:
Level one - Students enjoy the class or training and they have a good time.
Level two - Students actually learn something and remember it.
Level three - Students change their behavior and begin using what they have learned in their job.
Level four - The change in behavior gives the results that initiated the reason for the training in the first place. In this case, the training results in lower water use.
Levels 1 and 2 are fairly easy to evaluate. Level 3 is a little harder since follow-up after the training in needed. Level 4 is very difficult to evaluate without quite a bit of research.
Many top water conservation experts feel that we never really reach level four in regard to water use reduction. To put it bluntly, many feel that attempts at trying to change behavior in regard to water use have not produced the results desired. We may have reached level three and there may have been some level four successes, but many feel that we have not effectively conserved water at the levels that will be required of us in coming years.
That takes us into the SBT controller thrust that we are seeing today. Water conservation experts are turning to technology to pick up where behavior has left off. The sentiment is that if green industry professionals won't effectively cut back on water use then maybe we should let technology take over the control and monitoring of irrigation water use. Many want to remove behavior from the water conservation equation.
There are additional benefits for water agencies that wish to spend money and resources on reducing water use through SBT controller use. Investing in SBT controller technology is clean, clear and measurable, compared to evaluating the results of training and behavior modification.
It is possible that the pendulum is swinging too far towards technology. Many organizations and agencies are placing too much emphasis on technology alone. There is a risk that they will not find the results that they seek and that this wonderful technology will suffer a bad reputation.
We might compare it to the introduction of drip irrigation to the landscape in the '80s. This new technology called drip was all the rage when it was first introduced in the landscape market. Just as we are seeing today with SBT controller technology, many people saw drip as a "hardware" solution to over watering. It soon became apparent that drip by itself would not magically save the world from all of its water problems. What we leaned was that this new thing called drip needed to be manufactured well, designed and installed by competent professionals and maintained on a regular basis. We learned this only after many disasters and failed systems. To this day there are still many green industry professionals who refuse to use drip because of those earlier failures.
Too many people pushed too hard and too fast to see the new technology implemented without the oversight of industry experts and proper training. The result was poor performance, bad press and industry reluctance to embrace it. Quite often water conservation experts are too quick to remove the human influence and try to bypass the experts with technology.
We must create an integrated approach towards this new technology. We must take the good from each, not replace one with the other.
Here are some ideas for a successful approach towards using SBT controller technology, while at the same time not relying solely on "Big Brother" to take care of the watering:
Use SBT Controller technology that uses "real-time" ET or soil moisture data, not just historical. Make sure the controller has some type of on-site sensor. It has been shown that using 30-year averages do not match up well to actual ET for the here and now.
No matter how wonderful the sales pitch may sound, don't assume that scheduling your irrigation can be handled on cruise control. You must pick a method that includes having knowledgeable and trained professionals involved in monitoring and tweaking the calculated schedule that the technology puts out.
A ten thousand dollar controller tied into Defense Department computers by optic fibers using artificial intelligence innovations will not help you if your system has problems. Things such as leaks, broken heads, stuck valves, poorly adjusted heads, incorrect nozzles, bad design, poor maintenance, etc., will still waste water. SBT Controller technology has not evolved to the point where nano-robots go out and fix your system when it breaks. Keep your system in good repair. Pay for good equipment, design and installation.
Crunch the numbers. Make sure your investment will pay for itself in lower water bills. In a perfect world everyone would do this because of a deep and profound love of the environment. In your case, however, most of your customers will want to see a return on investment.
Keep it simple. Time and time again we hear stories about customers investing in high-tech solutions only to see it abandoned 3 or 4 years down the road. If you're on-site employees can't or won't work with the technology, think twice about getting it. Do not delude yourself into thinking that you or your supervisors will have the time to work with it all the time.
Effective, short-term and long-term water reduction can result from placing good relevant technology in the hands of trained professionals. It is then monitored, checked and adjusted by humans. As much as we might like a "low flush toilet" for our landscape water problems we will have to arrange a marriage between behavior and technology.
SBT technology is a very good thing. It should be used when possible. Please remember, looking at the three ways to save water:
SBT technology only addresses water savings in one of the three areas: improving irrigation scheduling. Do not expect it to do more than it is designed to do.
Copyright 2003 by Tim Wilson, all rights reserved