Green Lawns and Low Water Bills

By Tim Wilson

Green Lawns and low water bills, yes, you really can have it both ways, and most of the time you can do it without major expenses.

First let me say that this article is written for the average landscape/irrigation contractor working hard for a living in the real world. This is not an academic, theoretical discussion of irrigation scheduling. If esoteric rhetoric is what you are looking for may I suggest you stop reading now?

Good, you are still here. Many of us struggle with trying to keep our customers landscapes green without over-watering during the hot dry summer months. There are several main reasons why this can be such a problem:

The climate in which we work demands high water use
The" watering window" or the amount of time that is allowed for us to water the site is limited
The irrigation system is in poor condition
We lack the time, resources or technology to change the watering schedules to match the weather
A combination of the these

Dealing with this wisely requires us to look at the irrigation problem from two different angles; we need to try to make good use of the water that we do put down (uniformity), and we need to pay attention to how long we are watering (scheduling).

The degree to which we take corrective action is dependent upon the customer's budget. If the customer has lots of money to burn through, and you work in an area that has no water shortage or distribution problems you may think that over-watering is not an issue, let's look at that for a minute before we move on.

Over watering can cause several problems beyond the obvious waste of water:

Fungus and disease in lawns
Low oxygen content in the soil and therefore stressed plants
Bad working conditions i.e. ruts from the movers, clogged mowing equipment from wet grass, etc.
Unsightly runoff
Damage to asphalt areas
Hazardous runoff into streets
Leaching or run-off of expensive chemicals beyond the root zone of the plant material
Environmental issues from chemical runoff and leaching

Having said all that, it is really in our own and our customer's best interest that we watch our water use, regardless of where we live and work.

Returning now to the before mentioned struggles that we face, let's look at some solutions.

At the heart of these problems lies the issue of uniformity, or how evenly does your system water? If you have to water 10,000 gals. just so that 5000 gals will be used beneficially by the plant, than your system is 50% uniform. If your plants only need 5000 gallons, than you have to waste 5000 because your system is in poor condition. What if you could water 7500 and the same 5000 was used beneficially by the plant? What about watering 6000 gallons and 5000 are used beneficially be the plant? Wouldn't that be better?

Here are some easy, low cost ways to improve your uniformity:

Raise low heads. Deflection of the plant leaves causes serious coverage problems
Adjust the heads so they water the correct area
Unplug or replace clogged, semi-clogged or worn nozzles
Put heads with check valves in the low spots
Re-do the nozzling so that it is MPR
Straighten crooked heads
Install psi regulating nozzles in high psi areas or where big psi variance occurs within a zone

Many of us think that in order to seriously improve a system's uniformity we have to make major, costly repairs. That is not the case! These things are simple and low cost, but the results are dramatic. It has been my experience that you could increase your uniformity by as much as 30% just by doing these simple adjustments.

Granted there are some problems that do need more serious and costly work, things such as:

Separating out zones so that shrub and lawn are separate or that spray and rotor zones are on different valves.
Installing psi regulating valves
Replacing heads
Re-designing the head layout

While sometimes the above major repairs have to be done to see a serious difference in uniformity, most of the time it is the easy simple things that will give you the biggest bang for your buck.

As you increase a system's uniformity you will find that you will need less time during the day to get the water down that the plants need to thrive. Remember the example earlier about the 10,000 gallons? Let's continue that for a moment.

Let's say you were watering for 2 hours to water 10,000 gallons just to get the plants 5000 gallons of useable water. If your system is now more uniform you might only have to water 6500 gallons to get 5000 to the plants. This is about a 25% increase in uniformity. What that means to you is a 25% decrease in watering time. That means that you could now get the same amount of usable water to the plants in 1.5 hours instead of 2. This can really help when part of your problem is a tight watering window.

Now let's look at the second issue of watering too long. Even if your system was 100% uniform (not possible on this planet!) you can still over water simply by letting the system water longer than is needed. This problem relates to the weather. In most areas of North America the weather is hotter and dryer in July and August than in October or April. The problem is that the customer rarely is willing to pay for you to come out weekly and adjust the schedule. In addition, what about those rare cool days that come up in July or those unseasonably hot days in October? There are several ways to deal with these problems:

Set the schedule up in the controller so that you can use the water percent adjust key for most of the schedule changes and only adjust the frequency a few times a year.
Set the controller up so that you only have to add or delete watering days instead of changing the duration.
If the system has central control then access ET data and change the schedules daily or several times a week.
Tie into weather stations for "Real time" ET updates.
Use an "ET" controller product or service or soil moisture sensors to schedule the system.
Install a rain switch.
Partner with a water management company to address scheduling issues.

There are many good classes and publications out there to help you better understand these issues. Associations like the IWMS, IA, ALCA, PGMS and PLCAA, or local groups such as CLCA can be a good resource.

Let's face it; we rarely get a phone call from a customer saying the lawn is just a little too lush and green! But let there be one dry spot and the phone rings off the hook.

Many of us are reluctant to reduce our water use for fear of an unsightly landscape. However, the items listed in this article can help you keep things green, more healthy, and with lower costs to your customer. Set your self apart by being viewed as a water management solutions company. Pay attention to the customer's water use and bottom line, they will appreciate it, and remember you when contract renewal time roles around!