Outdoor Water Efficiency

Irrigation efficiency is very important. The average irrigation system is around 50% efficient, which means that half of a normal landscape area is getting overwatered to compensate for the less efficient areas. Though redesigning an irrigation system is generally the best option for efficiency, there are different ways to make a system more efficient without having to make such a large investment. Below is the procedure for a self outdoor water audit. Before an irrigation system can be adjusted for efficiency, it is important to identify the main problem areas. This step-by-step process will help focus your energy to improve the efficiency in your irrigation system.

The District also recommends using Certified Irrigation Professionals to perform this task as well.

Time to complete test: 15 minutes per zone. Following this simple procedure will be time well spent – your water bill will be lower and your plants will be happier.

Supplies: Six straight-sided, flat-bottomed containers (coffee mugs work well), cardboard strips, a simple calculator and a ruler

Procedure: Concentrate on turf areas first, as that is where the most water waste occurs. Turn on your first sprinkler zone. Note where the sprinkler heads are located, and look for the problems described in Table #1. Place the containers in various locations in each sprinkler zone – some in the middle and at the edges. Run your zone for exactly ten minutes. Use a piece of cardboard if necessary to dip into the water and then use a ruler to measure the discoloration on the cardboard. Mark these depths on a map showing the location of each container. If one or more of the containers has significantly less water than the others, then you have a dry spot. Refer to Table #1 and implement the relevant troubleshooting suggestions to get better distribution. Next, pour five of the containers into one and measure the depth again. This is the application rate of water in inches per hour for that zone. Complete this procedure for each irrigation zone.

For each irrigation zone, answer these questions:

How much water does the plant need?
This depends on the type of plant and local weather patterns. In this example, we will focus on turf in Vail in July, the thirstiest plant during the hottest month of the year. In Vail, turf should be irrigated about 1.5 inches per week in July. Let’s apply half that amount (0.75”) on each of two separate days each week. (Be sure to irrigate less in other months, and turn off the system if more than a quarter-inch of rain falls at one time.)

How much water is my irrigation system applying?
Let’s assume that in this example you poured all the containers together and measured exactly one inch.

How many minutes should each zone run?
In order to calculate run time for that zone, use the following simple formula to see how long it will take to water one inch:

 

 

Complete these calculations for each sprinkler zone and set your controller for the appropriate number of minutes. If your controller has the feature (and all newer ones will), set the ‘Water Budget’ feature to the following settings on the first of each month:

Month	% July (down valley)	% July (up valley)
April	31%	29%
May	56%	50%
June	81%	86%
July	100%	100%
August	94%	86%
September	50%	57%
October	25%	29%

 

Keep in mind that if you have clay soil and/or a sloping turf area that this runtime will need to be split into sections to allow water to penetrate and avoid runoff. In the above example, you would split the 45-minute runtime into three (3) sections of 16 minutes, allowing an hour between these irrigation periods for the water to soak in.

 

Table 1: Irrigation Efficiency Troublshooting

What to look for…	Caused by…	Problem results in…	How to fix it…
Tilted sprinkler heads	Usually mowers hitting heads or traffic	Poor water distribution and dry spots	Remove a little soil from around the head and make perpendicular to grade
Misting/High pressure	High pressure	Waste of up to 50% of water used in irrigation	Install pressure regulators on valves or replace sprinkler heads with new ones that regulate pressure*
Steady stream of water with large droplet size	Low pressure	Poor water distribution and dry spots	Change nozzles, reduce number of heads on a zone*
Low sprinkler heads	Installation errors or heavy mowers pushing them down	Poor distribution and dry spots due to deflection	Raise the heads by removing soil from around the sprinkler and gently pulling up. There is usually a swing joint that allows you to do this without breaking the line
Deflection	Tall plants in the way	Poor distribution and dry spots	Move the head or move the plant. Consider retrofitting with a drip system in shrub and perennials beds*
Mismatched sprinkler heads in the same zone	Poor design	Widely fluctuating precipitation rates cause wet and dry spots	Replace mismatched heads with appropriate types*
Irrigation during and after a significant rain event	Lack of rain sensor or intensive management	Water waste	Install a rain sensor to shut off your system during and after rainfall ($30).* Turn off the system during and after rainfall
Water is hitting adjacent hardscapes and running off	Sprinkler adjustment	Water waste	Adjust sprinklers so they stop before irrigating the hardscape; consider a landscape retrofit that pulls turf back from hardscape edges
Runoff	Sloped areas, clay soils	Water waste onto adjacent areas	Split sprinkler times to irrigate a fraction of the total time in two or three start times on the same day

*An irrigation professional is recommended for these improvements.

For more information, call Customer Service at 970-476-7480.

Below is a check list of items to make sure your automated irrigation system is operating at peak efficiency. Some items on the list may only need to be checked once per year, but others may require more attention. This list is also a great reference when discussing irrigation system maintenance with your contracted landscape or irrigation professional.

Main Seasonal Start-Up Checks

1. Thoroughly inspect the irrigation system after activation in the spring and make sure it is operating properly.
2. Check the water supply and pressure. Differences in the sprinkler system’s design, operating pressure, and actual water pressure can effect operation and efficiency.
3. Verify that the backflow prevention device is working correctly.
4. Inspect the valves to see if they operate without slamming open or closed in order to prevent damage from surges.
5. Look for debris (e.g., rocks, sand, or dirt) lodged in sprinkler heads and drip emitters.

 

Frequent Summer Checks

1. Check, adjust, and repair your irrigation equipment within 24 hours of mowing whenever possible.
2. Verify that heads are properly adjusted to avoid watering pavement or structures. Check the nozzle, arc, radius, level, and attitude with respect to slope.
3. Periodically verify that the plant material is healthy, has deep roots, and adequate soil moisture.
4. Reset automatic controllers according to the changing/seasonal needs of the plants as well as changing weather patterns throughout the summer. Irrigation systems should be rescheduled monthly to correct run times.

 

Continuous Summer Checks

1. Identify leaks and repair them promptly. Signs of leakage include particularly green spots, soggy areas around spray heads and above ground hoses, jammed spray heads, and torn hoses
2. Repair or replace broken hardware and pipes with materials that match the originals.Test all repairs.
3. Shut off irrigation systems and adjust whenever irrigation water falls or runs onto hard surfaces such as sidewalks, streets, or driveways.
4. Whenever possible, update and retrofit existing irrigation systems to take advantage of new, water-saving technology (e.g., rain shut-off devices, drip irrigation, ET sensors).
5. As plants mature, add or relocate system components as needed to maintain uniform distribution of water. Ensure that system modifications do not exceed the system watering capacity.
6. Understand the capabilities of the irrigation system and use them properly. For example, for spray irrigation systems, program the irrigation controller for multiple start times on watering days to reduce runoff and deep percolation below the root zone. That is, if the total watering time is 24 minutes, set the controller to three cycles of eight minutes each per cycle started each half-hour. (Drip systems should NOT be cycled in this manner.)
7. Whenever possible, incorporate the use of evapotranspiration (ET) data and modify it to your own plant and soil needs. Contact the Water Conservation Officer for local ET data 970.477.5426. Calculate the run-time of each zone to supply the needed water based upon the actual precipitation rate of the sprinkler zones, the water-holding properties of the soil, the changing weather conditions, and the plants’ water requirements.

Winterizing Irrigation System

1. Winterize sprinkler systems in our region by removing all the water from the irrigation system in order to prevent cracked pipes, broken heads, and other problems.

Other Helpful Information

• If you hire a maintenance contractor, ensure that he/she is experienced and reputable.
• If you have a very large property, consider a certified landscape-irrigation audit, which provides a thorough and comprehensive check of the efficiency of water application.
• Identify your priorities during water-limited situations, such as various stages of drought.
• The irrigation system is a management tool and cannot replace sound judgment.Source: Green Industries of Colorado’s Best Management Practices for the Conservation and Protection of Water Resources in Colorado

For more information regarding available conservation resources, contact Customer Service at 970-476-7480.

Please visit the links below for additional information on optimizing your outdoor water use.

• Irrigation efficiency tips (from Water Use it Wisely). Other topics found on this website include: planning and design, soil improvement, practical turf area, efficient irrigation, mulch, low water-use plants, and appropriate maintenance.
• How long should I run my irrigation system? How often? (from Colorado Yard Care).
• Fertilizing, aeration, mowing, and weed control (from Colorado State University Extension).
• Answers to frequently asked landscape questions [from Green Industries of Colorado (GreenCO)]. Click on the resources tab of the GreenCO website
  for “how-to” videos and more.
• Water conserving tips for HOAs and large commercial properties (from Green Industries of Colorado).
• Xeriscape (from Colorado WaterWise).