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Irrigation-Conservation Corner-drought-Water Conservation

Spray Versus Drip Irrigation: Which is Best for You?

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Spray irrigation emits water in an overlapping pattern, while drip irrigation delivers water directly to the roots of plants. How do you decide which meets the needs of your landscaping?

The case for spray irrigation

Spray irrigation can be an efficient way to irrigate large landscapes with groundcover or uniform plant materials like lawns or meadows.

Spray systems apply water in gallons per minute (GPM), so if you know the application rate of each spray head, the distance between the heads, and the pressure of your system, it is relatively easy to figure out how much water is applied every time you run your irrigation.

Low volume spray heads apply water at about one-third the rate of conventional spray heads. Newer spray irrigation heads have improved spray with heavier droplets more resistant to wind. Landscaping with grade changes using spray heads should have check valves installed to prevent water flowing out of the lower point heads.

Challenges of spray irrigation include narrow areas surrounded by hardscape, or irregular patterns. Irregular patterns are particularly challenging, because spray irrigation requires head-to-head coverage to be efficient. Odd-shaped areas may be under or over watered. High-volume spray heads that emit water at a much higher rate than soil can absorb should be replaced.

The case for drip irrigation

Drip systems apply water in gallons per hour (GPH), so they often need to run for longer periods of time than spray systems. But the actual run time must always account for precipitation rate and runoff.

Installing subsurface systems (under at least two inches of mulch) is the most efficient way to irrigate nearly every type of garden area. Since the tubing is flexible, it can accommodate a variety of irregular shaped areas or rectangular areas when laid in a grid pattern, and in rings you can easily expand as trees or shrubs grow.

Challenges of drip irrigation include application of water too quickly for your soil to absorb. This needs to be considered when dripline grids are installed. Drip irrigation operates the most efficiently at low pressure (between 15 and 30 PSI). To achieve optimal performance, pressure regulation either at the valve or at the point of connection of the dripline to the buried lateral lines must be used. It is also essential to install some type of filtering system to keep the emitters from getting clogged.


This article was inspired by the 71-page Sustainable Landscapes Program guidebook available at SustainableLandscapesSD.org. The Water Authority and its partners also offer other great resources for landscaping upgrades, including free WaterSmart classes at WaterSmartSD.org.

 

Ensuring that spray heads are properly tuned and far enough away from buildings or impermeable surfaces helps maximize your water efficiency. Photo: California Department of Water Resources

Put Your Irrigation to the Test

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Turn on each valve of your irrigation system, and observe how quickly water begins to run off your landscaping. Note the time when each runoff occurs. For some systems, this could be immediately. For others it may take as long as five minutes.

Make sure that the spray irrigation is never running for longer than eight minutes at any one time.

Take notes on your irrigation plan, and turn off your irrigation until you are able to fix the follow issues:

• Do you have broken sprinkler heads?
• Are there heads that are blocked by plants or objects such as planters or lights?
• When the system turns off, does water come out of the lowest heads in the landscape?
• Are any heads in need of adjustment to they don’t directly spray onto the hardscape, such as sidewalks or patios?

Adjust your sprinklers to eliminate runoff

Several things can be done to minimize runoff due to irrigation. This is among the most important factors in using irrigation efficiently.

• Tune up spray irrigation systems so there is no overspray on hard surfaces
• Do not install spray irrigation in areas that are too narrow (generally eight feet wide or narrower)
• Move spray heads 24 inches away from buildings or impermeable surfaces
• Convert spray systems to micro or drip irrigation with the lower precipitation rates, pressure regulation and a filter
• In lawn areas, be sure to follow the organic maintenance practices to keep your soil ‘spongy’
• Replace standard overhead sprayers with high-efficiency rotator nozzles, or other types of low precipitation rate nozzles

Staying on top of your irrigation system can mean the difference between maximizing your water efficiency and unknowingly wasting water running down sidewalks unused into the storm drain.


This article was inspired by the 71-page Sustainable Landscapes Program guidebook available at SustainableLandscapesSD.org. The Water Authority and its partners also offer other great resources for landscaping upgrades, including free WaterSmart classes at WaterSmartSD.org.

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Watering your plants by hand is a great way to control exactly how much water they receive and observe them closely to be sure they are flourishing in the early stages.

Top Irrigation Tips for Smart Landscape Management

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Use these helpful tips to get the most from every drop of irrigation applied to your landscaping through the smart use of irrigation systems and supplemental hand watering.

Keep water on your landscaping

Watch your irrigation while the system is running. Check to make sure sprinkler heads aren’t spraying water onto sidewalks, patios or structures.

If water is being applied too fast for your soil to absorb it, runoff will occur. Puddling and pooling water may be an indication your water is being applied too fast or too often. Adjust your system to prevent this from happening.

Repairs to broken pipes and sprinkler heads should be made immediately, or your system should be turned off until those repairs can be made.

Cycle and soak programming eliminates runoff

Watch how quickly runoff occurs when you’re running your irrigation. This is the maximum run time for your irrigation controller in a particular hydrozone.

Divide the total minutes required in the hydrozone into blocks of time no longer than the observed runoff time. Allow a 30-minute rest period in between irrigation cycles.

Example: If you need 12 minutes of water in a certain hydrozone, but there is runoff after three minutes, you need to break down the 12 minutes into four separate three-minute long cycles, with 30 minutes between each cycle.

Best methods of hand watering

Hand watering is especially good when your garden is getting established. You can spend more time watching your plants to be sure they are flourishing in the early stages.

When your landscape plants are new, you may need to water more frequently because roots are shallower. Roots on a newly planted one gallon plant are only four to ten inches deep. This is why it’s a smart idea to plant during the rainy season.

Before hand watering, look at your plants. Do they appear droopy? Is the soil very dry? If so, give the plants a good drink. Don’t water more than two days in a row. Let soil dry out completely before watering again. Overwatering and underwater symptoms can be similar.

Once your plants are established after the first year, your sustainable garden will not need watering more than once or twice a month – if at all. Stop watering after the first seasonal rains begin and let nature take over.


This article was inspired by the 71-page Sustainable Landscapes Program guidebook available at SustainableLandscapesSD.org. The Water Authority and its partners also offer other great resources for landscaping upgrades, including free WaterSmart classes at WaterSmartSD.org.

San Marcos resident Jeff Moore's landscape makeover won recognition in the 2018 Landscape Makeover Contest. Photo: Water Authority

WaterSmart Landscape Contest Seeks Inspiring Entries

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The 2019 WaterSmart Landscape Contest invites homeowners across San Diego County to share their landscaping makeovers to inspire and encourage more people to consider their own makeovers by showcasing the beauty and variety of water-efficient landscapes.

The winning landscape from each of the participating water agencies will receive a prize valued at $250 and be recognized in print and online publications. The deadline to apply is April 26. Enter the contest here: www.landscapecontest.com

Customers of these local water agencies are eligible: the City of Escondido, Helix Water District, the City of Oceanside, Olivenhain Water District, Otay Water District, Padre Dam Municipal Water District, Rincon del Diablo Water District, City of San Diego, San Dieguito Water District, Sweetwater Authority, Vallecitos Water District, Vista Irrigation District and California American Water.

Jeff Moore stands in his San Marcos front yard featuring his award-winning waterwise landscaping work. Photo: Water Authority

Contest rules vary with each agency, but all entries will be judged on the same criteria. Judges are looking for overall attractiveness of the landscaping including its curb appeal and whether the plants are well maintained; a design with adequate plant coverage and permeable soil able to thrive with less water; efficient methods of irrigation; and climate-appropriate plant selection with minimal turf.

Water-efficient landscaping is beautiful

Raised planter beds and a living wall are features in this award-winning Olivenhain area landscaping project. Photo: Courtesy OMWD

San Diego County residents have embraced the new WaterSmart approach to their landscaping, installing water-efficient gardens and removing thirsty turf in increasing numbers.

One of those swapping turf for sustainable landscaping is San Marcos homeowner Rhonda Holmes. She won the 2018 Vallecitos Water District Landscape District contest. Holmes transformed the landscape at her home shortly after buying it. Her outdoor remodel included replacing the front and backyard turf areas with water-efficient plants.

She designed a garden that was smart on water while being beautiful at the same time.

“It’s really easy to do,” Holmes said. “I’d love to see more people try to do their part.”

The contest aims to inspire residents to consider a landscape makeover by showcasing the beauty and variety of water-efficient landscapes.

Video of 2018 Vallecitos Water District winners

Many previous winners have taken advantage of the San Diego County Water Authority’s free WaterSmart landscape makeover classes to help them successfully create and complete their projects. More than one million square feet of turf has been targeted for removal by course participants, generating a water savings potential of 36 million gallons annually.

Interested residents can learn about the next series of Landscaping Makeover classes and register on the WaterSmartSD website.

In addition to the benefits of reducing water consumption, water-efficient landscaping can improve a home’s curb-appeal and value, and reduce the need for costly, time-consuming maintenance. Many native plant selections also have fire-resistant qualities and provide habitat for local wildlife.

Outdoor watering accounts for roughly half of statewide urban use, and more in inland areas, according to a Public Policy Institute of California report. Savings can come from installing more efficient irrigation systems and replacing thirsty lawns with less thirsty plants.

Hydrozones-Conservation Corner-landscaping

Irrigation Efficiency Impacts Plant Health and Water Use

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Irrigation systems have a lot of interconnected mechanical elements. They must be thoughtfully designed, installed and programmed. Once in place, irrigation systems must be maintained properly for optimal performance.

“Irrigation efficiency” is a way of describing how well your irrigation system is delivering water for the beneficial use of the plants in your landscaping.

Issues that adversely affect the performance of your irrigation system can greatly reduce its efficiency and cause you to use more water than needed. The issues fall in three major categories: site conditions in your landscaping, irrigation control, and the uniform distribution of water by your irrigation system.

Three ways to maximize irrigation impact

There are three ways to improve your irrigation system efficiency by upgrading and continuously maintaining it for maximum efficiency.

• Smart Irrigation Management
• State of the Art System Upgrades
• Matching Irrigation to Your Hydrozones

Intelligent irrigation begins by understanding that “setting and forgetting” your irrigation controller is a thing of the past. Even if you don’t have a “smart” irrigation controller to adjust your program for weather conditions, you should be more proactive in managing your watering, and more closely try to match your watering schedule with the actual water needs of your landscaping.

Upgrading your system with state-of-the-art components is a good investment and the single most significant thing you can do to save water.

Tips on professional help with your irrigation needs

You may decide to get professional help with your irrigation system. Look for designers or contractors qualified to provide these services. Credentials such as the Irrigation Association’s Certified Irrigation Designer designation can help assure your project will be successful. You can also ask if your contractor is a Qualified Water Efficient Landscaper (OWEL).


This article was inspired by the 71-page Sustainable Landscapes Program guidebook available at SustainableLandscapesSD.org. The Water Authority and its partners also offer other great resources for landscaping upgrades, including free WaterSmart classes at WaterSmartSD.org.

Use a variety of contouring methods in your sustainable landscape design. Photo: Water Authority

Contouring Tips Help You Make The Grade  

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It’s smart to use existing depressions, slopes and contours for guidance when planning your landscape grading. If your yard is perfectly flat, you’ll need to move soil and features around to create more rain-holding contour areas.  

Do a Percolation Test, and prep your soil as needed to make it as much of a water-retaining sponge as possible before getting to work on rainwater capture plans.  

NOTE: If you are working with existing hillsides, it’s best to get professional advice before grading or other significant changes. Before any digging, call Dig Alert 8-1-1 or visit digalert.org  

Basins and swales 

Homeowners learn through the Water Authority's Landscape Transformation program that sustainable landscaping can be as lush as a lawn. Photo Water Authority turf

Basins and swales can take the form of dry creek beds, as in this award-winning water smart landscaping project. Photo Water Authority

Basins and swales are shallow depressions or channels no more than 24 inches deep on gently sloped or nearly flat landscapes. Basins and swales move water over short distances. The plants in and around the depressions capture and sink small volumes of surface water.   

Small, shallow depressions work best in clay soil areas, while sandy soils may accommodate deeper depressions up to two feet. Channels can be planted or lined with rocks and small boulders to resemble natural creek beds. 

Berms 

Berms are mounds of raised soil, usually planted, that can border basins and swales or be used alone. They help contain and move water around, increasing the holding capacity of basins and swales   

Boulders 

Boulders can add points of interest and slow down water runoff in your landscaping. Photo: Water Authority

Boulders can add points of interest and slow down water runoff in your landscaping. Photo: Water Authority

Boulders are useful to retain small berms or the edges of swales. They also create points of interest in your landscaping.   

This article was inspired by the 71-page Sustainable Landscapes Program guidebook available at SustainableLandscapesSD.org. The Water Authority and its partners also offer other great resources for landscaping upgrades, including free WaterSmart classes at WaterSmartSD.org.    

 

 

  

Using devices like this rain chain can help you slow and store rainfall for later use. Photo: Contraption/Flickr-Creative Commons License

Catch the Rain By Slowing and Storing It

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If rain gutters are installed on your house, water will be directed into downspouts, where it can move with great force and speed. This is especially true in a large storm. Instead of allowing downspouts to discharge directly on hard surfaces like a driveway, path, or patio, think about ways to redirect downspout water into vegetated landscape areas. 

One option is to replace downspouts with “rainchains” to slow down the water so it can be more easily absorbed when it reaches your landscape areas. Add a rain barrel or cistern at the bottom of downspouts or rainchains and let it overflow into the garden. 

If rain gutters are not installed, water shears off roof surfaces and can cause erosion damage. Areas under the eaves may be covered in permeable groundcovers such as pea gravel, mulch, or rocks to reduce the compacting force of water falling on bare soil. Spreading fresh leaf and wood chip mulch throughout the garden will slow down water. Healthy soil can withstand even the strongest rain.   

Ways of storing rainfall  

Rainwater can also be harvested and stored. Storage vessels include rain barrels and cisterns directly connected to downspouts  

Stored water can be released gradually into the landscaping between winter rainstorms, building up the soil sponge and ensuring that native plants get adequate water during the winter months when they need it most. If you need water in the summer and capture enough of it during the winter, you may be able to use your cistern water for irrigation  

Both rain barrels and above–ground cisterns can be relatively inexpensive to purchase and easy to install. Mosquitos are kept out using screens. With minimum maintenance and common sense, the water can be kept safe. If you plan to store rainwater, make sure the “first flush” is diverted directly into the landscaping before capturing the rainfall that follows.  

Properly placed trees also are excellent landscaping features to help capture rainfall, allowing it to be released slowly over time into the soil.  

 

This article was inspired by the 71-page Sustainable Landscapes Program guidebook available at SustainableLandscapesSD.org. The Water Authority and its partners also offer other great resources for landscaping upgrades, including free WaterSmart classes at WaterSmartSD.org. 

  

 

 

The first rain after a dry period is called the "first flush." It can wash pollutants off hard surfaces. A better alternative is to filter the first flush through your landscaping. Photo: Skyloader.Creative Commons

Capturing the First Flush of Rainwater

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The most important water to capture in your landscape is the first inch of rainfall after a dry spell. This is called the “first flush.”  

Rainfall in dry climates like the San Diego region is often a “first flush” repeatedly due to long stretches between rainy periods. 

The first rainfall washes away pollutants that have gathered on hard surfaces since the last rain. It needs to be filtered as much as possible by landscaping before it goes anywhere else, especially into storm drains that empty into the oceans. 

How much water comes off your roof? 

The shape of your roof doesn’t make any difference. The same amount of water falls on the roof whether sloped or flat. Measure a sloped roof either using an aerial view or from the ground without worrying about the slope itself. Just measure the outside edges the same way you would if it was flat, and calculate the square footage. 

Flat roofs covering a building in one contiguous shape are easier to measure. Some roofs are more complicated. Divide this type of roof into individual squares or triangles. Measure each one at a time, then add the figures together for your total roof area.  

Calculate your potential water capture  

Once you know the total roof area, you can determine the amount of rainfall it generates in gallons, then use the following formula to convert square feet to gallons.  

Formula: Rainfall in Inches x Total Square Feet x 0.62 = Gallons of Rainwater From the Roof 

Example using a 1,000 square foot roof: 1 inch of rain x 1000 x 0.62 = 620 gallons. 

San Diego’s rainfall total for “water year” 2018 was about 3.3 inches. Imagine this amount falling on a 1,000 square-foot roof. The total amount of water runoff during this water year would be 3.3 X 1000 X 0.62 = 2,046 gallons.  

Even in our dry climate, this rainfall adds up to a lot of water runoff. It’s easy to see how important it is to save as much of this water as possible in a landscape designed to be a sponge instead of a brick.  

 

This article was inspired by the 71-page Sustainable Landscapes Program guidebook available at SustainableLandscapesSD.org. The Water Authority and its partners also offer other great resources for landscaping upgrades, including free WaterSmart classes at WaterSmartSD.org. 

 

 

 

To properly capture water flow from rainfall, you need to assess where it naturally flows first. Photo: Tae Wook, Creative Commons License

Where Does Water Flow in Your Landscaping?

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To capture rainwater and any excess irrigation inthe soil or rain barrels, it is first necessary to understand what happens when water comes off the roof of buildings and moves across the property.  

Where is water moving? 

Make a copy of your landscaping site plan, and label it “Water Plan.” It should have the position of the buildings and major landscaping structures. During a rainstorm, watch what happens to water as it comes off the roof of the house and moves through the property. 

  • Are there any low spots where water pools? 
  • Does water run entirely off the property anywhere? 
  • Do any buildings or hard surfaces such as patios appear to be damaged by water? Is the damage caused by rain, by irrigation, or by both?

Note the direction water moves around the property from one area to another, or through multiple areas. 

Turn on irrigation systems for three minutes, and make a note about where there is any pooling or runoff.  

Assess the downspouts for water volume

Use the following process to figure out how much water comes off any hard surface, whether it is a roof, patio, driveway, or sidewalk. 

First, imagine the total roof area of your garage is 20 by 20 feet square, or 400 square feet, and water flows off it in two downspouts.  

If half the water goes into each downspout, the roof size for one downspout is half your total area. In this example, that is 200 square feet. 

Multiply the square footage for your downspout area by 0.62 to get the gallons of water per inch of rain coming from your downspout. Using our example of 200 square feet, the formula is 200 x 0.62 = 124 gallons.  

Once you have this number, you can plan for the resources needed to capture this water runoff for later use using tools such as rain barrels.  

 

This article was inspired by the 71-page Sustainable Landscapes Program guidebook available at SustainableLandscapesSD.org. The Water Authority and its partners also offer other great resources for landscaping upgrades, including free WaterSmart classes at WaterSmartSD.org. 

 

 

 

A simple, quick test will tel you how well your soil drains. Photo: Greywater.org landscape soil

Take a Soil Percolation Test

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In the San Diego region, rainfall can be unreliable and insufficient to sustain landscaping without careful planning and a little help. An alternate water source, such as irrigation, may be required.  

To make choices about the best, most efficient irrigation system for your landscape, it’s important to learn how well your soil drains.  

How does your drainage perform? 

Assessing how well water drains through your soil involves a simple percolation or drainage test. Follow these four steps: 

1) Dig a hole the size of a one-gallon plant, about 12 inches deep and 12 inches wide. 

2) Fill the hole with water and wait. Time how long it takes the hole to drain completely. This is needed to saturate the soil. 

3) Once the water has drained and none is visible in the hole, fill the hole with water again.  

4) Lay a stick or a shovel handle across the top of the hole, and measure the distance from the top of the hole at the handle or stick to the top of the water once every hour until it drains completely the second time. You may want to set a timer so you don’t forget to make your measurements. 

Percolation and soil quality 

If your soil drains more than four inches per hour: You have sandy soil. You need to add organic matter to improve the soil.

If your soil drains less than one inch per hour: Your soil needs extra help to drain. Try sheet mulching (link to page 19) 

If your soil drains from one to four inches per hour: Good news, your soil is a sponge and drains well. This is the goal.    

It isn’t difficult to build healthy, well-draining soil. Get our tips on how to create health soil here.

 

This article was inspired by the 71-page Sustainable Landscapes Program guidebook available at SustainableLandscapesSD.org. The Water Authority and its partners also offer other great resources for landscaping upgrades, including free WaterSmart classes at WaterSmartSD.org.