#1 Conserve water and ensure water quality
Irrigation water needs to be applied to the root zone of plants at a rate that can be absorbed into the soil, at the right time, and in the correct amount needed for plant health. This requires an efficient irrigation system, a good irrigation schedule, and the appropriate placement of plants.
Efficient Irrigation & Scheduling
Inefficient irrigation and incorrect scheduling account for the largest water waste in and around our homes. It is estimated that one half of the water applied to our gardens is wasted; that is, not used by the plants for healthy growth. This wasted water also affects water quality by allowing fertilizers and pesticides to run off our property into the gutters or leach into the ground water aquifer, our primary drinking water source. Overwatering can also cause plant health problems, as saturated soil prevents oxygen from reaching plant roots. There are many steps you can take toward creating a more efficient irrigation system and developing a better irrigation schedule.
To develop a more efficient irrigation system:
- Turn on the system monthly and observe its operation in order to detect water waste problems.
- Repair improperly operating equipment, including broken or leaking equipment, misdirected sprinklers, and clogged nozzles.
- Remove obstructions to the water distribution of the sprinklers by installing a taller riser, pruning a shrub, moving a plant pot or transplanting a plant to a different location. Sprinkler obstructions usually result in uneven or inadequate coverage, dry areas, saturated areas, and runoff.
- Ideally, all sprinklers on any one station (valve) should have all the same brand and model of nozzles, so that they are applying water at the same precipitation rate.
- Nozzles should be sized correctly to cover the area intended. Nozzles distribute water in different patterns (whole circle, ½ circle, ¼ circle, rectangle, etc.) and throw water different distances (most cover 8 to 15 feet).
- All emitting devices on any one station (valve) should operate at the same pressure. Most sprinklers operate at 30 to 35 pounds per square inch (psi) and apply water in gallons per minute, while most drip irrigation systems operate at 20 to 25 psi and apply water in gallons per hour; they should not be mixed on the same station. Standard sprinklers and drip emitters require different irrigation scheduling to account for the difference in pressure and run-time.
- To help with runoff, reduce the water application rate by using low precipitation nozzles (nozzles range from 0.43 to 2.25 inches per hour). Low precipitation nozzles apply water at a rate more similar to rainfall and result in better absorption and less runoff. These low precipitation nozzles will need to be programed for a longer run-time, but more water will be available to plant roots while experiencing overall water savings. Specialized irrigation equipment such as Toro Precision and Hunter MP Rotator low-flow nozzles are available at irrigationcontractor supply stores.
- Convert shrub, perennial, and vegetable beds to well-designed drip irrigation systems. Drip irrigation applies water only to the root area of plants which reduces overall water use and reduces weed growth between plants.
More Information on appropriate irrigation and design:
To develop a good irrigation schedule:
Consider the water needs of your plants, the application rate of water, the slope of your yard, how quickly the soil absorbs water, and the sunny and shady areas of the garden. All of these factors affect how frequently and how long any one irrigation station (valve) needs to run.
- Allow the top 1-2 inches of the soil to dry between irrigations to allow air to reenter the soil so that oxygen is available to plant roots.
- Observe how long it takes for water to accumulate on the surface of the soil before it starts to run off; this is the ‘runoff point of time.’
- Use an irrigation controller (sprinkler timer) with multiple start times to allow cycling. Cycling is two or more short run times that do not exceed the ‘runoff point of time’. Space cycles one to two hours apart to allow water to percolate into the soil. An 18 minute application of water onto a lawn might be divided into three 6 minute cycles.
- Use guidelines developed for both warm (e.g. Bermuda) and cool (eg. Fescue) season lawns that give approximate weekly water needs during various months of the year.
- Know your watering regulations and set the controller accordingly. City of Fresno City of Clovis
- Adjust the irrigation schedule as the weather changes to allow for plant needs during various seasons of the year.
- Turn off the irrigation controller during rain events and during the winter when irrigation is not needed.
- Upgrade the controller to have more features, allowing for better scheduling, such as more start times, a rain sensor, or a fully automated Smart Controller.
More information on irrigation scheduling
Lawn Watering Quick Tip (pdf) University of California, Agriculture and Natural Resources
UC Guide to Healthy Lawns University of California, Agriculture and Natural Resources
Lawn Watering Guide for California University of California Agricultural and Natural Resources (pdf)
Irrigation Scheduling Tutorial from Wateright, CSU Fresno, Center for Irrigation Technology
Irrigating Your Garden (pdf) City of Fresno guide
Placement of Plants
Plants have different water, soil, and sun/shade needs. Recognizing and allowing for these differences will enable us to develop a healthier garden and use less water.
Because of these differences, we should be irrigating one type of plant differently than we irrigate another type of plant so that each has optimum growing conditions. In addition, eliminating high water use plants will also save water.
- Group plants with similar water, soil, and sun/shade needs in the same area of the garden. Each of these areas is called a hydrozone. Irrigate each hydrozone with a separate station (valve).
- Plants are classified into water-use categories. Learn about thewater needs of the plants in your garden. When selecting new plants and trees, look for drought tolerant, native, or low-water use choices.
- Plants in a predominately shady area should be on a separate irrigation station (valve) from those in full sun to allow for different evaporation and transpiration rates. If you are using drip irrigation, you could also consider using drip emitters with a slower precipitation rate for shady areas (i.e. ½ GPM) compared to plants in sunny dry areas (i.e. 1 GPM).
- Lawn grasses, because of their short roots, need more frequent irrigation to replenish their shallow root zones, while trees and shrubs have deeper longer roots and require deeper less frequent irrigation. Irrigate lawn areas on a separate station (valve) from trees and shrubs.
- Lawn is the highest water use plant in our gardens, with cool season grasses (e.g. Fescue, Rye) requiring up to 50% more water than warm season grasses (eg. Bermuda, Buffalo, St Augustine). Minimize or eliminate lawn for large water savings in your garden.
- Warm-season grass is not over-seeded in fall. Newly seeded grass requires additional irrigation to germinate and maintain through the winter. If warm season grasses are not over-seeded, they are healthier since they are not over irrigated. In addition, warm season grasses will come out of dormancy earlier in the spring, because they are not shaded by winter grass.
More information on plant selection and placement of plants:
Creating a Fresno-Friendly Garden, Plant Choices and Water Conservation Tips for our Climate (pdf)
Drought Tolerant Plants City of Clovis Approved Plant List
Creating a Water-WiseLandscape Seven StepsTo Follow for our climate (pdf) City of Fresno brochure
A California-Friendly Guide to Native and Drought Tolerant Gardens Las Virgenes Municipal Water District
California Friendly Gardening Guide, Resources, Plant lists, and design templates by bewaterwise.com, Metropolitan Water District of Southern California and the Family of Southern California Water Agencies
Sunset Plant Finder (be sure to look up your Sunset Climate Zone
Water Conservation for Businesses
UC Guide to Healthy Lawns University of California, Agricultural and Natural Resources
Controlling Bermudagrass University of California, Agricultural and Natural Resources
Rainwater Harvesting and Ensuring Water Quality
All that is needed for a rainwater harvesting system is rain, and a place to store or direct it. The system can be simple or complex with most home systems being relatively simple to install and use.
The type of rain harvesting method used is dependent on local weather patterns and the volume of water that can be collected. Methods of storing collected rain water include storing rainwater in manmade vessels to be used for irrigation at a later time (e.g. rain barrel, cistern, or pillow) or directing rainwater onto the soil to allow it to filter slowly into the ground (e.g. rain garden or infiltration basin).
Within the Fresno/Clovis metropolitan area, the rainy season provides approximately 10 inches of rain a year, normally during a 3 to 4 month period, with the rain coming during our cool, primarily dormant season, when we generally do not need to irrigate. Collecting and storing rainwater in manmade vessels several months before it is needed may not be practical. However, if the garden has an area that does not receive water during a rain storm, such as an area under a roof overhang or plant pots on a covered patio, then collecting water in a rain barrel may be practical. Water could be used for irrigation shortly after it is collected, allowing space in the barrel to store additional water during the next rain event.
- The easiest rainwater to collect is from the roof via the roof gutter and downspout.
- Calculate the square footage of the roof surface and determine the total collected water possible during a normal rainfall event, allow for a collection device that can handle that volume of water.
- Rain barrels come in various sizes and are designed with a spigot to allow for water usage as well as a method to handle overflow; divert any overflow water away from structures. You can purchase one or make your own.
- Rain Gardens or Infiltration Basins should be directed at least 10’ away from structures by either the slope of the soil or through a drain line to an area that can hold standing water until it has had time to soak in. This area can either be handled as a graveled stream bed or an area planted with appropriate plants that can take standing winter water.
- Minimize solid hard surfaces in your landscape by using permeable paving for patios and pathways. Rain water percolates into the soil between the pavers, reducing runoff.
Capture the water that falls on driveway surfaces. Rainwater can be directed to a grassy swale or you may choose to install permeable paving designed for driveways.
More information on rainwater harvesting: Rain Wise, Managing Storm Water at Home Seattle Public Utilities
How to build a rain garden, Rain Garden Network
Rain Wise, Managing Storm Water at Home Seattle Public Utilities