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Landscaping for the Future – A Watershed Approach

July 2022. Climate models forecast more severe droughts in the future, but the future has arrived, and we must start adapting now. Landscaping appropriately for our climate is abench, Heuchera, Mimulus, and Penstemon - Jeff Silva - edited crucial part of that adaptation since more than half of our local water use is for irrigation. Now is a great time to learn about landscaping alternatives and start planning for your future home oasis. However, planting should be deferred until the drought has eased and additional water is available to help establish new plants.

Here we share ideas on how yards can be transformed into beautiful multi-benefit retreats optimized to withstand future droughts and be a sustainable solution. And we include suggestions on including grass as part of the new landscape.

Before we dive into the watershed approach, here is a quick summary of the irrigation requirements that will influence landscaping options.

  1. Spray sprinklers are prohibited after July 31, 2022.
  2. Low-volume/Low-flow (drip) irrigation systems are required (some exceptions for steep slopes and recreational public turf).
  3. Turf/Lawn watering is prohibited on commercial properties, including Homeowner Associations (HOAs), unless it is active recreation (state law) and has been issued a waiver from the HOA's water purveyor.
  4. Irrigation is limited to one assigned day per week (Saturday or Sunday)
  5. Running water features (fountains, decorative ponds) are prohibited unless there is existing valuable aquatic life.

Irrigation restrictions change with the level of water shortage, so they may ease up in the future. However, drought is an ongoing threat, and it makes sense to adapt now. Even before this current drought declaration, because of general concerns over water resources throughout the state, the state will be issuing water budgets to every water agency that will limit the amount of water each agency can use. Water budgets will be based on population but become more restrictive over time. So now is the ideal time to rethink ornamental landscaping and traditional irrigation systems and prepare for the future by adopting a watershed approach to landscaping.

What is the Watershed Approach?

The California Native Plant Society describes the three critical ingredients in a watershed approach.

  1. Keeping rainwater onsite by slowing runoff and allowing it to percolate into the soil. This can be done with a combination of landscape modifications like swales, contours, basins, and rainwater capture devices like rainbarrels or cisterns.
  2. Building healthy, living soil that can hold water and promote healthier plants. A one percent increase in soil organic matter can capture up to 16,000 gallons per acre. This translates to about a third of a gallon per square foot or 367 gallons in a 1,000 SF yard.
  3. Planting climate-appropriate plants. Drought-tolerant or California native plants? The chart below shows the water requirements of each. Not only do California native plants have significantly lower irrigation requirements than other drought-tolerant plants, but they have evolved to mirror California's rain patterns. This means they need little irrigation throughout the year, even in summer, when other drought-tolerant plants require much more. Once established, native plants require little to no water. It is critical to plant natives local to this region, not just to California (a big state!). Coastal Redwoods, for example, are adapted to the cool Northern California coasts and would be a poor choice here. Visit local nurseries (see Resources at the bottom) specializing in native plants for the best selection and advice. 

Plant water needs graph

Besides their lower water footprint, California native plants need less maintenance, no pesticides or fertilizers, and provide habitat and food for native pollinators (birds, bees, and butterflies). If you want to see and hear birds in your garden, there is no better way.

Drip (or MicroIrrigation) and Subsurface Irrigation

These systems deliver water directly to the root zones of plants. They are low-flow and low-pressure systems that slowly provide water directly to the soil allowing for better penetration, virtually eliminating evaporation and wind losses (can be more than 50% in spray systems), and reducing runoff. The USEPA has microirrigation guides for irrigation professionals and homeowners describing these systems' benefits, design, and installation requirements. Visit www.toakswater.org for Thousand Oaks requirements and additional resources.

Subsurface irrigation systems are low-pressure, high-efficiency systems that use buried tubes or drip tape to deliver water. These technologies were developed for agriculture in semi-arid, hot, or windy areas with limited water availability – a perfect description of Thousand Oaks' conditions. Since the water is delivered below the surface, soil crusting, runoff, wind, and surface evaporation are eliminated.

Turf/lawn options

While most lawn grasses require a lot of water and are thus highly discouraged, combining subsurface irrigation with high-quality soil and native- or drought-tolerant grass can provide an area for the kids or dogs to play that can withstand many irrigation restrictions. See options for native and drought tolerant grasses at these links.

Zones

Zones should segregate plants based on their water needs. This allows for high water use plants to be watered on a different schedule than low water need plants. However, many homeowners have historically divided their yards into zones based on layout, resulting in trees and shrubs utilizing the same irrigation schedule as surrounding turf.

Take this opportunity to layout future zones segregated by plant watering needs allowing for drought restrictions. During a severe drought, grasses and annuals are sacrificed to provide sufficient water for keeping trees and shrubs alive. Therefore, placing grasses and annuals in different zones from trees and shrubs makes it easy to shut off their irrigation during a drought while still watering your trees. California natives only need irrigation once to twice a month, whereas trees need periodic deep watering to establish deep roots, which help them to survive droughts.

Resources

California Native Plant Nurseries (check hours and days of operation)

Recent Los Angeles Times articles (some articles may require a subscription)

For more information, FAQs, resources, and specific water conservation requirements, visit our dedicated water website at www.toakswater.org. Rebates for turf removal (up to $3 per square foot) and other water efficiency measures are available at www.bewaterwise.com.

 

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