Olivenhain Municipal Water District’s 2020 WaterSmart Landscape Contest winner Laura Lisauskas redid her family’s street-facing sloped side yard. Photo: Olivenhain Municipal Water District

Protect Your Hillsides and Slopes 

San Diego County features many native canyons, and many homes are located in proximity to a native canyon. Native canyon hillsides near your home should not be disturbed. The more you can adapt your home’s landscaping to Nature’s landscaping, the healthier and more low maintenance it will be.

Your home may have been built on canyon slopes leveled or filled. When planting in previously disturbed or built slopes and hillsides, choose low-water use plants and trees, especially deep-rooted native plant species. Climate-appropriate plants with strong root structures are the best choices. Their powerful root systems can help hold your soil together.

Coarse compost and mulch can be applied directly to hillside and slope surfaces, providing protection from the force of rainfall and shading exposed soils, if your slope is gentle with a 33% grade or less. With occasional and gentle irrigation, mulch will “knit” together.

Compost blankets are another type of erosion control mat applied to the soil surface to protect and preserve it. They can be used alone, with coir mats or other organic-engineered material with biodegradable grids for stabilization. Mats allow water to penetrate through to the underlying soils while retaining loose soil and debris, preventing erosion. You can plant right through them, or use pre-seeded products.

Irrigation tips to help preserve hillsides

Be sure your irrigation plan takes into account hills and slopes to prevent wasting water and erosion. Photo: Pixabay

Prepping Hillside for planting

When preparing a hillside for planting, plan your irrigation before doing any work. Low-volume rotating spray heads are ideal for sloped areas, if the space is large and the groundcover is uniform. Inline emitter drip tubing can also be effective, especially for wider-spaced shrubs and trees.

Water can be applied in repeated short periods over the course of 24 hours so it can be fully absorbed between application times. Runoff, erosion, and efficient deep watering should be factored into all landscaping plans, but especially for hillsides.

NOTE: When using a drip irrigation system, emitters should be placed above the plant basin. Spray systems should have check valves in all lower heads to avoid low point runoff. Irrigation for the top of the slope and bottom of the slope should be on separate valves.

This article is part of a year-long series inspired by the 71-page Sustainable Landscapes Program guidebook. The Water Authority and its partners also offer other great resources for landscaping upgrades, including free WaterSmart classes at

Epic Drought Means Water Crisis on Oregon-California Border

Hundreds of farmers who rely on a massive irrigation project that spans the Oregon-California border learned Wednesday they will get a tiny fraction of the water they need amid the worst drought in decades, as federal regulators attempt to balance the needs of agriculture against federally threatened and endangered fish species that are central to the heritage of several tribes.

5 Things You Need to Know About Federal Drought Aid in California

Stop if you’ve heard this before: California is in the grip of a severe drought. Again. Now the federal government is stepping in to help.  To assist California, which is the nation’s largest food supplier, the U.S. Department of Agriculture recently declared a drought disaster for 50 counties. That makes growers throughout the state who have been struggling with parched conditions eligible to seek federal loans.

Marin Municipal Water District Proposes Mandatory Conservation

The Marin Municipal Water District is proposing mandatory conservation rules for the first time since 1988 in response to record-low rainfall levels akin to those of the notorious 1976-77 drought. The proposed ordinance would require customers to limit outdoor watering to one day per week starting May 1 and adhere to other restrictions. The district board of directors plans to vote on the ordinance on April 20. The district has received just 20 inches of rain this year, its second-lowest amount in 143 years of records. The lowest was 18 inches in 1924.

City of Calistoga Issues Mandate for Water Customers to Conserve

The City of Calistoga has declared a Stage II Water emergency and starting May 1, residents and businesses will be required to conserve water. The move is a response to a recent reduction in the State’s water allocation. Citing back-to back dry years and limited precipitation in the northern part of the State, on March 23, the California Department of Water Resources reduced the State Water Project allocations for Napa County from 15% to 5%. The reduction represents a loss of approximately 25% of Calistoga’s annual demand.

An example of drought tolerant landscaping with low water use plants. Photo: Kelly M. Grow, California Department of Water Resources landscape conserve

How Much Water Can Your New Landscape Conserve?

Landscape designs using the least amount of potable water necessary are greatly encouraged in arid or Mediterranean climates like in San Diego County. It’s an important motivation for homeowners to consider efficiency and sustainability to lower water use, saving a precious resource.

Maximizing your landscaping’s ability to capture and use natural rainfall can also help reduce or even completely eliminate your reliance on potable water for irrigation.  Compare how much water your new landscape design will need against your existing landscaping’s water use. You’ll be able to estimate your future water savings.

Start by calculating the water use requirements of landscaping filled with plants that require high amounts of water, or moderate amounts, low or very low water requirements.

In these examples, evapotranspiration (ET), irrigation efficiency, and landscape area are exactly the same. The only difference: our examples are home to plants with different water requirements.

How to calculate your landscape’s water use

To calculate water use, you can refer to the San Diego Water Efficient Landscape Ordinance for guidance. Go to and search “Landscape Ordinance.” The four key variables are:

  1. Landscape Area (LA) – the square feet of area being landscaped with plants that require irrigation
  2. Evapotranspiration (ET) – this is the number in inches based on your San Diego Climate Zone
  3. Plant Factor (PF) – This is moderate, low, or very low depending on the plant selection
  4. Irrigation Efficiency (IE) – There is no such thing as a perfect irrigation system. Many factors can limit efficiency and impact your water use and the health of your plants.

Use a landscaped area of 1,000 square feet, with an ET of 51 inches annually, and IE of 0.7. Look at the big difference your plant selection can make in your water use.

Example 1: High Water Use plants (PF = 0.8) – 36,137 gallons of water per year

Example 2: Moderate Water Use plants (PF = 0.5) – 22, 586 gallons of water per year

Example 3: Low Water Use plants (PF = 0.2) – 9.034 gallons of water per year

Example 4: Very Low Water Use plants (PF = 0.1) – 4,517 gallons of water per year

From the highest estimate to the lowest estimate, you could potentially save 17,103 gallons of water every single year.

This article is part of a year-long series inspired by the 71-page Sustainable Landscapes Program guidebook. The Water Authority and its partners also offer other great resources for landscaping upgrades, including free WaterSmart classes at

Opinion: Pushing Congress to Move on Aging Water Infrastructure

The American food consumer has access to fruits, vegetables, nuts, grains and meat throughout the year. That’s largely because of Western producers and the projects that provide water to these farmers and ranchers.

Western irrigators have been dealing with changes in climate and hydrology for more than a century. But the outlook for water supplies in the future is not positive.

Opinion: As Drought Alarms Sound, is California Prepared?

We’re facing another very dry year, which follows one of the driest on record for Northern California and one of the hottest on record statewide.

The 2012-16 drought caused unprecedented stress to California’s ecosystems and pushed many native species to the brink of extinction, disrupting water management throughout the state.  Are we ready to manage our freshwater ecosystems through another drought?

Judge Rules Against Los Angeles in Long Valley Irrigation Fight

A judge has ordered the Los Angeles Department of Water and Power to continue providing historic quantities of irrigation water to lessees of its pasturelands east of Yosemite, despite the agency’s assertion that climate change is making water resources in the Sierra Nevada watershed increasingly unreliable.

Soil Microbes-your lawn-healthy soil-Conservation Corner

Remove Your Lawn the Healthy Way

The day has come to replace your thirsty, water guzzling grass. Before you remove it, plan your process carefully to leave only healthy living soil as the foundation for a beautiful, thriving new landscape.

Don’t just turn off your irrigation and let your grass turn brown as it dies off. Healthy microbes in your soil will die off along with the lawn. You want to work with those microbes to help create healthy soil for your new plants.

Instead, keep your grass moist until you remove it. It’s also a lot easier to remove fresh, moist grass than to try and pry out dead dry grass and weeds in rock hard, dry soil.

Stay cool and save healthy microbes

Remove your old turf in a way that preserves valuable soil microbes. Photo: Water Authority

Remove your old turf in a way that preserves valuable soil microbes. Photo: San Diego County Water Authority

It’s tempting to remove your lawn through solarizing. Solarizing is sometimes used as a way to remove grass without chemical treatment. Instead, a covering such as a heavy black plastic tarp is placed over the grass. Sunlight heats the covering, which broils and kills the lawn through high temperatures. This heat also kills existing healthy microbes you need for healthy soil. It’s possible to artificially replace them with compost, but you need to invest in a lot of compost to restore the good microbes when grass is killed off and removed with this method.

When soil is solarized, it’s sterilized. It remains like this for weeks. Worse, it really doesn’t do much good. Opportunistic weeds move in quickly to try and take over the ground. These weeds don’t grow from existing seeds in the soil. These have usually been killed off. But without any competition, new weeds can arrive in a flash, and nothing prevents them from taking over.

Stay loose

If you use heavy equipment to remove your old turf, the equipment’s weight will compact your soil underneath. You need to avoid this. Minimize the use of heavy equipment and use walk-behind equipment with hand tools where possible. Use a tractor or scraper only where necessary.

Avoid tilling your soil. Tilling soil breaks up and kills your soil microbes. Without the microbes, you’re guaranteed to have those weeds pop up for a long time until new soil microbes develop.

Protect your trees planted in areas where the grass is removed. The key is not to damage their roots. Heavy equipment can destroy roots established by a healthy shade tree. Steer clear of the canopy area under the tree’s branches. Its root structure extends all the way out to the drip line at the edge of the leaves. Irrigate your trees generously during the removal process to help minimize root shock.

Save landscape trees from shock

Creating a DIY self-watering bucket will help prevent landscape trees from going into shock after surrounding turf is removed. remove your lawn

Creating a DIY self-watering bucket will help prevent landscape trees from going into shock after surrounding turf is removed.

When your new sustainable landscaping is installed, your previously existing trees may go into shock when irrigation is reduced overall in your garden. While it’s one of your watersmart landscaping goals, keep the trees watered during the first year after your grass is removed.

A good way to hand water your trees: Punch holes in a five-gallon plastic bucket. Fill the bucket, and set it down at the edge of the tree canopy, and let the water slowly seep into the ground. Repeat the process three to four times to water your beautiful mature trees. This mimics the natural rainfall Mother Nature provides.

This article is part of a year-long series inspired by the 71-page Sustainable Landscapes Program guidebook. The Water Authority and its partners also offer other great resources for landscaping upgrades, including free WaterSmart classes at