Preparing for the next 100 years
Safety is always at top priority at IRWD. For more than 60 years, we have safely owned, operated, and maintained reservoirs and dams for the benefit of our community— even when there is an El Nino.
IRWD reservoirs near residential communities receive very little or no water from rivers or streams. That means we can completely control the flow of water in and out — like filling or draining your bathtub.
For our reservoirs that do receive water from rivers or streams, such as the Santiago Creek Dam Reservoir (aka Irvine Lake), we manage the water level during heavy rainfall by safely releasing water into our recycled water system, downstream creeks, or open spaces.
Reservoirs, which are created by dams, are important because they allow IRWD to store water locally. We monitor, inspect, and maintain our dams regularly.
But that’s not all. Our engineers and dam safety experts implement state-of-the-art Dam Safety Program Guidelines that exceed all current state standards, and even provide a roadmap for other agencies to follow. We combine traditional tried-and-true safety standards with a modern Risk-Informed Decision-Making process known as RIDM. RIDM is a rigorous, systematic and thorough approach to dam safety that identifies and reduces risks.
IRWD also pro-actively plans for improvements to ensure ongoing safety and improve efficiency. For example, in 2017, IRWD began a comprehensive assessment of its Santiago Creek Dam — built in 1933 to form Irvine Lake. The assessment determined that the dam and the outlet tower are still operational, but nearing the end of their useful life.
We are completing design of the Santiago Creek Dam Improvement Project, with construction expected to begin in the summer of 2027. The improvements will enhance those portions of the reservoir identified as needing improvements. IRWD has worked closely with the California Department of Water Resources Division of Safety of Dams, which is the official regulatory agency for dams in state, and has kept the water level at Irvine Lake lower to ensure public safety—even during large rain events.
Irvine Lake is a critical water source for 900,000 people in Orange County, and a popular recreation spot for the region. The Santiago Creek Dam Improvement Project will keep the reservoir in operation for another 100 years.
Go to IRWD.com/santiagocreekdam to learn more about the project.
Go to IRWD.com/construction/dam-safety-program for details on IRWD’s Dam Safety Program.
Independent agency recognizes IRWD lab for superior testing
When it comes to water quality testing, IRWD’s Water Quality Laboratory strives for perfection, and recent testing of IRWD’s ability proves it.
ERA, a global provider of lab proficiency testing worldwide, recently recognized IRWD’s state-of-the-art lab for its “superior quality” in water quality testing. As one of the best-equipped water laboratories in Southern California, IRWD is raising the bar in testing capabilities.
IRWD accurately tested and identified with 100% accuracy the inorganic contaminants in samples provided by ERA.
Proficiency testing requires laboratories to correctly quantify an unknown concentration of specific constituents tested to ensure defensibility and accuracy of data produced by a laboratory.
In both recent studies, IRWD lab staff tested for complex nutrients, mercury, settleable solids, trace metals, minerals, silica, turbidity, hardness, nitrite, simple nutrients, volatile solids and demand.
“IRWD leads the way in water quality testing, and we are proud to provide our customers safe, clean water every day,” said Water Quality Manager Scott Giatpaiboon. “Studies such as these are extremely precise and important. They ensure the quality of testing to protect public health.”
Successful completion of proficiency testing for all fields of accreditation is required by the State of California for all labs that test drinking water quality. IRWD’s lab is state-of-the-art and continually monitors and tests your drinking water to ensure it is safe and of high quality.
How to identify an IRWD employee
If someone knocks on your door claiming to be an IRWD employee or contractor, don’t hesitate to ask for identification.
All IRWD employees carry staff IDs with photos and are required to show them on request. Many also wear uniforms with District logos and drive an IRWD vehicle.
IRWD contractors should be able to produce information confirming they are authorized to do work in your neighborhood on behalf of the District. That work might include meter reading, construction, landscaping and temporary shutdown notifications related to new construction.
No IRWD employee or contractor will attempt to sell you a product or service. If you ever have questions, call 949-453-5330.
Student posters make a splash in annual contest
Congratulations to the winners of this year’s IRWD Water Awareness Poster Contest. These talented students created entries that highlight both their artistic abilities and their understanding of this year’s theme, “Water Connects Us All.”
—Beacon Park K-8 School: Seorin C. (sixth grade)
—Deerfield Elementary: Akshin G. (kindergarten) and Eunhu L. (fourth grade)
—Eastwood Elementary: Sophia K. (second grade)
—Jeffrey Trail Middle School: Jiwon S. (eighth grade)
—Loma Ridge Elementary: Liam I. (third grade)
—Northwood High School: Hyejun P. (ninth grade)
—Oak Creek Elementary: Jihwan K. (fifth grade)
—Orange County School of the Arts: Sophia K. (10th grade)
—Pioneer Middle School: Naelyn K. (seventh grade)
—Portola High School: Jane P. (11th grade) and Seetha V. (12th grade)
—Woodbury Elementary: Hugo I. (first grade)
All IRWD entries will advance to the next stage of the competition at the Municipal Water District of Orange County, with the opportunity to move on to the final stage at the Metropolitan Water District of Southern California.
Visit IRWD.com/postercontest to view all IRWD winners.
Ground cover plants: beautiful alternatives that thrive without a lawn
Ground cover plants replace traditional lawns with beautiful, low-maintenance surfaces that save water and skip the mower in Southern California. While traditional lawns demand constant watering, weekly mowing, and regular fertilizing just to stay green in Southern California's Mediterranean climate, ground cover plants do the opposite. They spread, they bloom, they fill in. They ask for very little and give back a landscape that feels intentional, beautiful, and unmistakably yours.
Whether you are replacing an entire lawn, filling gaps between stepping stones, or covering a slope that has always been difficult to maintain, this guide walks through the best ground cover plants for Southern California yards. You will learn which varieties handle full sun, which thrive in shade, which ones you can actually walk on, and how to plant them for success. By the end, you will have a clear plan for creating a living landscape and everything you are looking for in your Yardtopia.
Key takeaways
—Ground cover plants replace traditional lawns with living, low-maintenance surfaces that never need mowing and use a fraction of the water that turf grass demands in Southern California's climate.
—Southern California's USDA zones 9b through 10b support dozens of gorgeous ground covers that thrive on minimal irrigation, offering year-round color, texture, and even fragrance.
—The best ground cover for your yard depends on three factors: sun exposure, how much foot traffic the area receives, and the look you want to create.
What are ground cover plants and why are they better than grass?
Ground cover plants are low-growing species that spread horizontally to form a dense, continuous mat across the soil surface. They typically stay under six inches tall, require no mowing, and serve the same visual role as a lawn: creating a cohesive green (or colorful) surface that ties a landscape together. The difference is that ground covers accomplish this while using significantly less water, requiring far less maintenance, and offering far more visual interest than a single species of turf grass.
For Southern California homeowners, the case for ground covers over traditional lawns is especially compelling. Turf grass accounts for 50 to 70 percent of residential water use in this region, and most of that water goes to maintaining a front yard that the average homeowner uses less than ten minutes per week. Ground cover plants, by contrast, typically need 50 to 75 percent less irrigation once established. Many are California natives that evolved to thrive in exactly these conditions: hot, dry summers and mild, wet winters.
Beyond water savings, ground cover plants deliver benefits that grass simply cannot match. Many varieties bloom with seasonal flowers. Some release fragrance when walked on. Others suppress weeds so effectively that you spend less time on maintenance overall. And unlike a lawn, which looks essentially the same from one yard to the next, ground covers let you create a landscape with genuine character and texture.
Ground cover plants are not just for replacing entire lawns. They excel in areas where grass struggles: steep slopes, narrow strips between the sidewalk and street, shady patches under trees, and gaps between pavers or stepping stones. Starting with one of these challenging spots is a great way to experiment before committing to a larger area.
How do you plant ground cover successfully?
Planting ground cover successfully in Southern California comes down to three fundamentals: proper spacing, good soil preparation, and establishing a watering schedule that transitions from frequent to minimal over the first growing season. Get these right, and your ground cover will reward you with steady, reliable coverage.
Choosing the right time to plant
The ideal planting window for ground covers in Southern California is fall through early spring, roughly October through March. Planting during the cooler, wetter months gives roots time to establish before summer heat arrives. Fall planting is especially advantageous because plants benefit from winter rains and have a full growing season ahead to spread before their first dry summer.
If you are planting in spring or early summer, plan for more frequent irrigation during the first few months. Avoid planting in the peak of summer heat (July through September) if possible, as the stress on new transplants is significantly higher and establishment is slower.
Soil preparation
Before planting, prepare the soil by removing all existing grass or weeds. Amend the soil with two to three inches of quality compost, working it into the top six inches. This improves drainage, adds nutrients, and gives your new plants the best possible start.
For native California ground covers, go lighter on amendments. Most natives actually prefer lean, well-drained soil and can struggle in overly rich conditions. A thin layer of compost (one inch or less) is usually sufficient.
"Put some dirt in your hand and squeeze it to determine where it lies between the textures of pure clay and pure sand. You want a healthy mix of both," says Joanne Crawford-Dunér, Master Gardener, University of California Cooperative Extension Master Gardeners of Orange County.
Ground cover plants that work best in full sun
—Creeping Thyme (Thymus serpyllum)
—Kurapia (Lippia nodiflora)
—Dymondia (Dymondia margaretae)
—Lippia (Phyla nodiflora)
—Lantana (Lantana montevidensis)
Round cover plants that work best in shade
—Wild Ginger (Asarum caudatum)
—Baby Tears (Soleirolia soleirolii)
—Corsican Mint (Mentha requienii)
—Native Ferns (Various species)
Best native California ground covers
—California Fuchsia (Epilobium canum)
—Yarrow (Achillea millefolium)
—Creeping Sage (Salvia sonomensis)
—Blue-Eyed Grass (Sisyrinchium bellum)
