Follow Our Blog: The Confluence
By John Karlik, UC Cooperative Extension, Environmental Horticulture/Environmental Science Advisor, Kern County
In a previous article, I noted another dry year is underway. Excessive landscape irrigation is wasteful and can lead to turf and landscape diseases. However, rarely is it necessary to do a landscape makeover to save water, nor will modifications necessarily result in water savings.
The key to saving water outdoors is irrigation scheduling. Modifications to a landscape are of no benefit for water conservation unless the irrigation amount is reduced. Although water conservation is a large topic, here are a few tips and ideas for saving water in landscapes and other outdoor plantings:
Check the irrigation system
Periodically run the irrigation system during the day to check for leaks, missing heads, broken risers, and sprinkler coverage. Repair as necessary.
Determine how much to water
Water needs of plants in home gardens, landscapes, and orchards change by a factor of 10 from winter to summer in much of California, though the exact factor is location specific. Therefore, irrigation schedules should be changed at least four times per year: spring, summer, fall, and winter. In winter, you may be able to turn the system off completely.
Irrigation amounts are usually expressed as depth of applied water. For example, during winter in the southern San Joaquin Valley, about 0.02 inches per day are needed, while in summer the value rises to about 0.25 inches per day. These values do not mean water needs to be applied every day. Weather conditions will affect water needs of plants.
You can measure how much water your sprinklers deliver by placing cans or coffee mugs in the landscape and running sprinklers for a set amount of time. You can also estimate total landscape water use from your water bill by considering water use during winter months as the baseline indoor value, and water in addition as used outdoors. That assumes sprinklers are shut off during winter.
Finally, irrigate and monitor. In other words, check soil moisture between irrigations with a shovel, soil probe, or screwdriver, and adjust the irrigation schedule accordingly.
Determine how often to water
Irrigation scheduling is a combination of frequency (how often) and duration (run-time). As a rule-of-thumb, plan to fill the soil volume containing plant roots and then irrigate again when about half the available water has been used. Therefore, set run-times for each irrigation zone and then add or subtract days depending on season of the year.
Determine when to water
Early morning is best since wind speeds and temperature are low, and less evaporation and wind-loss occur.
What about mulches?
Mulches, such as wood chips or shredded leaves, help save water by reducing evaporation from soil.
What about turfgrass?
Turfgrass is water-thrifty if irrigated carefully. However, turf is often over-irrigated, so reducing the area of turf may lead to water savings. Experimental data show warm-season grasses, such as bermudagrass and the UC release ‘El Toro' zoysia, offer water savings over cool season turfs, such as tall fescue or bluegrass. Buffalograss is even more drought tolerant, but not often planted in California.
What about “drought-tolerant plants?”
Research-based water-use data do not exist for most plants used in landscapes. We often infer drought tolerance from seeing where a plant grows in nature. However, many California natives and plants adapted to Mediterranean climates may not perform well under irrigated conditions. These plants may be susceptible to root rot, for example, if irrigated. Drought-tolerant plants do not of themselves save water. Saving water is instead accomplished by changing irrigation schedules to reduce applied water.
By John Karlik, UC Cooperative Extension, Environmental Horticulture/Environmental Science Advisor, Kern County
As California enters another dry summer, the supply and use of water are once again becoming topics of immediate concern. Statewide, agriculture dominates use of developed water — meaning water which is moved through pipes at some point. In urban areas, about half of developed water is used outdoors, and of that fraction about half is used for landscape irrigation.
That half is an important fraction in Los Angeles and other urban areas. Across the state, homeowners may be interested in saving money on water bills, improving plant health, limiting weeds, and being ecologically responsible while still having an attractive, low-maintenance landscape.
There are several approaches to landscape management that can save water. Some are relatively simple, such as adjusting irrigation schedules. Others require more cost and time, such as replacing some plant materials with others or modifying an irrigation system.
In the 1990s, there were many meetings and attention given to the concept of xeriscape, which is a water-conserving landscape. Seven principles of xeriscape were enunciated, among them plant selection, use of mulches, and so forth. Often, when someone asks about reducing landscape irrigation, the first thought or question is about replacing plants with others thought to require less water.
The key to water savings, however, is irrigation scheduling, which is a combination of frequency and duration. That means how often the system is run and how much water is applied each time. In fact, all possible landscape modifications are directed toward being able to make changes in how much water is applied, because without reducing applied water by changing irrigation settings no water will be saved.
Around 1990, I did a case study in my own home landscape in Bakersfield, California, which is a warm-summer area, to measure how various changes in the landscape affected water use. I tracked water use through monthly water bills, and knew how much water the previous owner had used on a month-by-month basis.
When I moved in to the house, I immediately began a four-phase plan to change the landscape and evaluate corresponding water use. Goals were to conserve water, minimize maintenance, lessen the need for herbicides and insecticides, and evaluate less common plants thought to be water conserving. The house had a water meter, and I recorded the monthly values.
The first phase focused on assessing the property. The landscape had 4,880 square feet of well-maintained hybrid bermudagrass with additional areas of border plantings of annual flowers and shrubs.
Phase two involved changing irrigation scheduling with no other landscape modifications. I began by conducting a water audit by placing small containers around the yard during a watering cycle and measuring the amount of water in the containers. I used these data to determine precipitation rate; that is, how much water sprinklers delivered per given time period. Then, I checked UC data for historic reference evapotranspiration (ETo), which is the amount of water an unstressed area of cool season turfgrass uses. I adjusted the irrigation schedule accordingly.
This change – the water audit plus changing sprinkler timer settings based on ETo – was the least expensive alteration. Yet it ultimately proved to be the most effective in reducing water use, resulting in a 33% savings in outdoor water use compared to the baseline year.
In phase three, turf was replaced and the total turf area reduced. Bermudagrass was sod cut and removed and replaced with ‘El Toro' zoysia, a UC release. The main reason for turf replacement was not water conservation, at which bermudagrass excels, but rather to reduce maintenance and to observe ‘El Toro' in a residential setting, since at the time it was quite new.
The bermudagrass on the south side of the driveway was replaced with plants thought to be water conserving from an Arizona nursery. In the side yard along the street, bermudagrass between a fence and sidewalk was replaced with landscape roses watered by drip irrigation. The new turf area was 3,260 square feet, 67% of the original turf area. Water saved following these modifications was small, only 4% less than in year two.
Overall, through these modifications, water use in the landscape was reduced to 55% of its initial value. As noted, the greatest savings occurred by simply adjusting clock settings to better correspond to plant water needs. Other benefits were reduction in maintenance time and improved ease of care of the landscape.
“California's historic drought presents an opportunity to apply insight from on-the-ground managers to develop future adaptation and mitigation strategies for management and policy decision-making. Ranchers are among the first to experience the social, economic, and environmental impacts of drought, so they are essential in co-developing management and policy guidance for building rangeland resilience to drought,” says Grace Woodmansee, UC ANR Livestock and Natural Resources Advisor in Siskiyou County.
Woodmansee is relatively new to her position, having started in January of 2021, but she is not new to UC ANR. She grew up in Chico, California, raised market lambs through 4-H, and eventually earned an undergraduate degree from Chico State. As an undergraduate, she interned with UC Cooperative Extension and was drawn to how connected county advisors were to their communities.
She continued to pursue this work through graduate school. “My interest in rangeland management and Cooperative Extension expanded while serving as a research assistant in the UC Rangelands lab at UC Davis, where I completed my Master of Science in Agronomy in November 2020,” Woodmansee explains.
While conducting graduate research, Woodmansee worked with UC ANR's Dan Macon, Tracy Schohr, and Leslie Roche to analyze data from interviews of rangeland livestock producers collected near the end of California's last historic drought in 2016. The team asked 48 rangeland livestock producers about what proactive strategies they used to prepare for drought and what reactive actions they took to respond to drought. The managers then ranked the effectiveness each practice.
Through the interviews, Woodmansee and her colleagues explored whether multi-species grazing was effective as a proactive drought management strategy. Multi-species grazing means that a mix of livestock, such as sheep and cattle, who like to eat different plants, graze the land. This may allow ranchers to stretch the available forage during a drought year. The interviews revealed that multi-species ranchers managed drought in a greater variety of ways. Indeed, multi-species grazing seems to allow for greater flexibility in coping with drought.
“Surprisingly, some of the least-used management strategies were ranked as most effective by ranchers. For example, we found that multi-species grazing was the least-used proactive drought management practice, but was the highest ranked proactive practice based on perceived effectiveness by ranchers,” Woodmansee observed. As extreme, multi-year droughts become more common, strategies that were ranked as highly effective by ranchers may be the best hope for mitigating future drought impacts.
These results led Woodmansee and her colleagues to conclude that prioritizing management flexibility is the most effective way for ranchers and land managers to manage drought. “A diversity of both proactive and reactive drought management strategies will continue to be a critical component of building ranch resilience, particularly during multi-year droughts,” says Woodmansee.
As for the future, Woodmansee is excited to be a part of the Siskiyou County community and to work with ranchers and land managers to identify research priorities and projects that will not only address livestock production but also contribute to solutions for natural resource management challenges. She hopes to continue working on drought-related research, contribute to increasing wildfire preparedness, and support disaster planning for commercial livestock operators.
“It can be overwhelming to think about the effects of complex natural disasters occurring simultaneously, such as drought and wildfire, and how to support land managers as they manage through these challenges,” Woodmansee reflects, noting that Siskiyou County has been under extreme drought conditions for over a year and the impacts on forage production, irrigation water availability, and fire danger this spring are apparent to her. “But I am excited to be working with motivated and innovative folks, including ranchers, extension colleagues, agency personnel, and community members, to solve water-related challenges.”
The podcast Water Talk launched its second season on Friday, April 2. This season focuses in part on drought, a water issue at the top of many minds during this relatively dry rainy season.
"In California, drought is not 'if,' it's 'when,' said Water Talk co-host Faith Kearns, academic coordinator with the California Institute for Water Resources in the preview episode.
"The second season includes a diverse group of guests from every corner of the state, border to border," said co-host Samuel Sandoval, a UC Cooperative Extension specialist in the UC Davis Department of Land, Air, and Water Resources.
The weekly podcast will feature discussions of agriculture, water policy, environmental and social justice, land and wildlife management, water for cities, Indigenous perspectives on water, climate change, and other issues related to California water.
"We thought a lot about the geography of the state, the identities of the people whom we were speaking with, the experts we were talking with, and the topics," said co-host Mallika Nocco, a UC Cooperative Extension specialist in the UC Davis Department of Land, Air, and Water Resources.
Some aspects of the podcast were modified in the second season. Instead of recording during a live event, as was done in the first season, each episode was recorded with only the co-hosts. In addition, two production assistants, Claire Bjork and Victoria Roberts, supported the development of each episode through a UC ANR Renewable Resources Extension Act grant.
Michael Mendez is an assistant professor in the School of Social Ecology at UC Irvine, and has spent time doing public policy work as an advisor, senior legislative consultant, lobbyist, and as a gubernatorial appointee during the passage of California's internationally acclaimed climate change laws. Most recently, Governor Newsom appointed Michael to the Los Angeles Regional Water Quality Control Board, which regulates water quality in a region of 11 million people. He is author of the book Climate Change from the Streets (Yale University Press).
You've had really interesting experiences on your way to joining the faculty at UC Irvine. Can you tell us a bit more about your path and how it has shaped the work you do now?
As a scholar, my work is situated at the intersection of climate change, public health, and public policy. I am an interdisciplinary researcher, and my interests are centered on environmental justice. Many environmental hazards are disproportionately threatening low-income communities of color, and I came to this field because of my personal experience growing up in an immigrant community in Los Angeles that faced multiple environmental threats. I saw from an early age that individuals and social movements were focusing on how contamination, landfills, and bad air quality were affecting those communities. They sought to produce alternative environmental futures. That really motivated me.
I was also in a voluntary school busing program and traveled from my neighborhood towards a wealthier, white, affluent area. At a young age, I'd be up early and on the bus every day, seeing the differences between the neighborhoods I traveled through. That made me wonder why these communities looked so different. That eventually led me to study urban and environmental planning at MIT. Shortly thereafter, I was invited by my local assembly woman, Cindy Montanez, to work for her in the state capitol. She had a strong passion for environmental justice issues and was thrilled that I was from the district she represented, and that I understood the issues.
I ended up working for several years in the California legislature, and in a few other related policy positions. Eventually I wanted to continue my academic career and was accepted to the city and regional planning department at UC Berkeley for my doctoral program. I endeavored to have a stronger voice on environmental policy and justice issues. Working for politicians, I was in many ways in the seat of power and could make a lot of change, but not necessarily have as much of an independent voice as I wanted to. In addition, the environmental field tends to be pretty white and male. I wanted to be part of that next generation of thought leadership and scholarship around these issues, and serve as a role model for younger people of color.
Your book, Climate Change from the Streets: How Conflict and Collaboration Strengthen the Environmental Justice Movement, is focused on climate change and inequality. In it, you argue that local knowledge, culture, and history must be central to addressing climate change. Can you talk a bit more about this?
I come to academia as a second career, and my work emphasizes the connection between theory and practice. My research has public policy implications because I focus on real world problems facing disadvantaged communities of color. My book provides an on-the-ground view of how environmental justice groups and people of color are influencing the climate change policymaking project in California, as well as globally.
While California is often seen as a global leader on climate change, I shed light on the work environmental justice groups did to rescale the focus to include the neighborhood level, and to direct reduction strategies to the hardest hit communities. In particular, these groups have been able to transform the idea of climate change as an abstract, global challenge to one centered on local issues. We understand that burning fossil fuels creates, of course, carbon and greenhouse gas emissions, but it also emits local pollution that stays at the neighborhood level and affects people's health.
Oftentimes, environmental justice groups are framed as irrational non-experts, which is not the case. These groups have challenged California's climate change programs, improved them, and they continue to innovate. In addition, other states and countries, including our national government, are now looking toward California as they begin similar work. It took over ten years to get to a point where people of color are leading and connecting climate change to racial and environmental justice. My book is the first to tell that story.
Your current research includes drought in disadvantaged communities. Can you talk a bit about these efforts?
In my post-doctoral work, I collaborated with the Community Water Center, the leading water justice group in the state, on drought resiliency and groundwater issues. During California's last extreme drought, I was doing my field work and visited East Porterville, which was ground zero for how water injustice was hitting migrant communities, particularly undocumented Latino migrants. They had very little water, and what they had was often contaminated. At the same time, their water rates were incredibly high for what was essentially undrinkable water. This was affecting people with some of the lowest incomes in the state. The drought was exacerbating these disparities.
Based on that experience, I believe our priority should be ensuring people have safe and affordable drinking water. The human right to water is important and powerful. California is the first state to adopt it as a normative, bold statement. It doesn't yet have teeth but it's a valuable statement that can guide policy, and that is slowly happening.
You have recently been appointed by Governor Newsom to the Los Angeles Regional Water Quality Control Board. That appointment is just beginning, but can you talk a bit about what kinds of things you'll be working on?
It's a major responsibility to be on the board, which is an important regulatory body that regulates water pollution for a region of 11 million people. This is the most technical board I have ever been on. I've been on the city planning commission, on the state mining and geology board, I've advised on air quality and drought issues. But from a regulatory perspective, water is extremely technocratic and has a long federal history that is tied to how we regulate things regionally.
My goal with the board is to follow through with my history of policy and research focused on providing better opportunities for low-income communities of color, particularly those experiencing environmental injustice. The key topics I will focus on include making our water policies and regulations more inclusive and putting the needs of people of color at the forefront. I also want to move forward on thinking more explicitly about climate change and water resiliency with an equity lens.
What is most exciting to you about what you're working on now?
Right now, I'm most excited about the wildfire research that I'm doing with migrant advocacy and environmental justice groups. This is community-based, engaged work, and my project collaborators are also research partners and co-authors. I originated some of this work after the Thomas Fire in Ventura and Santa Barbara counties, where I worked with an Indigenous migrant rights group to understand the effects of fire on undocumented migrants, and to advocate for better policies. We were equal partners in terms of policy, briefings, presenting at academic and policy related conferences, and working on media campaigns.
I've now been approached by new partners to do similar work in Sonoma County – a joint project that is not extractive. Many times the research process can be extractive, where an academic comes in, collects data, time, and resources, and community groups never see it and don't get credit for telling their own story and having their own voice. This is particularly important with groups like undocumented migrants because this is a stigmatized and exploited population, and therefore my research design and approach should be different as well.