Posts Tagged: water
In California, 40 percent of agriculture is still irrigated by pouring water onto farmland, a much less efficient practice that drip and overhead irrigation. But those numbers are changing, reported Matt Weiser on Water Deeply.
Weiser interviewed UC Cooperative Extension cropping systems specialist Jeff Mitchell about the water-saving potential of using overhead irrigation, a system that is popular in other parts of the nation and world, but only used on 2 percent of California farmland. Mitchell was the primary author of a research article in the current issue of California Agriculture journal, which said that water and money can be saved using overhead irrigation in production of wheat, corn, cotton, onion and broccoli.
Mitchell said California researchers are looking more closely at overhead irrigation because they anticipate future constraints on agriculture, including water and labor shortages. Additionally, the system is ideal for combining with conservation agriculture systems, which include the use of cover crops, leaving crop residue on the soil surface and reducing tillage disturbance of the soil. The combination of overhead irrigation and conservation agriculture practices reduces water use, cuts back on dust emissions, increases yield and improves the soil.
Weisner asked how overhead irrigation could be as efficient as drip, when people typically see "water spraying everywhere from these roving sprinklers high off the ground."
Mitchell said farmers use pressure regulators and a variety of nozzles on hoses hanging down from the system to deliver water at precisely the rate and location where it is needed through the season.
"So, they're not spraying water. These are low to the ground, and there are various delivery nozzle practices that can be used," Mitchell said.
A recent study led by UC Cooperative Extension specialist Van Butsic used high resolution satellite imagery to conduct a systematic survey of cannabis production and to explore its potential ecological consequences.
Published this spring in Environmental Research Letters, the study focused on the “emerald-triangle” in northern California's Humboldt, Mendocino, and Trinity counties, which many believe is the top cannabis-producing region in the United States.
The UC Berkeley-based Butsic and his co-author Jacob Brenner used Google Earth imagery to locate and map grow sites (both greenhouses and outdoor plots) in 60 watersheds. Most cannabis grow sites are very small, and have gone undetected when researchers used automated remote sensing techniques, which are commonly used to detect larger changes such as deforestation.
“We chose to use fine-grained imagery available in Google Earth and to systematically digitize grows by hand, identifying individual plants. Most plants stand out as neat, clear, little circles,” said Brenner, who is on the faculty of the Department of Environmental Studies and Science at Ithaca College. “The method was laborious — it took over 700 hours — but it proved to be highly accurate.”
Butsic and Brenner paired their image analysis with data on the spatial characteristics of the sites (slope, distance to rivers, distance to roads) and information on steelhead trout and Chinook salmon, both of which are listed as threatened species under the federal Endangered Species Act. These and other species are vulnerable to the low water flows, soil erosion, and chemical contamination that can result from nearby agriculture.
Results of the study show 4,428 grow sites, most of which were located on steep slopes far from developed roads. Because these sites will potentially use significant amounts of water and are near the habitat for threatened species, Butsic and Brenner conclude that there is a high risk of negative ecological consequences.
“The overall footprint of the grows is actually quite small [~2 square kiliometers], and the water use is only equivalent to about 100 acres of almonds,” says Butsic, who is in the Department of Environmental Science, Policy, and Management at Berkeley. According to Butsic, California currently has more than one million irrigated acres of almonds.
He stresses that the issue lies in the placement of the sites: “Close to streams, far from roads, and on steep slopes — cannabis may be a case of the right plant being in the wrong place.”
Last year, California legislature passed laws designed to regulate medical marijuana production, and state voters will weigh in on whether to legalize recreational marijuana this coming fall. Given these changes as well as the profitability of cannabis production, Butsic expects that marijuana cultivation will expand into other sites with suitable growing conditions throughout the region. He and Brenner assert that ecological monitoring of these hotspots should be a top priority.
Bills recently signed into law by Governor Jerry Brown have made some advances in this direction — requiring municipalities to develop land use ordinances for cannabis production, forcing growers to obtain permits for water diversions, and requiring a system to track cannabis from when it is first planted until it reaches consumers.
But the researchers say that regulation will likely be a constant challenge because it will rely on monitoring procedures that are just now emerging, as well as voluntary registration from producers and budget allocation from the state for oversight and enforcement.
“Some of the same fundamental challenges that face researchers face regulators as well, primarily that cannabis agriculture remains a semi-clandestine activity,” says Brenner. “It has a legacy of lurking in the shadows. We just don't know — and can't know — where every grow exists or whether every grower is complying with new regulations.”
The alliance aims to make plain water the easy, appealing substitute for sugary beverages – soda, energy drinks, fruit drinks, and sweetened coffee and tea drinks. The alliance is also actively working on the safety of tap water in the nation's schools and childcare settings.
“To make water the beverage of choice will require a movement,” said Christina Hecht, a member of the NPI team. “NPI will build bridges, spearhead the creation of shared resources, align messages, strategies and aims, and coordinate strong external communications.”
NPI was formed by UC Agriculture and Natural Resources in 2014 to conduct, evaluate and share research related to the impact of nutrition and physical activity on public health. The W.K. Kellogg Foundation has awarded NPI a $960,000 grant to coordinate the National Drinking Water Alliance for three years.
“Even when water is available, too many children and adults choose sugar-sweetened beverages,” said Hecht, who will serve as the National Drinking Water Alliance coordinator. “In our American diet, sugary drinks are the top source of added sugars for both adults and children, and, remarkably, they are the single largest source of calories for teens aged 14 to 18.”
But Hecht is quick to point out that if people are to make the switch to water, water needs to be easily accessible and they need to know that it is safe to drink.
High consumption of sugar-sweetened drinks is associated with obesity and other chronic health problems, such as heart disease and diabetes. UCLA scientists reported in March that the diabetes epidemic in California is “out of control.” The study says 55 percent of the state's population has prediabetes or diabetes – many of them are undiagnosed.
“Simply switching to water is a relatively easy lifestyle change that can have a big impact on the intake of added sugar and excess calories, reducing diabetes risk,” Hecht said. “It can also improve oral health.”
The National Drinking Water Alliance includes government agencies, education officials, researchers, water industries, and non-governmental organizations like the Center for Science in the Public Interest, American Academy of Pediatrics Campaign for Dental Health, and the American Heart Association. They believe by sharing knowledge, resources and connections, they will hasten progress toward their common goal.
Fortunately, the current state of safe drinking water in the U.S. is mostly favorable. About 90 percent of Americans get their water from public utilities and 95 percent of those supply safe water. In some areas, however, water can become contaminated on the path between utility and tap, typically with lead. Sometimes other contaminants can leach in through breaks in pipes.
“We all recognize that, if we are going to tell people to drink water, they need to have confidence that the tap water is safe,” Hecht said. “At the moment, we don't know the magnitude of the problem of unsafe drinking water. The alliance is highly focused on policy as the most effective tool to bring about broad change.”
The National Drinking Water Alliance plans a Congressional hearing on national drinking water and is developing best practices for effective access to safe drinking water in schools and childcare settings.
The University of California Division of Agriculture and Natural Resources (UC ANR) has appointed Soroosh Sorooshian as chair of the Rosenberg International Forum on Water Policy. Sorooshian is distinguished professor of civil and environmental engineering and earth sciences at UC Irvine.
The forum, a program of UC ANR's California Institute for Water Resources, was launched in 1996 with an endowment gift from the Bank of America honoring then-retiring bank chairman and CEO Richard Rosenberg. Experts from all over the world convene at the Rosenberg Forum to identify ways in which conflict in the management of water resources can be reduced and to promote science-based policies to govern the management of water resources.
“I'm delighted that the University of California, through the Rosenberg International Forum on Water Policy, is carrying out the vision of Richard Rosenberg in reducing conflict in water resources management through dialogue and information sharing between scientists and policymakers,” said UC President Janet Napolitano. “We are pleased that Dr. Soroosh Sorooshian, with his wide range of expertise and prominence in the international community, will be leading this important work as the incoming chair of the Rosenberg Forum.”
The forum meets biennially at different locations around the world. Previous forums have been held in San Francisco (1997), Spain (1999 and 2008), Australia (2002), Turkey (2004), Canada (2006), Argentina (2010), and Jordan (2013). The most recent forum was in January 2016 in Panama City, Panama.
“Over the past 30 years, the Rosenburg Forum has raised UC's stature in international water conflict resolutions,” said Glenda Humiston, UC vice president for Agriculture and Natural Resources. “The forum will continue to develop new approaches and solutions to addressing water problems around the world under the leadership of Dr. Sorooshian, an accomplished and brilliant scientist.”
Attendance at the forum is by invitation and limited to 50 water scholars and senior water managers. Participants devote their time at each forum to discussions of previously commissioned papers, which are published following the meeting. The conclusions and findings of each forum are also published.
“The need for approaches and solutions to securing clean, reliable water sources crosses all political, ethnic and territorial boundaries,” said UC Irvine Chancellor Howard Gillman. “But how we get to those solutions varies greatly, depending on culture, financial resources and social norms. I'm confident that Soroosh Sorooshian will be able to find ways to transcend the differences and find workable solutions for all. I'm proud that UCI can contribute to making great progress on such global issues.”
Sorooshian is also director of the Center for Hydrometeorology and Remote Sensing in the Henry Samueli School of Engineering at UC Irvine. His fields of interest include hydrometeorology, water resources systems, climate studies and application of remote sensing to water resources issues in arid and semi-arid zones. Sorooshian is a member of the National Academy of Engineering and has garnered many international and national awards for his work. His appointment was effective April 1, 2016.
“I am honored to be appointed chair of the Rosenberg Forum and serve after my dear colleague Henry Vaux Jr., professor emeritus of resource economics at the University of California Riverside, who has filled this role since the forum was established,” Sorooshian said. “I've also had the pleasure of meeting Mr. Rosenberg. He is a remarkable and humble man whose wisdom and knowledge of international issues are unmatched. I thank him for sharing his vision of the role the Rosenberg Forum can play in addressing international water issues, and I look forward to this new opportunity.”
Can you help fight the California drought by consuming only foods and beverages that require minimal water to produce?
Daniel Sumner, director of the UC Agricultural Issues Center at UC Davis, and research assistant Nina M. Anderson mine the details of this issue to help us all better understand just what impact our food choices can have on conserving California's precious water.
To begin with, not all water drops are equal because not all water uses impact California's drought, the researchers explain.
So just what water does qualify as California drought-relevant water? You can definitely count surface water and groundwater used for agricultural irrigation as well as water used for urban purposes, including industrial, commercial and household uses.
And here are a few examples of what water is not relevant to California's drought:
-- Water used in another state to produce young livestock that are later shipped to California for food production; and
-- Rain that falls on un-irrigated California pastureland. (Studies show that non-irrigated, grazed pastures actually release more water into streams and rivers than do un-grazed pastures, the researchers say.)
In short, California's drought-relevant water includes all irrigation water, but excludes rainfall on non-irrigated California pastures as well as any water that actually came from out-of-state sources and wound up in livestock feeds or young livestock eventually imported by California farmers and ranchers.
Also, the amount of water that soaks back into the ground following crop irrigation doesn't count – and that amount can be quantified for each crop.
Comparing water use for various foods
I think you're getting the picture; this water-for-food analysis is complicated. For this paper, the researchers examined five plant-based and two animal-based food products: almonds, wine, tomatoes, broccoli, lettuce, milk and beef steak.
In teasing out the accurate amount of water that can be attributed to each food, the researchers first calculated how much water must be applied to grow a serving of each crop or animal product. Then they backed off the amount of water that is not California drought-relevant water, arriving at a second figure for the amount of drought-relevant water used for each food.
They provide a terrific graph (Fig. 3) that makes this all quite clear, comparing total applied water with California drought-relevant water used for the seven food products.
Milk and steak top the chart in total water use, with 1 cup of milk requiring 68 total gallons of water and a 3-ounce steak requiring 883.5 total gallons of water.
But when only California drought-relevant water is considered, one cup of milk is shown to be using 22 gallons of water and that 3-oz steak is using just 10.5 gallons of water. (Remember, to accurately assess California drought-water usage, we had to back off rainwater on non-irrigated pastures and water applied out of state to raise young livestock or feed that eventually would be imported by California producers.)
“Remarkably, a serving of steak uses much less water than a serving of almonds, or a glass of milk or wine, and about the same as a serving of broccoli or stewed tomatoes,” write Sumner and Anderson.
Still skeptical? Check out their paper in the January-February issue of the “Update” newsletter of the Giannini Foundation of Agricultural Economics at http://bit.ly/1XKZxxC.