Roof-to-Garden: How to Irrigate with Rainwater
By Brian Barth
The average American household uses about 320 gallons of water per day, a third for irrigation and other outdoor uses. Collecting the water flowing down your downspouts in rainstorms so you can use it to irrigate in dry periods is often touted as a simple way to cut back. But setting up a functional rainwater irrigation system—beyond the ubiquitous 55-gallon barrels under the downspout, which won't irrigate much more than a flower bed or two—is a fairly complicated DIY project.
If you live in a townhouse or apartment with a tiny yard, one of those store-bought barrels will probably do the trick. In that case, there's not much to know—most come with instructions and all the hardware you need. But if you're planning a more ambitious project consider the following pointers before getting started. Before you begin, make sure that rain harvesting is legal in your area.
Calculating Your Water Budget
To give you an idea of how much water you have at your disposal for irrigation, here is a simple equation for figuring out how many gallons your roof sheds when it rains:
roof size (in square feet) X annual rainfall (in inches) X .6
There are rain tank calculators online so you don't have to do the math, but here is an example. If you lived in a modest 20' by 30' house (measure roof size as the length times the width of the house) in a modestly wet region with 40 inches of annual rainfall, that's (20 X 30) X 40 X .6 = 14,400 gallons. Here's a handy web tool to find out how much rainfall you get in your area each year.
In a very dry climate where most of the rain falls in winter, as is the case along most of the West Coast, you could easily use that much irrigation water in spring, summer, and fall—and much more, depending on the size of your garden. But if you live an area that typically gets rainfall throughout the warm parts of the year (plants rarely need irrigation in the winter), how much water you can catch in a year is not as relevant as how much you'll need during a summer dry spell.
Irrigation needs vary considerably depending on climate, shade, soil type, and vegetation type, but this equation will give you a rough idea of your garden's water demand:
area to be irrigated (in square feet) X maximum number of weeks between major summer rainstorms X .5
If you have a modest 30' by 30' yard and want to have enough water to irrigate for a month-long dry spell (light rain doesn't count—at least one inch of precipitation is needed to saturate the soil in dry conditions), which is not uncommon in most of the country (except in the Southwest and on the West Coast, where dry spells last many months), that's (30 X 30) X 4 X .5 = 1800 gallons.
In arid regions like Los Angeles or Phoenix, where eight months can pass between major rainstorms, the equation looks like this (30 X 30) X 32 X .5 = 14,400 gallons. So you can see why it makes sense to focus on how much you can actually collect from your roof in such climates, rather than how much you can use.
Sizing the System
The size of your rainwater catchment system may ultimately depend on your budget and how much space you are willing to dedicate to it. Rainwater is typically stored in polyethylene (plastic) tanks, which can be purchased at farm supply stores or shipped from online suppliers like The Tank Depot and Plastic-Mart. Most tanks cost roughly 50 cents per gallon of storage, though the larger sizes are often much pricier.
Larger tanks are also very unwieldy to install and are an eyesore in the landscape. A 15,000-gallon tank, for example, is roughly 12 feet in diameter by 18 feet tall and weighs more than 3000 pounds. Most people who want to store that much water opt for three 5000-gallon tanks, which are roughly 10 feet in diameter by 10 feet tall and weigh 800 pounds—light enough for a few strong people to push around and maneuver into place. Most folks in urban areas prefer to stick with 1000-gallon size tanks (6 feet in diameter by 6 feet tall and around 200 pounds), or smaller.
Finding a Location
Tanks are typically positioned at or near a downspout so the water can be funneled in directly. Rain tanks aren't pretty, so you'll probably want to situate them out of sight, or conceal them with a trellis, shrubbery, or other enclosure.
One option to prevent an eyesore next to your house is to collect water in small barrels at the downspouts, and then pump the water into a large central tank located away from the house. Another option is to bury rain tanks near the house—in this case, they'd be considered cisterns—and let the water flow from the downspouts through buried drain pipes and into the tanks. Typical polyethylene tanks may not be used underground, though specially designed underground tanks are available (they cost two to three times as much as aboveground tanks, however).
Of course, you can also collect water from the roofs of barns, sheds, and other outbuildings, which may offer better opportunities to conceal the tank than positioning it next to your house. Keep in mind that each downspout only drains a portion of the roof, so match tank size to roof area accordingly. Where you have several downspouts along one side of a house or outbuilding, it's possible to combine the flows into a single tank.
Rain tanks are extremely heavy when full of water (water weighs about 8 pounds per gallon), so you need to create a firm base for them to rest on; otherwise, the earth below may settle under the weight and cause the tank to shift.
First, remove the topsoil and then spread a 6-inch layer of gravel or granite fines to create a pad for the tank, grading the surface flat and smooth and tamping it (with a manual tamper for small areas, or a power tamper for large installations) to prevent the material from settling. Building codes typically require a 6-inch concrete slab to be poured as a base for tanks 5000 gallons in size and larger.
Next, you'll need to route the downspouts to the openings on top of their respective tanks. Simply cut into existing downspouts above the height of the tank and use a combination of "A" and "B" style elbows and lengths of downspout (a selection of gutter supplies is available at any building supply center) to reroute the downspout to the tank. Use a carpenter's level to ensure that horizontal sections of downspout are sloped "downstream" at a minimum ratio of ¼-inch per linear foot.
Here are a few recommended accessories to place between the top of the downspout and the opening of the tank:
- A self-cleaning filter to divert sticks, leaves, and other debris from the downspout.
- A tank screen to prevent smaller gutter debris from washing into the tank, and to keep mosquitoes and rodents out of the tank.
- A first flush diverter to divert the first bit of water from each rainfall, which may contain bacteria from dead insects, lizards, rodents, snakes and other critters that sometimes end up in gutters, as well as bird and animal droppings, chemical residues and fine particles from roofing materials, and anything else that might wash of your roof that an irrigation system is better off without.
All rain tanks have an overflow outlet near the top of the tank that should be connected by drain pipe to the drainage system that the downspout previously flowed into.
Connecting to the Irrigation System
Your irrigation system may be as simple as a hose connected to the valve at the bottom of the rain tank. Of course, this gravity-powered approach only works if the area you're irrigating is lower in elevation than the water level inside the tank.
Sprinklers and drip irrigation systems are likely to require a pump to provide sufficient water pressure unless the tank is significantly higher in elevation than the area to be irrigated. Each foot of elevation results in .43 pounds per square inch (psi) of water pressure. Drip systems generally require at least 15 psi (35 feet of elevation), while most sprinkler systems require at least 30 psi (70 feet of elevation).
There are a variety of pumps and pump accessories available to pressurize your irrigation system with water from a rain tank, but unless you have serious plumbing and electrical expertise, you're better off hiring an expert for this part. Setting up an effective pumping system depends on the specific context of your water storage and irrigation system; there are many technical details to be aware of to make sure you get the pressure you need, minimize electricity consumption, and avoid wearing out your (expensive) pumping equipment prematurely.
For automated irrigation systems, it's possible to tie the pump to the irrigation control box, so when each irrigation valve opens according to its schedule, the pump kicks on and provides water from the tank.
Reposted with permission from our media associate Modern Farmer.
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Google's New Timelapse Shows 37 Years of Climate Change Anywhere on Earth, Including Your Neighborhood
Google Earth's latest feature allows you to watch the climate change in four dimensions.
The new feature, called Timelapse, is the biggest update to Google Earth since 2017. It is also, as far as its developers know, the largest video taken of Earth on Earth. The feature compiles 24 million satellite photos taken between 1984 and 2020 to show how human activity has transformed the planet over the past 37 years.
"Visual evidence can cut to the core of the debate in a way that words cannot and communicate complex issues to everyone," Google Earth Director Rebecca Moore wrote in a blog post Thursday.
Moore herself has been directly impacted by the climate crisis. She was one of many Californians evacuated because of wildfires last year. However, the new feature allows people to witness more remote changes, such as the melting of ice caps.
"With Timelapse in Google Earth, we have a clearer picture of our changing planet right at our fingertips — one that shows not just problems but also solutions, as well as mesmerizingly beautiful natural phenomena that unfold over decades," she wrote.
Some climate impacts that viewers can witness include the melting of 12 miles of Alaska's Columbia Glacier between 1984 and 2020, Fortune reported. They can also watch the disintegration of the Pine Island Glacier in Antarctica. The changes are not limited to the impacts of global warming, however.
Moore said the developers had identified five themes, and Google Earth offers a guided tour for each of them. They are:
- Forest change, such as deforestation in Bolivia for soybean farming
- Urban growth, such as the quintupling of Las Vegas sprawl
- Warming temperatures, such as melting glaciers and ice sheets
- Sources of energy, such as the impacts of coal mining on Wyoming's landscape
- Fragile beauty, such as the flow of Bolivia's Mamoré River
However, the feature also allows you to see smaller-scale change. You can enter any location into the search bar, including your local neighborhood, CNN explained. The feature does not offer the detail of Street View, Gizmodo noted. It is intended to show large changes over time, rather than smaller details like the construction of a road or home.
The images for Timelapse were made possible through collaboration with NASA, the U.S. Geological Survey's Landsat satellites and the European Union's Copernicus program and Sentinel satellites. Carnegie Mellon University's CREATE Lab helped develop the technology.
To use Timelapse, you can either visit g.co/Timelapse directly or click on the Ship's Wheel icon in Google Earth, then select Timelapse. Moore said the feature would be updated annually with new images of Earth's alterations.
"We hope that this perspective of the planet will ground debates, encourage discovery and shift perspectives about some of our most pressing global issues," she wrote.
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By Asher Rosinger
Imagine seeing a news report about lead contamination in drinking water in a community that looks like yours. It might make you think twice about whether to drink your tap water or serve it to your kids – especially if you also have experienced tap water problems in the past.
In a new study, my colleagues Anisha Patel, Francesca Weaks and I estimate that approximately 61.4 million people in the U.S. did not drink their tap water as of 2017-2018. Our research, which was released in preprint format on April 8, 2021, and has not yet been peer reviewed, found that this number has grown sharply in the past several years.
Other research has shown that about 2 million Americans don't have access to clean water. Taking that into account, our findings suggest that about 59 million people have tap water access from either their municipality or private wells or cisterns, but don't drink it. While some may have contaminated water, others may be avoiding water that's actually safe.
Water insecurity is an underrecognized but growing problem in the U.S. Tap water distrust is part of the problem. And it's critical to understand what drives it, because people who don't trust their tap water shift to more expensive and often less healthy options, like bottled water or sugary drinks.
I'm a human biologist and have studied water and health for the past decade in places as diverse as Lowland Bolivia and northern Kenya. Now I run the Water, Health, and Nutrition Laboratory at Pennsylvania State University. To understand water issues, I talk to people and use large datasets to see whether a problem is unique or widespread, and stable or growing.
An Epidemic of Distrust
According to our research, there's a growing epidemic of tap water distrust and disuse in the U.S. In a 2020 study, anthropologist Sera Young and I found that tap water avoidance was declining before the Flint water crisis that began in 2014. In 2015-2016, however, it started to increase again for children.
Our new study found that in 2017-2018, the number of Americans who didn't drink tap water increased at an alarmingly high rate, particularly for Black and Hispanic adults and children. Since 2013-2014 – just before the Flint water crisis began – the prevalence of adults who do not drink their tap water has increased by 40%. Among children, not consuming tap has risen by 63%.
To calculate this change, we used data from the National Health and Nutrition Examination Survey, a nationally representative survey that releases data in two-year cycles. Sampling weights that use demographic characteristics ensure that the people being sampled are representative of the broader U.S. population.
Racial Disparities in Tap Water Consumption
Communities of color have long experienced environmental injustice across the U.S. Black, Hispanic and Native American residents are more likely to live in environmentally disadvantaged neighborhoods, with exposure to water that violates quality standards.
Our findings reflect these experiences. We calculated that Black and Hispanic children and adults are two to three times more likely to report not drinking their tap water than members of white households. In 2017-2018, roughly 3 out of 10 Black adults and children and nearly 4 of 10 Hispanic adults and children didn't drink their tap water. Approximately 2 of 10 Asian Americans didn't drink from their tap, while only 1 of 10 white Americans didn't drink their tap water.
When children don't drink any water on a given day, research shows that they consume twice as many calories from sugary drinks as children who drink water. Higher sugary drink consumption increases risk of cavities, obesity and cardiometabolic diseases. Drinking tap water provides fluoride, which lowers the risk of cavities. Relying on water alternatives is also much more expensive than drinking tap water.
A4: Choosing to drink fluoridated tap water over sugar-sweetened beverages to quench thirst is vital to protecting… https://t.co/3tm8wuWjeZ— Oral Health Watch (@Oral Health Watch)1600795750.0
What Erodes Trust
News reports – particularly high-visibility events like advisories to boil water – lead people to distrust their tap water even after the problem is fixed. For example, a 2019 study showed that water quality violations across the U.S. between 2006 and 2015 led to increases in bottled water purchases in affected counties as a way to avoid tap water, and purchase rates remained elevated after the violation.
The Flint water crisis drew national attention to water insecurity, even though state and federal regulators were slow to respond to residents' complaints there. Soon afterward, lead contamination was found in the water supply of Newark, New Jersey; the city is currently replacing all lead service lines under a legal settlement. Elsewhere, media outlets and advocacy groups have reported finding tap water samples contaminated with industrial chemicals, lead, arsenic and other contaminants.
Many other factors can cause people to distrust their water supply, including smell, taste and appearance, as well as lower income levels. Location is also an issue: Older U.S. cities with aging infrastructure are more prone to water shutoffs and water quality problems.
It's important not to blame people for distrusting what comes out of their tap, because those fears are rooted in history. In my view, addressing water insecurity requires a two-part strategy: ensuring that everyone has access to clean water, and increasing trust so people who have safe water will use it.
As part of his proposed infrastructure plan, President Joe Biden is asking Congress for $111 billion to improve water delivery systems, replace lead pipelines and tackle other contaminants. The plan also proposes improvements for small water systems and underserved communities.
These are critical steps to rebuild trust. Yet, in my view, the U.S. Environmental Protection Agency should also provide better public education about water quality testing and targeted interventions for vulnerable populations, such as children and underserved communities. Initiatives to simplify and improve water quality reports can help people understand what's in their water and what they can do if they think something is wrong with it.
Who delivers those messages is important. In areas like Flint, where former government officials have been indicted on charges including negligence and perjury in connection with the water crisis, the government's word alone won't rebuild trust. Instead, community members can fill this critical role.
Another priority is the 13%-15% of Americans who rely on private well water, which is not regulated under the Safe Drinking Water Act. These households are responsible for their own water quality testing. Public funding would help them test it regularly and address any problems.
Public distrust of tap water in the U.S. reflects decades of policies that have reduced access to reliable, safe drinking water in communities of color. Fixing water lines is important, but so is giving people confidence to turn on the tap.
Asher Rosinger is an assistant professor of biobehavioral health, anthropology, and demography and director of the Water, Health, and Nutrition Laboratory at Penn State University.
Disclosure statement: Asher Rosinger receives funding from the National Science Foundation on an unrelated project. This work was supported by the Ann Atherton Hertzler Early Career Professorship funds, and the Penn State Population Research Institute (NICHD P2CHD041025). The funders had no role in the research or interpretation of results.
Reposted with permission from The Conversation.
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A new report promoting urgent climate action in Australia has stirred debate for claiming that global temperatures will rise past 1.5 degrees Celsius in the next decade.
Australia's Climate Council released the report on Thursday. The council is an independent organization of climate scientists and experts on health, renewable energy and policy who work to inform the Australian public on the climate crisis. But their latest claim is causing controversy.
"Multiple lines of evidence show that limiting global warming to 1.5°C above the preindustrial level, without significant overshoot and subsequent drawdown, is now out of reach due to past inaction," Dr. Kevin Trenberth of the National Center for Atmospheric Research and Prof. Christopher Field of the Stanford Woods Institute for the Environment wrote in the foreword. "The science is telling us that global average temperature rise will likely exceed 1.5°C during the 2030s, and that long-term stabilization at warming at or below 1.5°C will be extremely challenging."
The report is titled "Aim high, go fast: Why emissions need to plummet this decade," and as the name suggests, it is ultimately concerned with urging more robust climate action on the part of the Australian government. The report calls for the country to reduce emissions by 75 percent by 2030 and reach net zero by 2035 in order to achieve the long-term goals of the Paris agreement, which means limiting warming to well below two degrees Celsius.
"The world achieving net zero by 2050 is at least a decade too late and carries a strong risk of irreversible global climate disruption at levels inconsistent with maintaining well-functioning human societies," the authors wrote.
The report further argues that global temperatures are likely to exceed 1.5 degrees Celsius in the 2030s based on existing temperature increases; locked-in warming from emissions that have already occurred; evidence from past climate changes and the percentage of the carbon budget that has already been used.
The report isn't a call to give up on the Paris agreement. It is possible that global temperatures could swell past 1.5 degrees Celsius but still be reduced by removing carbon dioxide from the atmosphere. Even if temperatures do exceed 1.5 degrees, every degree of warming that can be prevented makes a difference.
"Basically we can still hold temperature rise to well below 2C and do that without overshoot and drawdown," Will Steffen, lead report author from the Australian National University's Climate Change Institute, told Australia's ABC News. "Every tenth of a degree actually does matter — 1.8C is better than 1.9C, and is much better than 2C."
However, some outside scientists question both the accuracy and effectiveness of the report's claim. Both Adjunct Professor Bill Hare from Murdoch University and Dr. Carl-Freidrich Schleussner from Humboldt University told ABC News they have been trying to contact the Climate Council about its 1.5 overshoot claim for months. They said that it went against other major reports, including the UN Environment Program Gap Report and the recent Intergovernmental Panel on Climate Change Special Report on 1.5˚C.
"The big challenge their report reinforces is the need for urgent action to get on that 1.5C pathway, [so] it's very paradoxical to me that they've chosen to attack that target," Dr. Hare told ABC News.
However, Scientist Andy Pitman from the Center of Excellence for Climate Extremes at the University of New South Wales told The Guardian that the report's assessment was correct.
"It's simply not possible to limit warming to 1.5C now," he said. "There's too much inertia in the system and even if you stopped greenhouse gas emissions today, you would still reach 1.5C [of heating]."
However, one aspect everyone agreed on involved the importance of lowering emissions as soon as possible.
"[There is] absolute fundamental agreement on the task at hand, which is to get emissions to plummet," Simon Bradshaw, report author and Climate Council head of research, told The Guardian.
French winemakers are facing devastating grape loss from the worst frost in decades, preceded by unusually warm temperatures, highlighting the dangers to the sector posed by climate change.
"An important share of the harvest has been lost. It's too early to give a percentage estimate, but in any case it's a tragedy for the winegrowers who have been hit," said Christophe Chateau, director of communications at the Bordeaux Wine Council, told CNN.
Climate change, caused by the extraction and combustion of fossil fuels, has pushed winegrowing seasons earlier, putting crops at higher risk of cold — and wildfires supercharged by climate change also threaten American vignerons and farmworkers as well.
"I think it's good for people to understand that this is nature, climate change is real, and to be conscious of the effort that goes into making wine and the heartbreak that is the loss of a crop," Jeremy Seysses of Domaine Dujac in Burgundy's Côte de Nuits told Wine Enthusiast.
As reported by Wine Enthusiast:
Last week, images of candlelit French vineyards flooded social media. Across the country, winemakers installed bougies, or large wax-filled metal pots, among the vines to prevent cold air from settling in during an especially late frost.
With temperatures in early April as low as 22°F, and following an unseasonably warm March, this year's frost damage may be the worst in history for French winegrowers. Every corner of France reports considerable losses, from Champagne to Provence, and Côtes de Gascogne to Alsace. As a result, there will likely be very little French wine from the 2021 vintage reaching U.S. shores.
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Climate change could make it harder to find a good cup of coffee, new research finds. A changing climate might shrink suitable areas for specialty coffee production without adaptation, making coffee taste blander and impacting the livelihoods of small farms in the Global South.
Published in Scientific Reports on Wednesday, the study focused on regions in Ethiopia, Africa's largest coffee-producing nation. Although studies have previously documented the impact of climate change on coffee production, what's less understood is how varying climates could change the flavors of specialty coffee, the researchers wrote.
The team aimed to fill this gap. Their results provide a glimpse into how future climate change could impact local regions and economies that rely on coffee cultivation, underscoring the value of local adaptation measures.
Researchers analyzed how 19 different climate factors, such as mean temperatures and rainfall levels, would affect the cultivation of five distinct specialty coffee types in the future, the Potsdam Institute for Climate Impact Research (PIK) reported. Although researchers found that areas suitable for growing "average quality coffee" may actually increase over time with climate change, regions where specialty coffee is grown will shrink — a pending problem in light of the global demand for high-quality coffee.
"This is an issue not just for coffee lovers, but for local agricultural value creation," Abel Chemura, the study's lead author, told the PIK.
Coffee profiles rely on specific climate patterns for their unique flavors, levels of acidity and fragrances. But in a warmer climate, the coffee cherry — the fruit picked from a coffee plant — matures faster than the bean inside, making for a lower quality cup of coffee, the PIK reported.
For example, the sought-after Yirgacheffe variety of coffee, which is cultivated in southwestern Ethiopia, could lose more than 40 percent of its suitable growth area by the end of the century, PIK reported. This could impact small farms and threaten Ethiopia's economy, the researchers noted.
"If one or more coffee regions lose their specialty status due to climate change this has potentially grave ramifications for the smallholder farmers in the region," Christoph Gornott, co-author of the study, told the PIK. "If they were forced to switch to growing conventional, less palatable and bitter coffee types, they would all of the sudden compete with industrial production systems elsewhere that are more efficient." In a country where coffee exports account for nearly a third of all agricultural exports, "this could prove fatal," Gornott added.
Climate change impacts on coffee production are not unique to Ethiopia. In Columbia's mountainous coffee-growing regions, temperatures are warming by 0.5 degrees Fahrenheit every decade, according to Yale Environment 360. Extreme levels of precipitation, which are becoming more common, also impact production, as they spread insect and fungal diseases.
"In earlier times, the climate was perfect for coffee," one small farmer in Columbia told Yale Environment 360. "In the period of flowering, there was summer. During harvest, there was winter. But from 2008 onward, this changed and we now don't know when it will be summer, when the coffee will blossom."
But researchers say there are glimmers of hope, emphasizing the importance of local adaptation measures that are designed for particular climates and communities. For example, in regions where temperature is an important factor for specialty coffee cultivation, the researchers suggest improved agroforestry systems that could maintain canopy temperatures, a promising step toward sustaining the "availability and taste of one of the world's most beloved beverages and, more importantly, on economic opportunities in local communities of the Global South," Gornott concluded.