Archive for the 'Drops in a Bucket Blog' Category
© 2009 Brad Lancaster, www.HarvestingRainwater.com
Many garden hoses leach lead and other chemicals into the water as it sits in the hose. Polyvinyl chloride (PVC) and brass fittings are often the culprits.
 Yuck - the water tastes like lead! To reduce such risk, purchase, use, and/or drink only from hoses labeled safe for drinking water. Never buy any hose with such labeling as “WARNING: This product contains a chemical in the State of California to cause cancer and birth defects or other reproductive harm.” Note that such warnings will typically be in very small print.
A May 2005 Consumer Reports article, “Dare you drink from a garden hose?” reports that hoses labeled safe for drinking leach minuscule concentrations of lead into water standing in the hose, while hoses not labeled drinking water safe leached up to 10 to 100 times allowable lead levels into water standing in the hose.
So, flush any hose before you drink from it by letting the water run a while before you gulp.
Suppliers of hoses labeled safe for drinking water include:
• Gatorhyde Drinking Water Safe Garden Hose: Available in 3/4-inch diameter, but upon inspection I found that it constricts down to 5/8th-inch interior diameter.
• Armadillo Hoses: Available in 5/8-inch diameter, but upon inspection I found that it constricts down to less than 1/2-inch interior diameter – closer to 3/8-inch. For a list of their NSF-51 certified hoses, click here.
Note that these are far better than most, but not perfect. Gatorhyde contains polyurethane, while Armadillo contains a less toxic PVC. Both polyurethane and PVC are banned materials in the Living Building Challenge Materials Red List (Prerequisite Five). The Living Building Challenge is an integrated green building guide that goes well beyond LEED.
Note for anyone using gravity to move water through a hose from a rainbarrel or rainwater tank – get 3/4-inch (best) or 5/8-inch (next best) interior diameter hose instead of 1/2-inch interior diameter. The larger the interior diameter, the less surface friction will reduce your low gravity-fed pressure.
Also make sure your rain barrel or cistern faucet does not constrict its interior diameter to less than 3/4 of an inch. Look inside the valve. Unfortunately, most readily available valves reduce interior diameter to 1/4 of an inch, greatly reducing your gravity-fed pressure.
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© 2009 Brad Lancaster, www.HarvestingRainwater.com
All around the world I see water wastefully flowing down urban street curbs and out of concreted storm drains even though it has not rained in months. It is not stormwater I see flowing. It is urban drool. Others call it “nuisance runoff” – water from leaky pipes, driveway car washes, over-watered landscapes, and so on – our waste. But it can be a resource. It can be harvested.
 Urban drool running down concreted channel Tujunga Wash, Los Angeles, California. Photo credit: Brad Lancaster That is what is happening in Los Angeles, California, along a mile-long stretch of the Tujunga Wash Flood Control Channel between Vanowen Street and Oxnard Avenue. It is bringing myriad forms of life back to this community.
Between 1950 and 1952 the U.S. Army Corps of Engineers cleared a 9-mile section of the waterway of its vegetation and lined it with concrete in order to drain the water out of the community as quickly as possible. The goal was flood control, but it also dehydrated the watershed and its aquifer, removed the natural water filter, and created a fenced-off sterile blight.
 Section of Tujunga Wash and fenced-off upper bank pre-rehabilitation. Photo credit: Brad Lancaster That is now beginning to be reversed with the Tujunga Wash Greenway and Stream Restoration Project. A stream has been recreated and replanted with native riparian vegetation on the upper banks of the concreted channel. The new stream is fed by water diverted upstream from the channel through a half-mile-long pipe. Much of this water is urban drool, which flows year round. As the water flows through the greenway, it is filtered and cleaned by sand, gravel, and tree roots. Some percolates into the ground (helping recharge the aquifer); the rest is returned to the flood-control channel via another pipe. It teems with life and invites one to step off the wide pedestrian/bicycle path lining the stream to explore and play.
 Section of Tujunga Wash and new pedestrian path/corridor post rehabilitation. Photo credit: Brad Lancaster Much of this life acts as a living seed-bank for indigenous plants, whose seed can help revegetate both downstream areas as water and seed flow downstream, and upstream areas as wildlife walks and flies upstream with seed in tow.
As this life resides on the upper banks it is unlikely to be washed out in big floods. The floods will scour down the concreted channel, leaving the life in its protective upper bank eddy to replant what is scoured – and to germinate still more life not yet seen.
 Playing in section of Tujunga Wash rehabilitated upper bank stream. Photo credit: Brad Lancaster It is a small step. A beginning. An invitation to revalue and rehabilitate our waterways so they once again are regenerative corridors of water, pedestrians, and wildlife.
For more on this dynamic project see:
http://www.coastandocean.org/coast_v23_no4_2007-08/articles/tujunga_01.htm
and
http://ladpw.org/apps/news/pdf/2380_2618.pdf
For more ideas, strategies, and stories on how to harvest urban drool and rainwater runoff to generate more life higher in the watershed of our built environments see:
- Street Orchards for Community Security
- Parking Lot to Parking Orchard
- Farming in the City with Runoff from a Street
and
- Rainwater Harvesting for Drylands and Beyond, Volume 2: Water-Harvesting Earthworks
And thank you to David O’Donnell of TreePeople for guiding me to this project and its resources.
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Thanks to Julia Fonseca for this guest blog sparking up a much needed dialog on the extensive, and often excessive use of crushed rock or decomposed granite in the landscape.
By Julia Fonseca
Urban landscapes using crushed rock or “decomposed granite” (dg) are increasingly common in Arizona. Many of us native plant enthusiasts see use of crushed rock mulches as evidence that local governments and homeowners are realizing that water is too precious to be used on lawns.
 A gravel yard in Tucson, Arizona with very low diversity of plant life. Photo credit: Brad Lancaster So let’s look a little closer at the practice of using crushed rock landscaping. Where does this stuff come from? Crushed rock is mined from hills around the periphery of Tucson, Phoenix, Yuma, Prescott and other rapidly growing cities. Much of what is advertised as decomposed granite isn’t really granite. I’ve seen crushed quartzite, andesite, and volcanic rhyolite sold, in a wide array of appealing colors. Most of the mines are close to urban areas, because the fossil fuels involved in transporting the rock are a prime driver of the cost.
 Gravel mine just outside of Table Top Wilderness, southern Arizona. Photo credit: Brad Lancaster I became aware of the connection between crushed rock and urban landscaping when I found out that someone was digging into a pretty piece of desert near Ragged Top. Here was a real desert rock garden, studded with ancient ironwoods and saguaros, barrel cacti, and palo verde trees, being destroyed so people like me could create fake desert landscapes. Here, the most stable part of the natural landscape, a small outcrop which had for millenia been sloughing actual decomposed granite onto the bajada, was made into a pit that would be hopeless to reclaim during my lifetime without extraordinary use of more fossil fuels and imported materials.
I began to pay attention to what happened with the product. I saw that crushed rock and gravel “lawns” work well to reduce evaporation and conserve soil moisture. Seeds trapped by the rough surface grow up and get established in what had been barren “zeroscapes”. But often the people who apply dg to their yards do not see these new plants as a good thing. They end up applying pre-emergent sprays and herbicides to keep down the weeds.
Seldom is the life-enhancing aspect of such rock mulch being exploited to restore denuded homesites. Instead, it is used more like an aesthetically appealing bandage on an open wound. The homeowner or property manager is then locked into a cycle of grubbing out weeds and applying chemicals, and the wound never heals. Instead of having a cosmetic landscape goal, the goal should be to heal the land.
 Rock and gravel groundcovers can lead to unspoken taboos - that nothing shall hinder the view of bare rock and gravel. So, many end up blowing, raking, or vacuuming up leaf drop - strip mining nutrients and organic matter out of their landscapes. This practice can create the "need" to import synthetic fertilzers to replace the lost nutrients. Photo credit: Jenny Leis Recent research has detected heavy metals and sulfuric acids leaching out of crushed rock around Las Vegas public schools and into water (Science News: 11/15/03,p. 315). It turns out that some crushed, decorative rock is high in metal sulfides, which may be mobilized during dust storms, irrigation, and heavy rains. I’ve also begun to hear that Roundup and its active ingredient glyphosate, often applied to the dg to keep weeds down, does not break down or get immobilized in the soil as I had previously heard. Roundup can be mobilized into runoff. When dissolved in water, Roundup has been shown to have toxic effects upon fish and tadpoles.
So what is the alternative? There’s no quick and easy answer, but there are answers that use the power of plants and animals and natural energy, available to the patient person.
After we’d lived at our home for 7 years or so, the soil become much more productive of life. We don’t use imported mulch. And we haven’t even dug many swales to minimize soil and water loss. We do leave much of leaf and twig litter to decay in place, and that has helped tremendously to capture the little rain that falls. The trees and shrubs we have nurtured over the years create wind eddies, which cause a rain of leaves and dust to settle into our yard, helping to build our soil.
 A well mulched rain- and greywater-harvesting basin. Mulch is regenerated by cutting up and dropping prunings from plants within the basin. This creates a sponge that more rapidly infiltrates harvested water, while reducing soil moisture loss to evaporation. Photo credit: Brad Lancaster I enjoy the variety of dirt in my urban Tucson yard. It ranges from the calcic B-horizon near the alley to a rich humus layer, an inch thick in places, which has accumulated under the mesquite, palo verde and catclaw trees since we moved in. The curve-billed thrashers are particularly enthusiastic tillers of the soil litter, to the point where some places the weeds just won’t grow. We don’t kill off the ants, so they aerate the soil; the lizards burrow in and out of the leaf, twig and caliche pebble cover that characterizes this urban city lot.
Annual plants that come in on their own can be delightful. Whereas many native wildflowers are a bit fussy and require extra water most years, I’ve had good results in establishing and spreading a native winter annual, Bowlesia. It is a very short groundcover, with delicately attractive bright green leaves. Transplanting it is easy, and it also volunteers on the bare areas. It seems to be as aggressive as the much taller London rocket (Sysymbrium irio).
Best of all, it leaves no stiff stems behind. Plantago is also great, and grows easily from seed. In the summer, we favor the self-seeding native summer groundcovers, such as an annual grama grass, Tidestromia and Boerhavia, and hand-pull non-local, perennial ones, such as bermuda grass and buffel.
 Lightly mulched rain garden that harvests street runoff. Mulch is simply leaf drop and cut up prunings from the mesquite tree planted within the basin. Photo credit: Brad Lancaster What’s most amazing in that we have seen the development of a microbiotic crust in the front yard! It turns a dark green after a rain. Such crusts can form quickly in Arizona, if there is not too much “hoof” action. This nearly invisble network of micro-organisms holds the bare soil in place during the fiercest winds, and retards or makes difficult the establishment of new seeds. I am excited, not appalled by this “bare” dirt.
 Microbiotic crust (the dark areas on the soil) and emerging wildflowers and winter annuals in unmulched, undisturbed desert soil in southern Arizona For the quick and easy fix at home, I have to say that the use of river gravel makes more sense to me than crushed rock. Yes, it means somewhere in a floodplain a gravel pit is excavated. But rivers have much greater power to reclaim the damage than do hillslopes and rock outcrops. Even better, how about using native seeds and or cheap, locally available, organic or inorganic mulches to re-establish native plant cover? Swales, branches and other means to slow the passage of wind and water over a landscape may help. More recently, I’ve discovered the power of perennial succulent ground covers like prickly pear and agaves, and non-native aloes to stabilize the soil and provide homes for quail and lizards. Such experimentation with materials and use of energies inherent in a site can be fun and effective. Decomposed granite? No thanks.
 Gravel mine just outside Table Top Wilderness, southwestern Arizona  Rock and gravel mine just outside Table Top Wilderness, southwestern Arizona. Photo credit: Brad Lancaster  Gravel mine just outside Table Top Wilderness, southwestern Arizona. Photo credit: Brad Lancaster
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Here are some of the recommendations from the Australia delegation
touring U.S. cities to share their experiences with water efficiency as
a result of prolonged drought (from meeting 1/13/09).
1. Price water at its true value. National or Regional water initiative that regulates water – pricing, allocation and water for environment
2. Plan for rapid shifts in water loss in Colorado River basin
3. Encourage agricultural water efficiencies now to be prepared for future water restrictions
4. Create household use targets (35 gallons per person per day in most large Australian cities – compare that Tucson, AZ’s current average household water consumption of 114 gpcd)
5. Consider stormwater harvesting as another water source. Harvest street stormwater, pipe to wetland for filtration then into aquifer. To this I would add the recommendation of harvesting street runoff in street-side water-harvesting earthworks to support native, food-bearing shade trees to passively cool our communities while controlling flooding and reducing water use.
4. Unbundle water rights to have more control
5. Permanent water conservation measures not restrictions
6. Watering Time of Day restrictions
7. Set reclaimed water use goal (45% target in South Australia). To this I would add set an on-site, gravity-fed harvested greywater use goal since such systems are much less energy intensive than reclaimed water systems.
8. Rainwater harvesting requirement on all new construction
Thanks to Illene Grossman of Tucson Water for this information. The notes in italics are my addition.
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© Brad Lancaster, www.HarvestingRainwater.com
Drops in a Bucket Blog
My view of public streets was radically changed when I heard ecovillage designer Max Lindigger tell the story of an insightful walk he took with his grandfather. “Look there,” said his grandfather, pointing to condominiums being built on the once-forested slopes above his village in the Swiss Alps. “That’s where we grew and gathered food during the war. The forests were common land, a reserve of community resources. What commons remain? Where will we grow and gather our food in the next catastrophe?”
I then looked at my Sonoran desert city of Tucson, Arizona, and asked myself, “Where are my community’s forests, our commons? Where would we get our food in times of need?”
Over 450 native food plants grow wild in the intact areas of the Sonoran Desert.1 The velvet mesquite tree is one of the keystone species, producing a reliable crop of diabetes-deterring, naturally sweet, protein- and carbohydrate-rich seeds and seedpods in both wet years and drought.2 Thus it used to be a staple of the indigenous people’s diets. Yet the vast majority of these trees and the greater ecosystem have been bulldozed within my city to be replaced with a hot and inhospitable pavement of impermeable streets, parking lots and buildings or landscapes of water-hungry exotic plants dependent upon irrigation from dwindling water supplies. The pavement drains much of our scant 12 inches (305 mm) of average annual rainfall out of the community through runoff and evaporation. Yet, this pavement is also the excessively long corridor by which most of our food arrives. According to the WorldWatch Institute, the average American meal travels 1,500 to 2,500 miles (2,400 to 4,000 km) from the farm to the table.3 If oil supplies that fuel semi-trailers disappeared we’d be without food. If the power that fuels our well pumps went out, we’d be out of water. We are creating the conditions for catastrophe.
But that can change by turning “wastes” into resources, and turning challenges into opportunity. The majority of public land—our commons—in the urban setting is our public streets and adjoining right-of-ways. All too often there is little or no vegetation there, let alone a forest. But the resources (soil, local-nursery- and backyard-grown native plants, rainwater runoff, and people) to grow a forest, or at least regionally appropriate orchards, are there (figs. 24 and 25).
Once established, native food plants can survive on our natural rainfall patterns without irrigation. With harvested rainfall these plants can thrive. The vast majority of Tucson’s stormwater runoff is currently diverted straight from roofs, driveways, patios, parking lots, and convex landscapes to public streets that flood to resemble rivers; the runoff then exits via storm drains (fig. 26). If we recognize runoff as an asset rather than a liability, we can harvest it before it runs down the drain, and with it, sustainably grow native food forests on public rights-of-way along the neighborhood streets that act like ephemerally flowing riverbeds, and within public parks and on private property (fig. 27). This also greatly reduces potential flooding of downstream areas, while improving stormwater quality.
That’s a big part of the idea behind a collaborative effort in my hometown called Desert Harvesters, which strives to promote, celebrate, and enhance local food production and security by planting indigenous, food-bearing shade trees in water-harvesting earthworks, and then showing folks how to harvest and process the bounty. Annual events include neighborhood tree plantings, milling events that grind mesquite seedpods harvested from neighborhood trees into delicious flour, and native/local food feasts.
Planting Community Roots
We encourage neighborhood activists to organize tree plantings in their communities, emphasizing hardy, food-producing shade trees native to the Tucson Basin. We provide a list of the recommended trees, their description, and some of their uses on our website. These trees are the best for the area, since they have adapted over millennia to our local climate and soils, and coevolved with the native wildlife.
Neighbors can purchase these trees in 5-gallon sizes for just $8 each thanks to generous subsidies from Tucson Electric Power Company and the local program Trees for Tucson. A community tree-planting day is set for each neighborhood to distribute their trees, and it’s kicked off with a free workshop on how to plant them in water harvesting earthworks. Volunteer crews of neighborhood residents then set out to plant trees along their streets, sidewalks, and in private yards. Within hours of planting the neighborhood feels changed for the better — more neighbors know each other, the trees show the care and commitment people have for their community, and water-harvesting earthworks can be observed by all (fig. 28). Within six years of planting the trees are full and beautiful, regularly blooming with seasonal color. Neighborhoods find that as native habitat grows back within the urban core, exotic pigeon populations start to be replaced by native bird life such as cardinals, flycatchers, cactus wrens, hummingbirds, curve-billed thrashers, white-winged doves, Gambel’s quail, and Gila woodpeckers. The community’s sense of place becomes reconnected to the flora and fauna of the local ecosystem, which is becoming reestablished right outside their homes. Within eight to ten years of planting, the tree-shaded sections of the neighborhood are noticeably cooler than unplanted areas (compare figs. 29 and 30). This confirms what studies have shown — shade trees growing along streets can cool the summer temperatures of urban neighborhoods by 10°F (5.5°C) if the canopy shades enough of the hardscape.4 This can greatly reduce a community’s power consumption since less power is then needed to cool buildings mechanically. Plant a tree and you plant a living air conditioner.
Additional indigenous food trees in the Tucson area include foothills palo verde (Cercidium microphyllum) and blue palo verde (Cercidium floridum), which produce delicious flowers and barley-flavored seeds, and desert ironwood (Olneya tesota), which produces peanut-flavored seeds. Many native plants also have medicinal value and provide craft materials such as dyes, wood, glues, fiber, and more. Native food trees in other regions might include oak, pinyon pine, sugar maple, or date palm.
The Harvest
Harvesting advice is given on our website, and harvesting workshops are given in areas of the community where the trees have been planted. The harvest extends well beyond the picking of fruit and seed. We also try to teach folks to appreciate the value of harvesting the local resources that will support and enhance the trees — such as rainwater runoff and mulch. The implementation of rainwater-harvesting cisterns is encouraged to augment water-harvesting earthworks with captured roof-runoff, and enhanced water-harvesting earthworks are utilized along streets to use street runoff to irrigate passively the trees planted along the streets. This simultaneously enhances local water resources while creating a beautiful, multipurpose greenfrastructure of flood-controlling landscapes. For more information on these strategies, please see my books Rainwater Harvesting for Drylands and Beyond, Volumes 1 and 2 at www.HarvestingRainwater.com.
In addition to harvesting runoff, the basin-like earthworks passively harvest mulch in the form of leaf and fruit drop. The mulch increases the rate at which rainfall is absorbed into the soil, minimizes water loss to evaporation, and naturally fertilizes the soil. Rather than strip-mining nutrients from the trees and soil by raking away fallen leaves and fruit drop (fig. 31), we encourage folks to let this organic matter collect within the basins around the trees to decompose naturally and cycle back into the vegetation and soil (fig. 32). Prunings are cut up into 4-inch (10-cm) long sections and laid beneath the trees from which they were cut. Harvest your leaf drop and prunings, and the nutrient loop becomes regenerative. Trees grow taller and stronger.
Milling and Enjoying Mesquite
We live in a society that is often short on time and in search of convenience. Traditional means of grinding mesquite pods and processing other wild foods often demand more time than busy folks are willing to give up. So we sought to speed up the process and make it fun. Thanks to a $4,900 PRO Neighborhoods grant we were able to purchase a farm-scale hammermill and mount it to a trailer to make it mobile. We take the mill to various public, community milling events to which folks can conveniently bring their harvested mesquite pods (fig. 33). The hammermill can grind 5 gallons of whole mesquite pods into 1 gallon of finely textured, naturally sweet flour in just 5 minutes. Traditionally this would’ve taken hours (fig. 34).
The milling events are typically held in conjunction with local farmers’ markets or mesquite pancake feasts to enhance the diversity of available foods and to expose folks to the wonderful flavors and potential abundance of locally grown foods. The events are organized in October and November at community gardens, the community food bank, and community centers, to correspond with the late summer garden harvest and the end of the mesquite pod harvest. Mesquite pancakes served with prickly pear and saguaro syrups or backyard honey “plant the seeds” of the native foods’ delicious tastes and potential within the minds and palates of the hungry public (fig. 35). (Click here for a video of one of the community fiestas.) The sale of, and feasting on, local garden produce like corn, squash, tomatoes, and tepary beans, and cultural foods like tamales, sweet potato pie, and pickled cholla buds are encouraged. Local musicians play as folks eat and the hammermill is fired up to grind the mesquite pods brought by community members who harvested over the summer. Flour goes home with the harvesters, and mesquite breads, cookies, and sauces are cooked up in their kitchens.
By planting, harvesting, and sharing the produce of the native ecosystem and backyard gardens these foods become sustainable parts of our daily experience, community/cultural identity, and food security. Many of these plants, particularly the natives, do not need imported resources to grow. By incorporating such strategies as water harvesting, passive mulching, and strategic planting (such as along streets or on the east and west sides of buildings), local resources are enhanced, wildlife can prosper, neighborhoods are beautified, and communities are made more liveable. By sharing and celebrating community efforts and resources knowledge is spread, the value and appreciation of local resources grows, and community ties and investment build. All of this is an integrated means of designing to thwart catastrophe, while enhancing our lives now. And the benefits steadily grow both with the trees, the relationships we have initiated with our neighbors, and a deeper connection to place and the resources that sustain it.
Brad Lancaster is a permaculture teacher, designer, consultant, and activist living in Tucson, Arizona. He is a co-founder of Desert Harvesters. In addition, he is the author of the award-winning books Rainwater Harvesting for Drylands and Beyond, Volumes 1 and 2 at www.HarvestingRainwater.com.
The potential of harvested street runoff5
For every inch of rainfall
• A 10-foot wide paved street will drain 27,800 gallons of runoff per mile
• A 20-foot wide paved street will drain 55,700 gallons of runoff per mile
• A 30-foot wide paved street will drain 83,500 gallons of runoff per mile
For every 100 mm of rainfall
• A 3-m wide paved street will drain 300,000 liters of runoff per mile • A 6-m wide paved street will drain 600,000 liters of runoff per mile
• A 9-m wide paved street will drain 900,000 liters of runoff per mile
References:
1. Hodgson, Wendy, Food Plants of the Sonoran Desert, University of Arizona Press, 2001.
2. Niethammer, Carolyn J., The Tumbleweed Gourmet – Cooking with Wild Southwestern Plants, University of Arizona Press, 1987.
3. Halweil, Brian, Home Grown – The Case For Local Food in a Global Market, WorldWatch Paper 163, WorldWatch Institute, 2002.
4. Hammond, Johnathan, Marshall Hunt, Richard Cramer, and Lauren Neubauer, A Strategy for Energy Conservation – Proposed Energy Conservation and Solar Utilization Ordinance for the City of Davis, California, City of Davis, CA Energy Conservation Ordinance Project, 1974.
5. Lancaster, Brad. Rainwater Harvesting for Drylands and Beyond, Volume 2: Water-Harvesting Earthworks, Rainsource Press, 2008.
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Arizona has some great financial incentives for water harvesting, which other states could replicate. But more folks need to take advantage of them.
The State of Arizona will give Arizona taxpayers a one-time tax credit for a “water conservation system” (defined as a system to harvest residential rainwater and/or greywater). The credit is for 25% of the cost of the system (up to a maximum of $1,000).
Builders are eligible for an income tax credit of up to $200 per residence unit constructed with a water conservation system installed.
The credit is retroactive to January 1, 2007. So, anyone who has purchased water harvesting systems from January 1, 2007 onward can apply for the AZ tax credits until the annual amount allotted to the credit has been filled. Note: it is not too late to apply for any installations in past years done after Jan. 1, 2007 when the program began – as long as you do so before the program ends in 2012.
There is $250,000 per year allocated for these tax credits through 2012. Once all funds are used for the year you need to apply for funds in the next year, so APPLY NOW if you qualify.
More people need to apply so that these funds are both utilized and renewed after 2012. A large portion of the 2007 funds were never used, and as of early November 2008 $205,000 of the 2008 credit funds still remained in the account.
You can apply for this tax credit at:
http://www.azdor.gov/Refunds%20and%20Credits/graywaterchoicesmenu.
Specific questions about the tax credit can be directed to Rosemary Soto of AZDOR at (602) 716-6595
For more water-harvesting financial incentives around the U.S. and the world see: http://www.harvestingrainwater.com/rainwater-harvesting-inforesources/water-harvesting-tax-credits/
For water-harvesting ordinances promoting water harvesting in Tucson, Arizona (such as mandating greywater-harvesting stubouts in all new home construction, and commerical developments providing at least 50% of their irrigation needs with harvested rainwater) see:
http://www.harvestingrainwater.com/rainwater-harvesting-inforesources/rainwater-harvesting-ordinances/
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 Shade trees planted in a basin cut on contour in a once-solid asphalt parking lot. The speed hump (at the far end of the basin) acts as a diversion berm directing additional runoff into the basin. Photo taken three years after trees planted. Note: Mulch would further enhance the water infiltration and storage capacity of the basin. Photo credit: Dan Dorsey People get comfortable with, and inspired by, new ideas (such as water harvesting) when they experience working examples first hand. Your home site can present such an opportunity. Though a truly public site can maximize potential exposure, while sustaining privacy for yourself. Help turn a problem into a solution, and the idea can really take off.
Water harvester Dan Dorsey saw such an opportunity in the Tucson, Arizona Community Food Bank’s sun-baked asphalt parking lot in the 1990s. The lot was bleak, impervious, and contributed to significant flooding problems downslope when the rains came and all the stormwater rapidly ran off. Dan drew up a plan, presented it to the director, and got the go ahead.
A bunyip water level and spray paint was used to mark contour lines in the parking lot and around the building. Appropriate locations for infiltration basins were marked where they fit with contour lines, parking spaces and vehicular access. Heavy equipment precisely cut and removed the asphalt where marked, and dirt was excavated to form the basins. Then fifty 15-gallon (56-liter) sized low-water-use, food-producing mesquite trees were planted. Asphalt speed humps were installed to divert more runoff into the basins and slow parking lot traffic.
After one year, the trees could survive entirely on runoff from the building and remaining asphalt (Fig. 1). After three years some trees were 20 feet (6 m) tall. This greatly decreased the energy bills for cooling the building, and decreased stormwater flooding the street. The wavy shapes and cool green of the trees softened the sterile lines of the office building and created a pleasant and welcome place for people to park, work, and visit. Surrounded by an urban forest, people’s mood and demeanor seemed to relax.
Seven years later the Food Bank moved to a larger facility. The property was left vacant for years, yet the trees continued to grow, thrive, and inspire.
Resources:
• “Rainwater Harvesting for Drylands and Beyond, Volume 2: Water-Harvesting Earthworks” by Brad Lancaster. www.HarvestingRainwater.com
• Water-Harvesting Parking Images. http://www.harvestingrainwater.com/imagesvideoaudio/image-gallery/water-harvesting-parking/
• Mesquite pods as food. www.DesertHarvesters.org.
• “Swaling a Parking Lot in Tucson” by Dan Dorsey, Permaculture Drylands Journal, Number 30, Summer 1998, p 16.
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by Brad Lancaster, Drops in a Bucket Blog, www.HarvestingRainwater.com, copyright 2008
The following is one of my favorite water-harvesting stories. It comes from one of my mentors, Russ Buhrow, and has inspired me in much of my work. It is amazing what Russ produced with stormwater, something too many people consider to be a waste or a liability, but as Russ shows, is actually a great resource.
In summer 1980, plant sciences graduate student Russ Buhrow decided to take a break from the books to gain “hands-on” knowledge by dryfarming in the middle of the simmering desert city of Tucson, Arizona, where annual rainfall averages 12 inches (304 mm). Taking his cue from the ancient traditions of indigenous Tohono O’odham, Russ raised his crops solely on direct rainfall and runoff harvested from short bursts of sporadic summer monsoon rains. Yet Russ’s situation was somewhat different from his Native American neighbors. He didn’t farm alluvial flats of a healthy desert ecosystem where runoff from surrounding mountains flows down a braiding arroyo to a field. Instead, he farmed a semi-urban vacant lot between a dry riverbed and cinder block apartment buildings. Rather than intercepting runoff from low desert mountains and foothills, Russ learned to harvest runoff from rooftops, yards, parking lots, and a city street.
Russ began by observing the gradually sloping arable vacant lot. Wheel ruts crisscrossed it. Random piles of compacted debris were strewn about, and dense weeds grew in depressions where rainwater and organic matter collected. “Ah ha!” thought Russ. “The weeds grow where the water is, so that’s where my garden will go!”
With permission from the landowner he dug several 8- x 8-foot (2.4- x 2.4-m) sunken garden beds where the weeds grew tallest. Berms stretched to either side on the downslope side of his basins like open arms of a big welcoming hug for rainwater runoff (see Fig. 11, after article, for the multi-year progression of Russ’ fields). He planted seeds as the summer storms rolled in. Thunder cracked, lightening flashed, and the rain came down in sheets. Russ stood in the middle of it all and watched. He saw water pool in the garden basins. He also noticed water pouring off a parking lot just upslope of the basins and quickly dug a ditch as a diversion swale, directing runoff from parking lot to garden.
After 40 minutes the rain stopped. With the soil now saturated, his seeds germinated in just 3 to 5 days. Russ was full of adrenaline. As he says, “When you see the rain flow like that, it’s a EUREKA moment. You see the water and realize, this really works!” The parking lot ditch had just increased his water resources five-fold. He went right to work, expanding his planting area to 700 square feet (65 m²).
From then on, no matter how far away he was, Russ always ran to the garden when rain started to fall. “It’s amazing how much water you can catch in neighborhoods,” he says. “You just need to watch the sheet flow when it rains.” Rain and runoff revealed the land’s subtle slopes and depressions. He saw how much water flowed and where. Then he figured out how to catch and use it.
For Russ this was a rush – like playing “flood” in a huge sandbox, with lightening! The unlocked car was always nearby so he could leap in when the lightening struck too close.
By fall, drought-hardy tepary beans, black-eyed peas, corn, squash, and devil’s claw (a fiber plant with edible seeds and okra-like immature fruit) were harvested–all irrigated only by rain (Figs. 1, 2, 3).
In winter the fields went fallow, but Russ stayed active. Once, standing in the rain, he saw excessive runoff rushing down Columbus Boulevard, an asphalted arterial street that dead ended 400 yards (360 m) from his garden. “FREE WATER!” Russ yelled. He dug a 1/4-mile (0.8 km) long diversion swale/ditch from the street to his garden (Fig. 4A and Fig. 4B). He reworked the old garden beds and added new ones. When finished, the garden basins ranged from 100 to 700 square feet (9-63 m²) each. Together they resembled a series of stepped terraces that directed overflow water from the upper gardens to the lower gardens (Figs. 5, 6, 7, 8). The combined planting area was now 1/2 acre (0.1 ha).
That summer two big storms flooded the long swale with water 8 inches (20 cm) deep and 2-3 feet (60 – 90 cm) wide. Both storms lasted less than an hour and made Russ run through the garden, euphoric from the water, terrorized by lightening, and exhausted by effort. With the diversion swale running above (upslope of) the top of the terraced garden basins, Russ could temporarily divert the flow into a specific field by cutting an opening in the swale’s berm, then blocking the water’s flow within the swale at a location just downslope of the cut, to force more flow into this field. He created this “blockage” by throwing wads of weeds and brush into the swale and packing them down with his shovel, his feet, and rocks, then piling dirt behind the brush. Next, he’d run down the swale to the next field, and make a new cut in the berm and a new barrier just downslope of it. Running back up to the first diversion Russ would wait until the first field was well watered, then remove the original barrier of weeds, rock, and soil, and use this material to plug the cut in the berm so the water flowed down the main swale again. That done, he’d run down the swale to make sure the second cut and barrier were diverting water into his second field. If all was well, he’d dash off to the next field for another diversion cut and barrier. And so on, until the water stopped flowing.
Russ estimates he was harvesting as much as 2-3 acre-feet of runoff water a year. That’s 653,400 to 980,100 gallons, or 2,970,000 to 4,455,000 liters. “You had to be there when it rained, and haul ass!” Russ explains. “All could be over within 30 minutes of the first raindrop.”
Russ was passionate about harvesting water, but he made sure he didn’t collect more than could infiltrate into the soil. If water sits on the soil’s surface for more than two or three days it can activate a denitrifying bacteria (caused by a lack of oxygen in the soil), which can decrease soil fertility. Yellow spots in fields where water ponds for several days indicate denitrification. Russ prevented such problems by spreading water throughout the landscape, improving the soil’s water-absorbing capacity with organic matter and vegetation, and having adequate spillways for overflow water.
As surplus water overflowed from his fields and moistened the soil beyond and below his gardens, Russ expanded his garden by constructing new sets of terraced fields, each with raised berms to retain overflow water from the fields above (fig. 11). He soon had a full acre (0.4 ha) cultivated with corn, tepary and lima beans, Mixta and Moschata squash, devil’s claw, watermelon, sunflowers, cow peas, and, in a wet fall and winter, I’itoi onions and artichokes (Figs. 12, 13, 14).
Just two decent summer storms, spaced well apart, were enough to support his crops. Russ planted hardy heirloom seeds of dryland crops in coordination with the first good summer rain (see Notes 1 and 2 at end of article). He harvested runoff from rainfalls as light as a tenth of an inch.
Only once in five years did Russ’s fields fail. The rains just wouldn’t cooperate. They were too little, spaced too close together, or too far apart. But when they did cooperate the fields were very productive. One year, he harvested 2 tons of mature squash along with another ton of calabacitas (immature squash) – 400 lbs (180 kg) picked on one day alone. Harvests of 17,000 devil’s claw (the young fruits are eaten like okra, the dried fiber is used for traditional basket making) in a good season were common.
Russ had no money for tractors, pumps, pesticides, or water. But he also had no debts since he took no loans. Working with natural cycles his only significant investment was his time. Russ describes those times as some of the happiest of his life.
For 10 years Russ farmed within the sprawling city of Tucson, relying solely on runoff from desert rains for water. He did not contribute to groundwater depletion and provided a lot of fresh produce for his family, friends, and neighbors. He was connected with the natural elements–”If you’re not, you fail,” he says. For Russ, this connection was perhaps the greatest benefit of his work, making him feel rooted, part of the natural flow of wind, rain, and sun. Through daily observation he gained numerous insights into the cycles of the Sonoran Desert.
Russ is rarely concerned about food these days. He knows he can grow it – even in the low desert. “All you need is rain,” he says, “and we have enough.”
Enough, that is, if we recognize and value it.
In 1990 Russ went to the Cape Verde Islands, off West Africa, where he used his experience as a reference for part of a USAid study of the islands’ forms of agriculture and diversity of locally adapted food crops. After 3 months he returned and took a full-time job as grounds curator at Tohono Chul Park, where he has created a number of water harvesting features – including the Jardin Sin Aguas. Russ gives presentations on water harvesting and has a private consultation and design business.
 Fig. 1. Rain-irrigated cowpeas. Photo courtesy of Russ Buhrow  Fig. 2. Rain-irrigated tepary beans. Photo courtesy of Russ Buhrow  Fig. 3. Rain-irrigated squash. Photo courtesy of Russ Buhrow
 Fig. 4A. Diversion swale - dry. Photo courtesy of Russ Buhrow
 Fig. 4B. Diversion swale full of captured runoff. Photo courtesy of Russ Buhrow  Fig. 5. Runoff irrigated gardens. Roof runoff from building in the background is caught in the diversion swale, and directed to the gardens. Photo courtesy of Russ Buhrow  Fig. 6. Runoff flowing from upper terraced garden to a lower garden. Christopher City apartment buildings in the background. Photo courtesy of Russ Buhrow  Fig. 7. Harvested runoff flowing from an upper field to a lower field. Photo courtesy of Russ Buhrow  Fig. 8. Spillway from upper field to lower field stabilized with rock. Photo courtesy of Russ Buhrow  Fig. 9. Watershed or catchment for Russ' farm. North-south road, left of apartment complex is Columbus Blvd. East-west road above apartments is Ft. Lowell. Dotted line through Christopher City apartment complex represents ridgeline of subwatershed draining toward Columbus Blvd and Russ' diversion swale. Area in rectangle is enlarged in next figure. Rillito river bed is at the bottom (or north end) of the drawing. Illustration by Silvia Rayces  Fig. 10. Close up of Russ' farm (bottom right), parking lot and it's diversion swale draining to farm, and drainage ditch directing Columbus Blvd runoff to farm. Illustration by Silvia Rayces  Fig. 11. Multi-year progression of Russ' farm from a single garden bed in upper left corner to a 1-acre farm in lower right corner. Dark, wide lane appearing in 4th progression, represents the diversion swale and its expansion. Illustration by Silvia Rayces  Fig. 12. Russ standing in field. Photo courtesy of Russ Buhrow.  Fig. 13. Child in a bountiful field of cowpeas. Photo courtesy of Russ Buhrow  Fig. 14. Kids in fields of squash and devil's claw. Photo courtesy of Russ Buhrow NOTE 1: SOURCE OF DRYLAND-ADAPTED FOOD CROP SEEDS
Native Seeds/SEARCH, 526 N. Fourth Ave., Tucson, AZ 85705. www.nativeseeds.org.
NOTE 2: SPACING PLANTS TO STRETCH SOIL MOISTURE AND BUFFER WINDS
Russ spaced his plantings according to how much moisture was in the soil, the ability of the plants to withstand strong winds, and the expected size of plants at maturity. Spring plantings were spaced further apart than summer plantings, since the plants had to survive on residual soil moisture until the summer monsoons. Plants that were easily blown over or snapped by the wind, such as tepary beans and corn, were planted in clusters to support one another. By using wide spacing that took into account the plants’ size at maturity, Russ had easy access for weeding between plants with his roto-tiller and could avoid the use and expense of herbicides.
Tepary beans were planted in groups of 5 seed, each group 4 feet (1.2 m) apart.
Squash seeds were planted in clumps with three seeds each, with clumps spaced 8 feet (2.4 m) apart, or just 4 feet (1.2 m) apart if planted late in the growing season, since they wouldn’t get as big before frost hit).
Devil’s claw seeds were planted in clumps of three seeds, each 8 feet (1.2 m) apart.
Plants can be spaced closer if soil is deeper and can infiltrate more water. A silt/loam is good for this, while sand is often too porous. Heavy to medium clay soils can work, but watch the percolation rate. Most roots and nutrients will be in the top 2 to 4 feet of the soil.
NOTE 3: HOW MUCH RAINFALL PRODUCED HOW MUCH PRODUCE?
In 1981, Russ planted seeds at the end of March after the danger of frosts had passed. He germinated the seeds on residual soil moisture from February storms that dropped 1.02 inches (25.9 mm) of rain, and another 2.1 inches (53 mm) of rain in March. The plants got an additional 3.6 inches (91 mm) in April, and 0.45 inches (11 mm) in May. Although this was a wet year for the desert, the plants had to survive without any more water for over a month and a half. In July the rains started again, with 2.71 inches (68 mm) falling that month, 0.26 inches in August (6.6 mm), 0.47 inches in September (11.9 mm), and no rain in October. On that rainfall alone, the garden produced 9 tons (8.1 t) of Mixta squash per acre and 26,000 devil’s claw along with corn, watermelon, tepary beans, and sunflowers.
NOTE 4: THE LOSS OF ARABLE LAND
Russ Buhrow’s runoff farm no longer exists. It has since been built over with a new housing development. Houses built within the floodplain upon some of the area’s most fertile soils. If we keep building on, and paving over, our best agricultural land – where will we grow our community’s food?
NOTE 5: POTENTIAL CONTAMINANTS IN STREET RUNOFF
I think more research is needed in the area of street runoff toxins, and where they end up. Russ tells me he experienced no problems on his farm or with his produce grown a 1/4 mile from the road itself. I have never had any problems with plant health where plants have been irrigated with street runoff. The plants have thrived. In street-side, street runoff harvesting basins I harvest the fruit from the plants irrigated with street runoff, but I make sure none of the fruit has come into direct contact with the street runoff. Thus I harvest fruit from trees (mesquite pods, desert ironwood seeds, olives, pomegranates, etc). I do not grow leafy green or tuber crops in these basins. More info on my experiences can be found in
NOTE 6: MORE RESOURCES
• Rainwater Harvesting for Drylands and Beyond, Volume 1: Guiding Principles to Welcome Rain into Your Life and Landscape by Brad Lancaster. www.HarvestingRainwater.com
• Rainwater Harvesting for Drylands and Beyond, Volume 2: Water-Harvesting Earthworks by Brad Lancaster. www.HarvestingRainwater.com
• Water-Harvesting from Low Standard Rural Roads by Bill Zydeek. www.QuiviraCoalition.org
• “Street Orchards for Community Security” found at the bottom of the webpage http://www.desertharvesters.org/pressvideostories/
Posted in Drops in a Bucket Blog | 2 Comments »
Hey Harvesters,
Welcome to my new blog, “Drops in a Bucket.”
I call it “Drops in a Bucket” because it represents a celebration of those wonderful little efforts that lead to great things. In the beginning those small efforts often seem like little more than a drop in a bucket. However, this is great if they’re drops in the bucket of abundance. With enough drops we’ll fill the bucket! A drop in a bucket is a problem only if it’s a drop in the wrong bucket – the bucket of scarcity.
This blog will focus generally on the harvests of water, sun, soil, community, and food that help fill that bucket of abundance regeneratively. Good food is key to bringing good people together. To grow that food we need water, sun, soil, and those wonderful people. My intent is to create a party of ideas and examples to inspire and challenge. My hope is that it will help plant many seeds to enhance good efforts already in the works and to influence positive change on the local level, simultaneously affecting the global.
I plan to update this blog at least once a month, but depending on the harvest, it may happen more often. I hope you like it.
- Brad
Posted in Drops in a Bucket Blog | Comments Off
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