Rainwater Harvesting for Drylands and Beyond by Brad Lancaster

Many thanks to Craig Mackintosh for the permission to repost a portion of his blog entry, enhanced with his own beautiful photographs, describing some of his Middle-Eastern travel experiences and the West Bank’s first PDC, which Murad Alkhuffash, David Spicer, and I just finished teaching. Visit permaculture.org.au/2010/06/30/letters-from-the-west-bank-seeds-of-hope-scattered-from-the-west-banks-first-pdc to read Craig’s blog entry in its entirety.

Letters from the West Bank – Seeds of Hope Scattered from the West Bank’s First PDC

by Craig Mackintosh June 30, 2010

The view at sunset, westwards from Marda, Palestine
All photographs © copyright Craig Mackintosh

This is now the second time I’ve had an automatic weapon aimed at me. I hope it doesn’t become a habit….

I was heading back from a short visit at a permaculture demonstration site in the Salfit district of the West Bank, via Jericho, returning to Jordan over the King Hussein/Allenby Bridge crossing. Being on a bus full of Palestinians taking the same route, I ended up funneled through the security process reserved for them instead of the usual tourist path held for non-Palestinians coming out of Jerusalem or elsewhere. The first of several stages of border control had us all off the bus to pass through a body scanner. The woman with the Galil kept it trained on the queue, reinforced with a serious look of concentration on her face. Being last in line as I collected my gear after passing through the scanner, I was the only one left to point the rifle at, so the barrel kept pace with me as I began my walk back to the bus.

Realising my vulnerability in this situation, and the tragedy of circumstances that created it, I felt a strange desire to reach into the soul of this particular soldier. This woman, at that particular moment, had me within a finger’s twitch of finalising my life, should she choose to do so – but, being a fellow human being, I still wanted to catch a glimpse of who she really was, inside.

[...]

[Here] I will … shift focus to the productive labours of Murad Alkufash towards putting his community onto a more sustainable platform, where such work has enormous potential to reduce the need for contention over land and resources, whilst inspiring others in the region – of any race, religion and creed – to do likewise.

PDC instructors (left to right): Brad Lancaster, David Spicer and Murad Alkufash

To read Craig’s blog entry in its entirety and see many more photographs of the region, the Marda site, the course, the students, and some of the work that was completed, go to: permaculture.org.au/2010/06/30/letters-from-the-west-bank-seeds-of-hope-scattered-from-the-west-banks-first-pdc

By Brad Lancaster

© 2010 www.HarvestingRainwater.com

Watergy is a term coined to describe the interconnection of water and energy. Every time we consume power we consume water. This is because water is used in the generation of our power – in Arizona this figure ranges from 0.001 to 56 gallons of water per kWh of power consumed.¹ Therefore, anything we can do to reduce our power consumption also reduces our water consumption.

Typically the amount of water consumed during power generation is much greater when the power is generated at centralized power plants, as opposed to on-site with renewable power production such as rooftop solar, whose water consumption is negligible.

Introducing a Watergy Cost Calculator for You and Your Community

How much water is expended in the generation of electricity from different sources?

How much energy, and subsequently embedded water, do average U.S. and Arizona households use per month, depending on where their energy comes from?

How about you and your community?

Use our interactive online Community Watergy Calculator to find out.

The Watergy Cost Calculator. Notice how a Tucson, Arizona, household consumes 558 gallons of water per month via its electricity consumption if it gets its power from coal (the primary source of electricity in Tucson), but consumes only 1 gallon of water per month via its electricity consumption if it gets its power from rooftop solar. Now let’s go up in scale. Notice how all Tucson households combined consume 112,161,890 gallons of water per month via their combined electrical consumption if they get their power from coal, but they would consume only 219,925 gallons of water per month via their combined electrical consumption if they were to get their power from rooftop solar. Click the image above to visit our interactive online Watergy Calculator, where you can enter the number of households in your community to generate ballpark numbers for how much water your community consumes through its power generation.

The Community Watergy Calculator was conceived of by me, and created by Megan Hartman, based mainly on watergy data for Arizona from this wonderful and succinct resource “The Water Costs of Electricity in Arizona.”

Still more watergy information can be found at www.harvestingrainwater.com/watergy-climate.

Before I speak or teach in various communities, Megan generates one-page Water Conservation and Climate Data sheets (newer versions contain additional information for site analysis and are called Patterns of Climate, Water Per Capita, Watergy, and Sun) for those communities. Many of these are available here, with more being added on a regular basis. These spreadsheets also list:

• What percentage of the community’s energy consumption is used to move (or move and treat water), or the number of average energy-consuming homes that could be powered with the energy used to pump/treat water, depending on the data we are able to obtain.

• How much rain per person per day falls on the community in a typical year (rainfall GPCD) compared to how many gallons of municipal water per person per day are consumed in a typical year (municipal GPCD). In most cases, per year, a greater volume of rain falls on the community than is provided by the municipality. This helps make the case that if the community were to harvest and utilize more of that free, high-quality rainwater, it could reduce or eliminate its depletion of local water sources, and reduce or eliminate the “need” for the high cost/high energy importation of water from elsewhere.

Patterns of Climate, Water Per Capita, Watergy and Sun for Tucson, AZ. Notice how the average Tucsonan uses 112 gallons of municipal water per day. And notice how during an average year there are 198 gallons of rain available per person per day – if only we were to harvest that rain and make it available throughout the year. To arrive at this rainfall GPCD figure, the spreadsheet calculates how much rain falls on the surface area of Tucson in a year of average rainfall, then divides that figure by 365 (days per year), and then divides the result by the population of Tucson. Also notice that 44% of the City of Tucson’s annual municipal energy consumption is used to move and treat water.

For simple and effective tips on how you can greatly reduce your energy consumption at home; increase your on-site passive heating, cooling, and solar power production; and enhance comfort and productivity, see Chapter 4 of Rainwater Harvesting for Drylands and Beyond, Volume 1. The whole book is packed with great info on how you can make progress on goals like these, while greatly enhancing the potential and use of your local rainfall, stormwater, greywater, and more.

1. Extrapolated from Water Costs of Electricity in Arizona, a Project Fact Sheet of the Arizona Water Institute (Tucson, Arizona) from a 2007 investigation by Pasqualetti & Kelley. Fact Sheet ID: AWI-07-102 Pasqualetti.

By Julia Fonseca

Whew, digging swales and basins is hard work!  Gutters and tanks are expensive.  And as the skimpy summer rains of 2009 demonstrated, how do you harvest rain when the rain refuses to fall?

Fortunately, there is a way to harvest water, even during droughts.  It costs nothing, and requires no expenditure of energy.  Can this be true?  Grab yourself a cool drink, take a seat, and let the litter fall.  Leaf and stem litter, that is.

A handful of mesquite leaf litter, delivered free of charge by the canopy overhead, can help retain water on your landscape. Photo credit: Julia Fonseca

You’ve been spending too much time raking and bagging those leaves, seed pods and twigs.  They could be working for you, if you don’t throw them out.  No, I’m not talking about composting.  Composting is work too! But if you just left the litter where it fell, it would in time form a nice natural mulch that would slow erosion, build up the water-holding ability of the soil, and help make the soil easier to dig, if you do decide to dig a swale someday.  Be a litter harvester!

Plant litter is so important that it is one of the three key measurements that the Natural Resources Conservation Service uses as a measure of watershed condition.  Plant cover, litter, and rock all help stem erosion of sloping land.  If it’s not raining, only litter and rock can retard runoff, and shade the soil, AND retain moisture.  (But see my rant against crushed rock landscaping.)

A layer of litter will work for you every time it rains well enough to penetrate the litter layer, making it more difficult for the sun to evaporate moisture from the soil below. So, if you do need to rake up litter, then consider moving it to areas where it can mulch a plant.

Even when it isn’t raining, a layer of leaf litter recruits workers to improve your soil. Unlike rock, leaf and twig litter is readily colonized by tiny organisms, and those attract others and pretty soon you have unpaid laborers tunneling into your soil, creating “macropores” for better, deeper infiltration.  In urban Tucson you can also get thrashers, cactus wrens and towhees tilling the ground and scratching for goodies!

All work together to decompose your litter into smaller pieces, and that helps pump extra carbon into the soil.  Extra carbon in your soils is part of the magic.  Soil carbon boosts the ability of the soil to hold water for later use by plants, resulting in a healthier and more drought-resistant landscape.

By Brad Lancaster

© 2010 www.HarvestingRainwater.com

Rainwater is known as “sweet water” throughout much of the world due to its pure “sweet” flavor when compared to brackish, alkaline, chemically-treated, or polluted ground and surface waters. Now it is also known as “beer water.” And folks, it is good – very good.

I sampled numerous pints of Golden Number Ale, a deliciously smooth beer made with rainwater harvested off the roof of the 5 Seasons Brewery in Atlanta, Georgia, while in town to attend the American Rainwater Catchment Systems Association (ARCSA) conference of 2009.

Rain beer

Great folks enjoying great rain beer

Drinking rain beer with wonderful Rain Harvest Systems personnel

This rain beer was a first for the brewery, and a huge success. First off, water tests found the quality of the harvested water:

easily passed all EPA requirements, and

exceeded that of Atlanta’s municipal water (link).

The soft quality of rainwater is also superior for brewing, according to 5 Seasons’ master brewer, Crawford Moran, since it contains a fraction of the dissolved minerals of harder city water. Moreover, it is excellent drinking water. I found the taste of Atlanta’s tap water disgusting, but chugged down the sweet rainwater. And soon you may be able to as well, since 5 Seasons is looking into using rainwater for all its restaurant’s table water.

Secondly, the brew resulted in a flood of glowing media attention, including coverage by CNN, and a greater public awareness of the potential of rainwater collection.

Yet 5 Season’s harvesting practices go well beyond the beer.

It reuses the waste vegetable oil from the kitchen both to boil the blend of ingredients called “wort“ used to make beer, as well as to power its fleet of greasel-fueled catering vehicles.

Collecting used cooking oil from the kitchen above in the white tank within the basement below

5 Seasons catering truck fueled by biodiesel made from used fryer oil

Some of the spent grain from the brewing process is then used to make bread served in the brewery’s restaurant. A local farmer takes the rest, composts it, and then returns the nutrients by providing the restaurant with locally grown organic produce. (Many friends and I have found the spent mash also makes a great free source of feed for chickens and goats).

Collecting the used mash from the brewing process. Used cooking oil fuels the burners cooking the batches of beer.

Chowing down on tasty spent-beer-mash bread

These practices connect/reconnect the brewery and its clientele with some of their local life cycles, resource bases, and community, while also enhancing resiliency in times of dwindling water. Atlanta gets much of its water by pumping in over-allocated Chatahoochee River water. Court battles with other communities using that water threaten to cut Atlanta off from its current take. But as long as it rains, there will be rain beer because it is made with 100% gravity-delivered rainwater collected and filtered on site.

Considering that Atlanta’s annual rainfall averages 50 inches (1,270 mm), that 5 Season’s water tank capacity is 850 gallons, and that the roof area draining to the tank is about 1,800 square feet (167 m²), brewmaster Moran figures that 5 Season’s set-up provides enough water to brew a batch of beer with every 30 minutes of rain (each batch requiring 650 gallons (2,460 liters) of rainwater.

5 Seasons' rainwater cistern below roof catchment

Roof area draining to cistern

This is a boon in both dry and wet years. In dry years the rain beer production does not strain local water supplies. And in both wet and dry years the rain collection reduces the flooding threat for downstream areas of the community during storms by slowing, spreading, and sinking the water flow higher in the watershed through local beer.

This ratchets the brewery’s efforts in the slow food movement even higher into the realm of the growing slow water movement, both of which are renowned for delicious delights that celebrate and enhance local resources in a way that is a bun dancing fun!

Sipping delicious sweet water -- harvested rain

Chugging down that delicious rainwater!

Details:

RainHarvest, a nearby locally owned business, provided 5 Seasons Brewery with all the equipment needed to harvest the rain, including 6 stages of filtration followed by dual-beam ultraviolet sterilization. The primary system components include:

• Leaf Eater preliminary leaf and debris filter

• 4″ First Flush Diverter

• Graf Optimx Pro filter

• Rainwater collection tank (existing tank is being upgraded to larger size)

• Graf 1″ floating extraction filter

• Goulds 1/2 Horsepower Pump

• SmartPress Pump Controller

• Two Full Flow 20″ Filter Units ((1) 5 micron particle filter and (1) 1 micron absolute carbon block)

• UV Pure Dual-beam UV Sterilizer

For more info on this system, water tests, and RainHarvest see:

www.RainHarvest.com/info/beer

Post-tank filtration (micron filter, carbon filter, UV light)

Pre-tank filtration

Update: April 2010
Two months after my visit to the 5 Seasons Brewery, the Fulton County Health Department shut down the production of rain beer. According to Russ Jackson of RainHarvest Systems, the Health Department had no legal ability to do so, and thus it (who?) pushed the case up the chain to the Georgia Environmental Protection Division (GEPD).  The GEPD then claimed that the rainwater harvesting system was a public water system, so 5 Seasons would need a permit to operate a public water system. But there is no infrastructure within the GEPD to address rainwater as a source for a public water system. Rather than adopt the necessary codes/guidelines /etc., the GEPD has said that this matter is out of their jurisdiction. So for right now, 5 Seasons is unable to operate their rain brew system, since the bureaucracy has not expanded its box to incorporate the out-of-the-box rainwater-harvesting – despite the fact that the harvested and filtered rainwater quality exceeds the municipal water system’s water quality.

But 5 Seasons Brewery and RainHarvest Systems are not giving up. Stay tuned for the next development.

By Brad Lancaster

© 2010 Drops in a Bucket Blog, www.HarvestingRainwater.com

When I was little I was terrified of death. I often cried myself to sleep as I thought of the end of life. It seemed so bleak, pointless, and severe.

Mom tried to comfort me with the concept of going to heaven. This did not reassure me at all. “How do you know there is a heaven?” I’d ask. “Have you been there?”

Eventually, I just numbed myself to the fear by burying it in the recesses of my mind and body.

Years later the fear evaporated with an incredible discovery – composting. Yes! Here was tangible proof that there was life after death, that everything did not just end/stop/vanish with death. Instead, things transformed. In the compost pile I saw kitchen scraps, weeds, and a dead chicken decompose into beautiful, rich, fertile soil in which earthworms, mycelia, chiles, and all kinds of new life grew.

Death no longer scared me, now it excited me. My composting dead body could generate myriad life! Don’t get me wrong: I’m in no rush to experience this. But when it eventually does happen – no problem.

Maybe.

My dead body could generate life, or more death depending on how it is disposed of.

The conventional death industry embalms bodies with a toxic brew of formaldehyde, phenol, and menthol, which can contaminate groundwater and generate cancer and other disease in those doing the embalming.¹ According to Grave Matters, today the U.S. funeral industry buries over 3 pounds of the formaldehyde-based “formalin” with every embalmed body (totaling 800,000 gallons [3,028,000 liters] of formaldehyde a year),² while from the Civil War era to 1910, arsenic, zinc, and lead where the preferred toxic embalming compounds.³

Then there are the caskets, turning cemeteries into landfills. Grave Matters states, “Over time the typical ten-acre [4 ha] swath of cemetery ground contains enough coffin wood to construct more than forty houses, nine hundred-plus tons [816,000 kg] of casket steel, and another twenty thousand tons [18,143,000 kg] of vault concrete.”⁴

A conventional cemetery

Cremation avoids embalming toxins, and the body can be burned in a shroud or cardboard container instead of a standard casket to consume less fuel and release fewer pollutants. But the fuel needed to incinerate the body is still substantial. Carbon monoxide and sulfur dioxide are typical emissions along with toxic trace metals such as mercury – which comes from dental fillings (a good reason to ask for mercury-free fillings while alive).

All crematories in the U.S. may emit 5,000 pounds [2,267 kg] of mercury a year, while in the United Kingdom four times that amount is emitted due to a higher percent of the population choosing cremation.⁵

Depressing.

Deadening.

Friend and mentor Tim Murphy gave me a different vision. He wants to be buried toxin-free and naked, ass up, in the fetal position, with an acorn up his butt. “Plant me, and plant a tree. Years later you and others can come sit under my shade, harvest some acorns, and celebrate what is possible.”

I sometimes think of Tim as a radical traditionalist, and a small, but growing segment of the death industry is enabling others to take a similar path that encourages the natural decomposition of the dead and regeneration of other life from the process rather than trying to halt or slow what will eventually happen anyway. The website www.GreenBurialCouncil.org is one conduit to this path. And the book Caring for the Dead: A Complete Guide for Those Making Funeral Arrangements with or without a Funeral Director by Lisa Carlson is another conduit if you want to reduce or eliminate your participation in a death industry.

A green burial does not allow toxic embalming, concrete vaults, or elaborate caskets, which can reduce the cost of a burial by $8,000 to $12,000, according to memorial ecologist Joe Whittaker. Young trees or an engraved fieldstone are recommended over tombstones.

I experienced a new green or conservation burial ground for all faiths first hand at Honey Creek Woodlands just outside of Atlanta, Georgia. It is a beautiful place with very caring and dedicated staff, including Joe Whittaker. And it is erupting with new life.

It is located on and beside a section of once-grazed and clear-cut forest in the heart of the 2,100-acre [849-ha] grounds of the Monastery of the Holy Spirit. The monastery grounds are bordered by and connected to a state park and the network of footpaths, creeks, and wildlife corridors of the park and encompassing 8,000-acre [2,327-ha] Arabia Mountain Heritage Area. This is a huge strength for a final resting place, since many people already feel connected to this land.

Site of old clearcut at Honey Creek Woodlands

Old clearcut site being regenerated with new growth and green burials

First and foremost, the burial grounds are a nature preserve, with the goal of enhancing a 50-year succession back to a mixed hardwood forest, through such practices as selective weeding of invasive exotics, seeding and planting native plant stock, and adding organic matter to the soil.

Bodies are planted just 3 to 3.5 feet [0.9 to 1.06 m] deep because microbial activity and soil life drops tremendously at depths greater than 4 feet [1.21 m]. Above the body the excavated soil is placed in a mound with the topsoil placed back on top for a total initial “depth” of about 5 feet [1.5 m]. This is then covered with a light pine needle mulch and native wildflower seed. The Georgia Native Plant Society ensures only natives are used. Flowers and butterflies soon cover the 2-foot [0.6-m] tall burial mound – over 64 species of butterflies were counted in one day in 2008. The mound settles completely after a few years.

Day-old green burial

Older, settled burial mound

The process is so visible! So beautiful! I visited a day-old burial; fresh flowers still atop the grave. 10 feet [3 m] away, dried and shriveled flowers rested atop a week-old burial. And as I looked about I saw I was surrounded by burials, all in various stages of settling and regeneration. The older they were, the greater the density of vegetation atop them, and the more level the soil.

I saw a family cremation plot circle of field stones surrounding a tree. All were again reunited and rooted around their family’s tree.

I felt revived just being in this regenerating forest. I felt…

Alive!

Death. Pesticide-ridden lawn above, formaldehyde-pumped bodies below within conventional cemetery.

Life. Green burial with mature forest at Honey Creek Woodlands.

REFERENCES:

1. Harris, Mark. Grave Matters: A Journey Through the Modern Funeral Industry to a Natural Way of Burial. Scribner, 2007. pp. 40, 41.

2. Harris, Mark. Grave Matters: A Journey Through the Modern Funeral Industry to a Natural Way of Burial. Scribner, 2007. pp. 40, 56.

3. Harris, Mark. Grave Matters: A Journey Through the Modern Funeral Industry to a Natural Way of Burial. Scribner, 2007. pp. 30, 39.

4. Harris, Mark. Grave Matters: A Journey Through the Modern Funeral Industry to a Natural Way of Burial. Scribner, 2007. p. 38.

5. Harris, Mark. Grave Matters: A Journey Through the Modern Funeral Industry to a Natural Way of Burial. Scribner, 2007. p. 61.

For more information about the legalities of green burials in your region, see the book Caring for the Dead: A Complete Guide for Those Making Funeral Arrangements with or without a Funeral Director by Lisa Carlson, mentioned above.

For Tucson- and/or Arizona-specific resources:

- Visit www.azgreenburial.com;

- Download AZ Green Burial FAQs, courtesy of Kristine Bentz;

- Read Kristine’s blog (which includes info on a May 2010 workshop in Prescott);

- Check out and consider joining a Tucson-based MeetUp group Kristine started which is dedicated to alternatives for death care;

- Contact Kristine by email.

Shelter for ceremonies and gatherings at Honey Creek Woodland

© 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.

© 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.

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

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.