Harvesting Rainwater

Eight Principles for Harvesting Rainwater from Brad Lancaster.

Brad Lancaster is a permaculture expert and consultant based in Tucson. His
award-winning book Rainwater
Harvesting for Drylands and Beyond, Volume I: Guiding Principles to Welcome Rain
into your Life and Landscape
(2006, Rainsource Press) and Rainwater
Harvesting for Drylands and Beyond, Volume 2: Water-Harvesting Earthworks

are available on the web at www.HarvestingRainwater.com and at
amazon.com.
This website also contains a bounty of free information, image, video, and audio
resources.

Lancaster Residence Food Production

Link: The Oil Drum | Abundant Skies: 8 Principles for Successful Rainwater Harvesting.

Principle #1: Begin with long and thoughtful observation.
Right after we bought the house, monsoon rains poured from the sky. Rodd and I got acquainted with where where runoff pooled against the house and how the bulk of the rain ran off our site into the street. We mapped these observations, and others, including noise, head¬lights, and pollution from the street; where we wanted privacy; where we needed shade; and where we needed to enhance winter solar exposure. Wherever you direct rainwater in your landscape, you will be nurturing plant life, so take the time to make ensure this vegetation is part of your overall plan.

Next, calculate the rainwater resources available within your site’s “watershed.” For us, that area included not only the 12 inches of annual rainfall on our roof and 1/8th of an acre property, but the 20 foot wide public right-of-way adjoining our property, the section of street draining past the right-of-way, and the runoff from our neighbor’s roof. (See Table, below) This totaled about 104,600 gallons (397,000 liters) of rainwater in an average year!

Principle #2: Start harvesting rain at the top of your watershed, then work your way down.
In most cases, the top of your watershed means the roof of your house.

Our leaky
asphalt roof was a mess, so we removed it and installed 26-gauge
galvanized steel metal roofing instead, which harvests rainwater in a
potable form. However, as long as you’re only harvesting rainwater for
use in landscape irrigation, this isn’t a necessary step. (Rainwater
harvested off a conventional asphalt roof can also be made safe for
consumption with the installation of an appropriate water filtration
system.)

Take a look at your roof. Where do the gutters drain? Where is
rainfall currently being directed? This is where you should begin with
mulched water-harvesting basins and plantings (at least 10 feet from
the building’s foundation.) On our property, just under half of the
roof runoff is directed to earthworks and fruit trees north of the
house. The rest is directed to an above-ground cistern west of the
garden along our property boundary on top of a 2-foot (60 cm) high
earthen platform.

Our cistern is a custom-modified new ferro-cement septic tank, but a
number of good alternatives exist. (See, Choosing a Tank.) We selected
the location of our cistern to provide multiple functions. By placing
it on the western boundary of our yard to shadeing out the hot
afternoon sun, it creates a beneficial microclimate for our garden. By
acting as part of the property line, it provides a privacy screen from
a peering neighbor. And by placing the cistern on an elevated platform,
the system utilizes gravity in circulating water from the roof’s gutter
to the tank, and from the tank to the garden.

Whatever type of cistern you choose, having your garden located
nearby will keep hose length to a minimum (25 ft. ideal) This will
reduce water-pressure loss to surface-friction inside the hose and make
watering with rainwater a convenience. (Your plants will love it too!)

Principle #3: Always plan an overflow route, and manage overflow as a resource.
Eventually, all water-harvesting systems will meet a storm that exceeds
their capacity, so don’t get taken by surprise. All rainwater
harvesting structures should be managed in such a way that the system
can overflow in a beneficial, rather than destructive way.

In that spirit, overflow from our backyard cistern is directed via a
4-inch diameter overflow pipe gutters to a series of adjoining mulched
basins that passively irrigate a citrus tree and our garden. In
addition, all of our sunken earthworks have an overflow “spillway.”
Typically, one earthwork overflows to another and another, until all
are full and then, if needed, the lowest earthwork can overflow to a
natural drainage–-or, in a typical urban context, the street.

Your goal should be to harvest the rain, but never get flooded by it. This is key.

4. Start with small and simple strategies that harvest the rain as close as possible to where it falls.
When people think of rainwater harvesting, usually it’s cisterns and
tanks that spring to mind. But the water collected off your roof is
typically much less than what’s actually falling on your property.
Simple water-harvesting earthworks, such as basins, terraces, contour
berms, and check dams will harvest the rain where it falls, on the land.

The water-harvesting earthworks Rodd and I created collect the vast
majority of our rain. We dug level-bottomed basins and deeply mulched
them (about 4 inches) in order to infiltrate rainfall and runoff
throughout our watershed—once again starting at the highest points of
the yard and working down. Overflow water was directed from the upper
basins to the lower basins, which brings us to principle number five.

5. Spread, slow and infiltrate the flow of water into the soil.
Cisterns along with mulched and vegetated earthworks basins with
overflow routes will effectively transform your erosive runoff during
heavy rainfall into a calm, productive resource while reducing water
loss to evaporation and downstream flooding.

Raised pathways and gathering areas are also a great strategy for
spreading water through the landscape. This pattern of “high and dry”
regions that drain to adjoining basins kept “sunken and moist” will
help to define those areas through vegetation while spreading and
sinking the flow of water. (This also helps keep ice off walkways and
driveways in colder regions.) At our place, we also used earthworks to
redirect the runoff that used to pool against our house to planting
areas 10 feet or more away from the building’s foundation.

6. Maximize living and organic groundcover.
All your basins and other water-harvesting earthworks should be well
mulched and planted. This creates a “living sponge” effect that will
utilize the harvested water to create food and beauty in your
surrounding landscape while steadily improving the soil’s ability to
infiltrate and hold water due to the vast network of growing roots and
beneficial micro-organisms.

Groundcover is equally important in helping to ensure that, in your
enthusiasm for harvesting rainwater, you don’t wind up creating a haven
for mosquitoes. Mosquitoes need three days of standing water to
transform from eggs to adults. Water-harvesting earthworks allowing
water to infiltrate below the surface of the soil (typically within one
hour) where it won’t be lost to evaporation.

Take a hike in the natural unmanaged areas near your home to
determine what native vegetation would be best to plant within or
beside your earthworks. Out in the wild, you’ll notice which plants
grow naturally in depressions – they can be planted within your basins.
Wild plants preferring better drainage can be planted beside, but not
within earthworks.

Blue palo verdes, velvet mesquite, chuparosa, oreganillo, and desert
lavender are a few of the native plants found along the ephemeral
washes in our area of Tucson that we plant within our earthworks.

7. Maximize beneficial relationships and efficiency by “stacking functions.”
As mentioned previously, water-harvesting strategies offer maximum
benefits when they’re integrated into a comprehensive overall siteplan.
We focused on locating the earthworks where we wanted to stack
functions with multi-use vegetation.

Through rainwater harvesting earthworks, we’ve nurtured a solar arc
of deciduous trees on the east, north, and west sides of our home that
cool us in the summer, but let in the free light and warmth of the sun
in winter. A living fence of native plants along the property line
(along with an existing citrus tree) form part of a sun trap. This
suntrap shades our garden from the afternoon sun, creates on-site
stormwater control, and enhances habitat for native songbirds and
butterflies.

The Big Picture
Within our generative landscape, rainwater has become our primary water
source, greywater our secondary water source, and municipal groundwater
a strictly and infrequently used supplemental source (meeting no more
than 5% of our exterior water needs). Most of our established landscape
has even become regenerative by thriving on rainwater alone.

Our household consumes less than 20,000 gallons of municipal water
annually, with over 90% of that being recycled in the landscape as
greywater. Additionally, we harvest and infiltrate over 100,000 gallons
of rain and runoff into the soil of our site (and, by extension, the
community’s watershed) over the course of our annual average rainfall.

As a household, we’re shifting more and more to living within our
rainwater “budget”: the natural limits of our local environment. As a
result, we’re enriching the land, growing up to 25% of our food on
site, creating a beautiful home and neighborhood environment – and
giving back more than we take!

The further we go, the easier and more fun it gets, which brings us to the eighth and last principle:

8.  Continually reassess your system and improve it.
Three years ago, Rodd and I set up an outdoor shower so the bather
could either use pressurized municipal water at the showerhead or
cistern water distributed from a shower bucket on a hook. Other
strategies have included a solar-powered greywater “laundromat” in our
backyard (utilized by seven neighboring households) along with a
reduction in impermeable hardscape by replacing our asphalt driveway
with lush plantings and earthworks.

One of our most rewarding recent improvements has been the process
of working with our neighbors and the city to replace 26% of the
pavement from the corner intersection with a water-harvesting traffic
circle planted with native vegetation. We also succeeded in
implementing a system that harvests street runoff within curbside
mulched basins to grow a greenbelt of trees along the street and
sidewalk, so the street now passively irrigates the trees.

As a result, our neighborhood—once the victim of urban blight—is now one of the greenest and most livable areas of the city.

My advice to anyone who wants to get started living more sustainably
is to start with rainwater-harvesting. Start at the top. Start small.
But above all—start!

Sidebar: Choosing a Rainwater Cistern
Our cistern has a 1,200-gallon (4,560 liter) capacity. We selected this
size after calculating the average annual roof runoff, assessing our
water needs, and determining the resources we wanted to commit to the
system. We opted for a precast concrete septic tank for a number of
reasons, but primarily because it was affordable as well as a workable
size and shape for our space (5 foot wide, 6 feet tall, 10 feet long).

Our septic tank was custom-made for use as a cistern, and further
reinforced for above-ground installation. The cost back in 1996 was
$600, which included delivery and placement. It’s been working great
ever since.

Other options for pre-manufactured cisterns include light-free dark
green or black polyurethane plastic, corrugated metal, and fiberglass.
See www.watertanks.com for options and look in the yellow pages under tanks for local suppliers.

Calculating Your Rainwater Resources
To calculate the volume of rain falling in an average year on a
specific surface such as your roof, yard, or neighborhood, use the
following calculation: CATCHMENT AREA (in square feet) multiplied by
the AVERAGE ANNUAL RAINFALL (in feet) multiplied by 7.48 (to convert
cubic feet to gallons) equals the TOTAL RAINWATER FALLING ON THAT
CATCHMENT IN AN AVERAGE YEAR: CATCHMENT AREA (ft2) x RAINFALL (ft) x
7.48 gal/ft3 = TOTAL AVAILABLE RAINWATER (gal/year).

Green Community and Solar Homes Honor Gardener

They are rare in the South: green home builders/real estate developers. Hopefully we’ll see more of them in the future. This is a great start!

Here are some excerpts from an article in the Atlanta Journal Constitution.

Link: Residences a new definition for green community | ajc.com.

Weatherford Place in Roswell [GA] is not your usual residential community under construction.

For one thing, there are no Dumpsters on the site. There’s no need because nearly all the excess construction waste is put back to use.

From top to bottom, inside and out, Weatherford Place is developing a new definition for a green residential community. It eventually will have eight homes on 1.6 acres of land bordering Crossville Creek.

The three visionaries behind the development call it a "solar community of net-zero energy homes," built to the greenest building standards. They call their home designs EcoCraft: designed and built to nature’s code.

"This is the first of its kind," says Simone du Boise, an architect specializing in environmental design. "There’s not another neighborhood like this."

Each home is designed to a platinum LEED (Leadership in Energy and Environmental Design) level and the entire development will be platinum LEED —- the first in the United States, according to business partner Dan Downey.

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But it’s the solar power that really sets the development apart.

"Think of each one of these homes as a little power plant," du Boise says. She explains that the solar energy generated immediately gets put on the power grid. Georgia Power credits each home for the power it generates, and du Boise says design specifications show that each home will generate more power than it needs —- which is how they become net-zero energy homes.

"This home will use two-thirds less energy than the typical home," Downey says. "We are using the heat generated from the solar panels to heat the water."

One house, already purchased by an investor, has been built as a model for how the other seven homes will work. Attention was given to every detail: the location of the windows, the wood used, the carpet, the paint, the fixtures (both light and plumbing), the 1,880 gallon cistern placed underground to capture rainwater, and even a manually-operated dumbwaiter to help move groceries, meals, laundry, suitcases and other stuff from floor to floor. The list is endless.

The third visionary behind Weatherford is designer Denise Donahue. She has integrated the project’s themes and philosophy at every level.

For example, there was a "ground blessing" instead of a groundbreaking, held on the summer solstice last summer —- the day with the most light.

The first part of the development was to restore one-third of the land to green space. Workers also stabilized the embankment next to Crossville Creek to prevent runoff of dirt and containments.

Other features include a community gazebo, a back-up generator for the neighborhood in case all the power goes out and a garden overlooking the creek.

Each home will be a living laboratory, equipped with monitors and sensors to track how environmentally friendly these homes will be. Developers are partnering with Georgia Power and Kennesaw State University to collect information for energy management and efficiency studies.

Donahue, du Boise and Downey are nontraditional in another way. Their company is called Cadmus Construction, but it actually is a one-stop shop of architectural design, landscape, construction and development.

"We take ownership of doing everything to ensure the integrity of the project," Donahue says. "We don’t think the world needs another developer or builder or general contractor or even another architect. We think the world needs environmental stewards."

These homes are on the market for about $750,000 each and have 2,500 to 3,900 square feet if a homeowner desires a finished basement. According to Downey, the first home already has been appraised at $1 million.

"We are trying to prove that you can profitably build a state-of-the-art green home and sell it at market price," Downey says.

"We really do believe we can do these homes for the low-income, affordable homes so people don’t have to make a choice of heat or eat," du Boise adds.

"We’d like to start a non-profit organization to do affordable homes," says Donahue, looking to the future.

The project is named after Louis Weatherford, who originally owned the property. He was a gardener/farmer who annually would recycle seeds from vegetables and fruit he grew.

Every homeowner will receive a bag of seeds from Weatherford’s garden to continue the cycle of life. The gazebo is in memory of Weatherford’s late wife, Cora, who had always wanted one. It’s built partly with wood from the barn that used to be on the property.

Donahue says every homeowner automatically will become lifetime members of the Upper Chattahoochee Riverkeeper (she’s on its board).

Clearly, du Boise, Donahue and Downey have put their hearts and souls into this project. As du Boise said: "Right now, we have put everything we have into this."

Donahue says Weatherford Place is the culmination of their careers.

"When you believe in something, you risk everything," Donahue says. "This is the beginning of a movement. It’s about making something good happen in the world."

For more information, go to www.weatherfordplace.com.