Abundant Skies: 8 Principles for Successful Rainwater Harvesting

The following is a guest post by Brad Lancaster on rainwater harvesting. Energy scarcity and water scarcity are closely related phenomena, especially in certain parts of the world. While rainwater harvesting is no panacea for our water or energy problems, it may be a critical component in many regions for dealing with issues of scarcity. It is also an excellent example of a scale-free tool: it can be implemented by individuals, communities, or nations.





Food produced from rainwater on Brad Lancaster's Tucson residence

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 http://www.harvestingrainwater.com/ and at amazon.com. This website also contains a bounty of free information, image, video, and audio resources.

My interest in water -harvesting arose from a desire both to reduce my cost of living and to be part of the solution rather than the problem in my desert city of Tucson, Arizona. One of Tucson’s biggest problems is its mismanagement of water resources, pulling more each year from the water table than nature can replace. This is a practice that has dried out the Santa Cruz river, killed countless springs and wells, and severely depleted available groundwater resources.

Living in the desert has put a special emphasis on water -harvesting for me, but it’s a valuable strategy for non-desert environments, too. Rainwater harvesting is effective for reducing or preventing erosion and downstream flooding while improving stormwater quality. Thus, Portland and Seattle have embraced water-harvesting to protect salmon populations, and Maryland is doing the same to protect the Chesapeake Bay. And anywhere in the world, water -harvesting is a smart strategy for helping to recharge groundwater tables, springs, wells, and rivers.

Back in 1994, my brother Rodd was also interested in water-harvesting, but as long as we were both renting, all we could do was read up on the subject. At the time, we were both self-employed, making what the government considers poverty wages. No bank would touch us. On our own, neither of us could afford to purchase a home, but together, it was feasible. (It helped that the house we wound up purchasing was about to be condemned.) We did 95% of the renovation work ourselves and used mainly salvaged materials.

Twelve years later, our property value has shot through the roof. The integrated water-harvesting techniques Rodd and I learned and implemented on this once-barren urban lot have transformed it into an oasis in the desert, with temperatures ranging an average ten degrees lower than our neighbors’. Our land produces 15-25% of our food, which includes organic, homegrown fruits, nuts, vegetables, eggs, honey, and mesquite flour grown solely with rainwater and greywater (reclaimed household wash-water.) Our utility bills have been dropping steadily since we moved in and now run an average $20 per month.



The Lancaster residence before renovation in 1994



2006, after renovation: rainwater and greywater utilized for food production, climate control, privacy.

In the course of creating our sustainable oasis here in Tucson, Rodd and I arrived at eight basic principles that anyone can use to implement a successful rainwater-harvesting strategy of their own.

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!



Enjoying a shady right-of-way produced by rainwater-irrigated, food-producing trees at the Lancaster residence

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 http://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)

Good stuff. In thinking about the future, keep in mind that when oil goes, so too do replacements for this plastic piping. Thus get the kind that lasts a long time. Keep some extras in the basement, and figure on how to do this without much pipe, maybe terra cotta or stuff made out of wood. And Keep It Simple Smarty: KISS :)

keep in mind that when oil goes, so too do replacements for this plastic piping.

you can recycle plastics.

"you can recycle plastics." No, I can't unless I develop a process that uses machinery, petrochemicals, and a good bit of fossil energy. Have you seen the size of the extruding equipment to make PVC pipe?

If there is a manufacturer, without transportation, I won't be able to get re manufactured plastic piping from afar. PVC pipe is durable and resistant to the sunlight. Stuff that is home made will not last long. Peak Oil means things will change and won't be so easy, and often not possible. Better to prepare by thinking of the difficulties ahead, rather than glossing over things and saying we can do it. In the long run most of this manufactured stuff will be gone. Plan ahead.

No, I can't unless I develop a process that uses machinery, petrochemicals, and a good bit of fossil energy.

you can't, but society at large can. just look how many plastic bottles we recycle.

The quantity of post-consumer plastics recycled has increased every year since at least 1990. In 2006 the amount of plastic bottles recycled reached a record high of 2,220,000,000 pounds. The amount of PET bottles recycled in 2006 increased more than 102 million pounds compared to 2005. HDPE bottle recycling increased in 2005 to 928 million pounds. All plastic bottles were recycled at a rate of 24 percent in 2005.

http://en.wikipedia.org/wiki/Plastic_recycling

right now PVC is not recycled much but only because it is not cost effective. once it is that will help.

http://en.wikipedia.org/wiki/PVC#Recycling

and just how are those plastic bottles recycled, that is by what energy?

and just how are those plastic bottles recycled, that is by what energy?

I don't know specifically. fossil fuels are involved, but it takes a lot less energy to recycle plastic than to make it from scratch. there is probably no reason why we can't use wind, solar and hydro in lieu of fossil fuels when the need comes.

Polyethylene terephthalate may be pressure-cooked with methanol, and the monomers recovered in methylated form. This represents a savings over making new ethylene glycol and terephthalic acid. The process does require some chemistry, of course.

As far as I know, PETE is the only manmade polymer which is recoverable in this manner. Other plastics can only be "downcycled" into higher-entropy materials such as road surface, wood substitutes, or fuel. And PVC pipe is downright nasty as fuel (phosgene, dioxins and such...)

You might learn to grow your own irrigation pipes.
http://www.learnnc.org/lp/multimedia/1731

Metal roofing is not cheap, we paid $2.53/sq foot for materials to cover our 560 sq ft Greenhouse shed, and another $600 for installation. In any event, we installed the metal roofing to support our solar photovoltaic panels and for rainwater collection as a secondary use.

"Metal roofing is not cheap"

Good fire protection in wildfire areas.

great article, brad.

utilizing the cistern as a heat sink is probably not an option in your case, but rigging a heat exchanger inside the house and another in the cistern wouldn't be that great a challenge with a burried cistern. do you use a swamp cooler?

these are the kind of low-tech solutions that i think will save us.

where i live, the city charges for storm water run-off, based on the total sf of buildings and pavement. afaict they are offering no encouragement for harvesting.

and, i am assuming that you planted deciduous trees on the west,SOUTH, and north. this is a fundamental, forgotten principle of landscaping. the first thing that is usually done in a suburban development is to remove ALL the trees.

Very nice post! Even though I have two good shallow wells on my property, one of them only eight years old, a good high water table, and decent yearly rainfall, I have been researching putting in a medium sized rainwater collection system for potable water consumption. The wells I use exclusively for agricultural use and fairly soon for my washing machine and toilets (composting toilets are too expensive). My drinking water is from a private provider and expensive. Even the most stringent water consumption I still have a minimum fee to pay, one I would like to eliminate as I further reduce my income. My house roof is an asphalt one, but my pole barn is metal so it is a perfect candidate for water collection. I have also been considering putting in a small pond in a ravine on the north side of my property, but I’ll have to test to see if the rainfall is sufficient to fill it; I suspect it is as many in my township have homemade ponds. Any experience with the black plastic cisterns? I was thinking of putting one on a six foot high platform so I can have decent water flow.

Siwmae (Hiya) Bruce!

My composting john consists of three containers in a small compartment: a bucket to sit on (tall and capacious, with comfortable seat); a smaller bucket containing variable mixes of sawdust, dry soil, forest floor duff, and wood-ash, and a pint-volume scoop (throw in one scoopful after each sit-down); and finally, for liquids, a gallon plastic can on a cord, to hold it suspended at standing dick level.

That's it. Cost? Can't be much, Mostly I scavenged and improvised. (My semi-detached partner lives in her own house with a flushing john, all very orthodox and dainty -- for now....)

All solids and liquids at my place are caught, mostly separately, though that's not absolutely crucial, but keeping the liquid out of the solids bucket helps to keep the smell of the whole john sweet and foresty. All the products of my john go back, via composting systems, to my permaculture ground. Fatal phosphate bottleneck? What bottleneck!

I admit that I've not yet solved the problem of converting women to this system -- and maybe hyper-fastidious men. But the average male shlub can cope with it without a thought. With women, it's not the technical matter of separating the liquids from the solids as they sit which is problematic. That technique has been solved very ingeniously, and can be seen in action at the place of a friend of mine at Fachwen, Arfon, Gwynedd, Cymru Gogledd (North Wales to English-speakers), Britain. Google 'Cae Mabon' and then look for the 'Loo with a view' page. This splendid structure serves several hundred visitors a year, of both sexes, and works faultlessly, without any flush water whatever. No, the problem with women is the matter of -- perhaps too much -- fastidiousness, encouraged by our unsustainable hitech lifestyles right now in the over-prosperous (for a short while longer) West. But that will adjust, I think, perforce.

Incidentally, this post contrasts starkly with the techno-optimist eega-beeva chat over on yesterday's guest post by Bill James. Guess which post strikes me as most persuasive........

But I suppose that future reality will -- with luck -- be some unguessable blend of the two approaches, plus other serendipity that we can even guess at the moment.

Thanx for the reply and the info! I used to collect my urine via a homemade urinal years ago and I need to get back to doing that. It was great for kicking my compost during the winter. I’m thinking of installing a urinal on the wall and plumbing it to a collection barrel where there is a slope on the south side of the house. I’d kind of like to have a crapper that would be a little more sophisticated than a bucket or require a separate building with two holding areas (the minute I would build a separate structure the assessor would raise my property taxes). If anyone knows where there are plans or blueprints for a composting toilet system that uses no or little energy, either on the web, magazine, or in book form I would greatly appreciate the info. Not using my Norweco septic system for processing feces would greatly reduce the aeration requirements in the processing tank.

It's not strictly "composting," but take a look at the Sunny John mouldering toilet system.

Also, the classic Humanure Handbook is available to read free online.

Jeff beat me to it. I've lent a paper copy of Jenkins' book to a dozen people. All were skeptical (as was I), now hold graduate degrees (whatever that's worth), and accepted the practicality and safety of Jenkins' system after reading the book. Four of the twelve have put the system to practise.

I may or may not have used the composting toilet system described in Jenkins' book for the last four years. The possible experience may have led me to the conclusion that the system described is simple, cheap, nearly fool-proof, and except for a few minutes while dumping buckets into the compost bin, stink-free. No need to seperate liquids from solids either. Just do your business and cover with a scoop or two of sawdust.

I may or may not have experience with the syste, but my wife most certainly has not (but she's fine with a commercial composting toilet that is in the works for the house we're building).

"I was thinking of putting one on a six foot high platform so I can have decent water flow"

Not sure what you mean by "decent flow rate", but I put a 500 litre tank on a 6ft platform in the vegetable garden to improve the water flow rate. I shouldn't have bothered. I then did what I should've done in the first place and calculated the height necessary to give a decent flow rate. IIRC to get 2bar pressure the tank needed to be something like 17 meters high. Doh!

In my case, the old saw - "Too great haste leads us to error" - is yet again proved correct :(

Thank you for the advice.

If two people can do something like this in tuscon it just shows how many resources even places like the desert are. places like phoenix can save water and they can tap the sun for power. this places may be a lot more sustainable than people think.

This article points out something too few many of us talk about. The use of "old" technology versus new technology. Growing up as a kid, we had a cistern which my mom used to water her massive garden. It only seemed normal back then & when you think about it, why do we let rainwater run away.

And that "old" technology doesn't need to stop there. My mom is a quirky old lady, doesn't trust the "food system". She preserves food to this day and when she was younger much of Sept & Oct was spent canning things. That included making our own ketchup & salsa. She insisted I learn these skills because some day I might need them and it looks like she might be right. We had what was known as a "fruit cellar" where we put all this stuff & it stayed was always cool...no electricity needed. We also had a windmill which had a motor which produced airflow. The hose went into a pond and in winter, the windmill stopped the pond from freezing..& was home to hundreds of trout, which we ate.

I work with a charity in South America in a shanty town. The residents are incredibly poor, but most of them have a cistern on the roof of their shack. The water collects, the sun heats it up & it's how they have hot water (warm climate 12 months a year).

For really good up-to-date info on small/medium/large water storage tanks for both above ground and below (cisterns) see Art Ludwig's book "Water Storage" at
http://www.oasisdesign.net/index.htm

Also some good info on greywater systems there.

For us non-desert dwellers that sometimes get too much water in our yards, I have written a guide to installing yard drainage systems and French Drains. It is on my website at
http://www.easydigging.com/Drainage/Garden_Drainage_Guide.html

Greg in MO

Fascinating article, it reminded me of a visit to Bermuda where they have a real shortage of freshwater, and so rely on the collection of rainwater into cisterns. The technique they use with natural rock tiles for the roof was described on This Old House.

Great article.
I've been using a simple rain water collection system for our chicken coop this summer. We are in NJ. It collects rainwater from the gutters and stores it in a 55 gallon blue plastic barrel. At the bottom of the barrel I put a 1/2" hose connection and the water goes to a gravity fed waterer.
But I've got a problem that perhaps someone can help me with. I've noticed some green bacteria growing in the water and have discontinued it's use for now. How do I keep the water fresh?

Cover the barrel with something that excludes light pretty completely. The photosynthesising micro-organisms in your barrel then quit.

1. Clean your barrel out. Assuming it is made of type 2 plastic, HDPE, you can use hydrogen peroxide, boiling water or bleach (if you like using toxic chemicals). If you use boiling water, use 1 gallon at a time and swirl the water around inside the tank. Do not screw the caps back on while the hot water is in the tank because the pressure from the steam will rupture the tank. Pour the water out and repeat at least one more time.

2. Make sure you have a debris filter on the inlet. Any organic matter that gets into the tank becomes a food source for microbes.

3. Do not collect the water when it first starts to rain because it is filled with microbes or nutrients. Allow it to rain at least .2 inches during a single storm to clean off the roof before collecting the water. If it has not rained for a month or more, you will have to allow it to rain longer to clean off the roof. Experiment to determine the amount what works at your location and with your type of roof. My data assumes a galvanized steel roof in a forest. It is hard to exclude the green algae/bacteria when collecting snow melt. While the snow sits on the roof for several days or weeks before melting, it gets dirty. High rain rates, such as a thunderstorm dumping 1 inch of rain in 10 minutes, yields the cleanest rainwater.

In the West, legality of this type of project varies widely. Here in Colorado, rainwater harvesting -- diversion of runoff into storage -- will generally be illegal, as the rights to the natural runoff from your property are almost certainly owned by someone downstream. On a small scale like a rain barrel no one is likely to care; but a 1200-gallon cistern is more likely to attract the attention of the authorities. Even graywater recycling can be problematic since water rights are for single use only. But the single-use law applies only to water in its "basin of origin". Denver Water moves considerable water from the other side of the Continental Divide, and that water can be used multiple times. They have to account for it carefully, and show that, for example, the graywater used in irrigating the city parks never exceeds the amount of water they're diverting from the other basin(s).

(edit: responded to a different comment here initially)

I think this is a prime area for political activism. In Arizona, greywater has been legalized by statute, and it's my understanding that rainwater harvesting has as well. Colorado (or any other state) could do the same, just as Colorado has with their recent solar access law (where HOAs now can't disallow the installation of solar panels).

As for the legality of rainwater collection under Colorado's prior appropriation system, I don't think that a system for home use will cause problems. There are not authorities that are out seeking to enforce the current rights system--instead, the downstream water owner would have to identify that you're reducing their flow and then bring an action in water court to get you to stop. While this may sound like a possibility, a specific downstream user will need to establish a specific causal link between the rainwater collection activity and a specific failure of a watershed to meet their allotment--while correlation is pretty easy to prove, I find it hard to believe that any attempt to enforce this would fail because demonstrating the legal causation seems almost impossible. Small residential systems are probably going to fly under the radar--for example, virtually any landscaping violates some downstream user's water rights because it causes more water to absorb into the local water table rather than runoff into the watershed. Someone who tears out a 1 acre parking lot and puts in 1 acre of grass will cause a much larger change in downstream water rights than a homeowner with a 10,000 gallon, roof-fed cistern. Based on the limited research I've done on this previously, no action has ever been brought in Colorado for this type of use. The only time I've ever heard of it becoming an issue (in Colorado) was with an effort to install a very large living roof in Denver. That said, it seems to be a largely untested area of law...

Example story about Colorado's catchment laws here. As you say, it is unlikely that the authorities are going to go after someone doing things on a small household scale. OTOH, it seems entirely possible that, should you come in contact with the local authorities on other matters (eg, a building permit or various business inspections), the presence of the illegal diversion system may be more problematic.

I believe this statement of yours, "...instead, the downstream water owner would have to identify that you're reducing their flow and then bring an action in water court to get you to stop..." is incorrect in Colorado; the relevant courts have established the doctrine that all precipitation is presumed to flow into a stream, and as the streams are already over-appropriated, a new diversion is immediately illegal. IANAL, but if a complaint about an illegal diversion were filed, I believe the authorities would be required to investigate and if appropriate, press charges.

The power companies need to build additional baseload generating capacity here, and obtaining the rights to water for cooling purposes has been difficult: under the Colorado Constitution, all domestic and agricultural claims are senior to any manufacturing claim. Shell is buying up water rights in NW Colorado in case their oil shale scheme turns out to be practical. They're having to buy a lot of rights, since they will be using the water for non-agricultural purposes.

The presumption pointed to in the article you linked (presuming that all precipitation is presumed to flow into a stream) looks like it will be quite a problem. I'd love to say that Colorado legislature, recognizing the value of rainwater harvesting for the state, would carve out a statutory exception for small-scale residential harvesting. My guess is that isn't very likely to happen--as you point out, too many monied interests on the other side. It's also worth noting that, aside from the potential for massive future shale oil water requirements (I think EROEI issues will keep shale oil from any significant development), coal bed methane--something currently very big in Colorado, Utah, etc., is also very water intensive...

Maybe the way to fight this is to buy some small downstream water right, and then start reporting to the authorities, or bringing suit against every person who puts a bag of mulch on their yard. It seems that such a tactic (while there are many other problems with it) might serve to point out the stupidity of outlawing residential rainwater harvesting, and may force the Colorado Supreme Court to distinguish between small, residential harvesting and large-scale or commercial rainwater harvesting?

The thing is that vegetation does not take up moisture*, it just borrows it for a bit.

[*To be precise, it does take up some of the moisture, combining the H2O with CO2 to make cellulose - wood. But this is not a vast amount, representing perhaps half an inch of rainfall equivalent annually.]

On the one hand we have the Colorado state legislature claiming that if rainwater is harvested for vegetation, it will be unavailable for streams. On the other hand, we have someone in this very comments thread talking about transpiration - plants releasing moisture into the air. Where does it go once in the air? Well, it does not disassociate into hydrogen and oxygen, it does not stop being water. Instead it precipitates - rain.

So we capture rain for vegetation, the vegetation takes the moisture for a bit, releases it into the air, it forms clouds and then returns to the Earth. And it all reaches the stream eventually.

This is why in fact we find that in areas which are heavily deforested, rainfall drops [source] Cut down all your trees, and it stops raining; plant a lot and it starts.

So I think perhaps these various legislatures are not really aware of natural processes. But in this they're not unique. Here Down Under we've had for years farmers looking at stands of trees, and thinking they'd absorb the water which could go to crops they cut them down... and then being surprised when local rainfall dropped.

It all reaches a stream eventually, but not necessarily the same stream. That's the crux of the legal issue, because water rights are tied to flow in specific streams and rivers. In Colorado, at least, it's quite likely that water lost from transpiration will not return to the same stream due to our prevailing wind patterns and high relief that produces many distinct drainage basins, including the continental divide that runs right through the state.

After 18 years of harvesting water in Colorado, the water right may be taken by adverse possession.

I have read the following expression:

"In Colorado, we talk over whiskey, but we fight over water."

Only a Denver lawyer would say it that way.

Everyone else says "Whiskey's for drinkin', and water's for fightin' over!"

I think we might have to start planning for +/- 70% seasonal rainfall variation. In Australia every big city is installing desalination plant with water costing $1-2 per 1000 litres. That's almost too expensive to brush your teeth let alone water the garden.

I think every house on a quarter acre block could justify a 50 KL/ 12000 gall rainwater tank with electric pumping. Get rid of some junk to make room for it. Also run some guttering from a detached shed or garage. If needed you can have automatic top up by piped water. Whether that tank is also big enough as a heat pump ground source I'm not sure. You should be able to keep vegies going all year on a trickle system. Shade trees should be native to the area and not need much extra. With hidden 1" polythene pipe and gate valves I've rigged up a quick coupling to a small two stroke firefighting pump kept in the garage - better than waiting for the fire brigade.

Those on a hilly block could consider terraced garden beds like steps. Water from the higher beds seeps to the lower beds. Leave space to walk between the levels.

Your point about needing to prepare for periodic drought is important, I think. Any system, when it's operating exactly at its limits, will fail in the face of even minor deviation. If you plan on collecting exactly the amount of water you absolutely need based on annual rainfall, you're dooming yourself to failure. However, if you have plenty of slack in the system you can overcome historic periods of drought. While this slack/failure issue is fairly universal, with issues like water in the Western US, a region known for high variation in rainfall, it can be critical. This was exactly the problem that led to the downfall of the Chacoan civilization--the drought that killed off the Chaco complex wasn't actually that severe, but because Chaco had expanded to require an average rainfall pattern, when that didn't happen the whole house of cards fell apart...

I have 450 gallons in capacity, three barrels and a 280 gallon "IBC tote" which is a polyethylene cube on a pallet in a metal cage. These can be purchased second hand for about $125.

I cut my downspouts and replaced the bottom of the downspout with 3" pvc. At the height of the barrel the pvc pipe is topped by a 3x1.5" reducing tee, which sends the water to the barrel through a 1.5" pipe. These never clog. The diverter is a "test cap," a thin plastic plug at the bottom of the tee atop the pvc downspout pipe. I have drilled out the center of the test cap and use a large rubber shower stopper as the diverter plug.

I have also mounted 3/4 hp "shallow well pump" from Harbor Freight (China) on the IBC, and use it to fill an open 40 gal drum for filling watering cans, and I hook the pump to a hose for watering the landscape. I have not been using the industrial ball valve at the base except to flush it sometimes.

Bases for the barrels are unmortared masonary blocks, and the 16" square pavers look pretty good. The same blocks were used under the IBC.

For the screen topped barrels, I have put a kitchen strainer on top with a rock in it to catch leaves and such as it comes from the downspout. It helps keep the main screes clean, and it cost $1. I have removed screens on the overflow as no bugs seem intersted in going up even a short pipe to get in.

I have lived in Micronesia several times, and rainwater off the roof was our principal source of drinking water.
Split bamboo off the edge of the tin, draining into a 55 gallon drum. No electricity, plumbing, etc.
Cooking and lighting with kerosene (except for the human skull candle holders, from Japanese Soldiers from WWII).
Speared fish for trade. Not bad for as boy off the streets in LA---
That was a land far far away, in a time long long ago---

(except for the human skull candle holders, from Japanese Soldiers from WWII).

Still got those holders?

No, the skulls got left behind---
I island hopped (Truk, Ponope, Majuro, Kwajalein, Johnson, Oahu)-
and ran out of cash upon getting to Hawaii. Sold the Nikonos Underwater camera after some Honolulu adventures and got back to LA.

Looking for decorating ideas for your tiki bar?

A friend of mine (Max Meyers) is a local permaculture teacher and designer and I've had him go after my yard for a couple of years. Much of what Brad describes has been done at my home too, and I can attest that it works wonderfully.

For water catchment off the roof, I installed a 2000 gallon bladder tank under my house. This is nice because it doesn't take up space outside where trees and garden space is often precious.

I am planning Water-catchment because I am at the end of a 10 kilometer 4 inch water supply pipe.

The problem is not water availability, we have monsoon rains every day. The problem is distribution. Also, we then have four months with not a drop of rain.

I think water catchment in dry areas is not sustainable without massive supplements from outside and(Oil) inputs.

The dry areas before they became suburbs were what nature intended them to be. All additional water activity in these suburbs is based on a false premise.

The circulating water into rain clouds within every 100.000 sq kilometer area is pretty constant. Its a closed loop. Once this water starts sitting in a million tanks, it is not immediately available for making clouds.

The heavy foliage being planted within tank proximity, where before it was not self sustaining, is not self sustaining. Peter is being robbed to pay Paul.

I would concede that if one could initially import some few billion gallons of water, and start millions of square meters of foliage transpiring sufficient water vapour, it may change the climate of the region, and it may become self-sustaining.

Every square meter of foliage transpires over a litre of expensive stored water a day. (ball-park)

In the short term suburban catchment can do very well. In my opinion, in the Post-oil times the areas will revert to what they were before colonization.

Dubai will be the disaster of the millennium.

You are probably right about most large desert settlements being doomed, but the Seawater Greenhouses do look like a potential solution to some of the water deficit.

Something I've heard from the folks living around the Columbia Gorge forests:

The State of Washington's water use laws are so strict that you can't even use the run-off from your roof without a permit from the State government.

Pretty striking if true because Washington State has some of the most intense rainfall in the US.

from an appendix of an upcoming article:

France – A Comprehensive Non-Oil Transportation System

• High Speed Inter-City Rail
• Inter-City Freight Rail
• Urban Rail
• Bicycles
• Walkable Neighborhoods

President Chirac made it a national goal to electrify “every meter” of the French National railroads (SNCF) and “burn not one drop of oil”. This goal was set on January 1st, 2006 with a twenty year deadline.

France has been building their famous TGV lines for over 30 years, one line at a time. Now that the original Paris-centric system is 100 km from completion, a new network of additions, bypassing Paris, have been announced and, for the first time, three different TGV lines are simultaneously under construction.

France has had an aggressive tram (Light Rail) building program for over fifteen years, with only five French towns of population 100,000 or more without a tram or plans for one. Recently, France has stepped up the pace with plans for 1,500 km of new tram lines (22 billion euros) in the next decade.

And velibs. Rental bicycles scattered all over in almost a dozen French cities, typically with the first half hour free. Many more bicycle paths and lanes have been built in recent years. The stated government objective is to ensure that 10% of in-town journeys are made by bike by 2010, but the results are trailing plans with only 3% in 2007. However, Portland Oregon and Davis California are the only US cities that exceed 3% AFAIK.

Mulhouse France (population 110,900, metro 271,000) illustrates just how comprehensive the French program can be in a best case. This remote town where France, Germany and Switzerland meet, got it’s first tram (Light Rail) line in 2006. By 2012, they will have 58 km (34 miles) of new tram lines (they would also have had a tram line to Basel Switzerland if Franco-Swiss co-operation had been better).

In 2011, Mulhouse will be the temporary terminus of a new TGV line and 200 velibs (rental bicycles with the first half hour free) have recently been installed.

The end result is that by 2012 a resident of Mulhouse can walk out their door, grab a velib rental bicycle, drop it off at the tram station or just walk, take the tram to the TGV station and be in Paris in 4 or so hours, and anywhere in France in a long day, all with a drop or two of lubricating oil and minimal carbon footprint.

In the non-transportation area, France is installing large numbers of solar hot water heaters and geothermal heat pumps.

With significant difficulty and economic loss, France could adapt to a prolonged loss of a fraction of their imported oil.
---------

What more would you have them do ?

Alan

Alan, even bikes and electric bikes and trikes, not to mention electric delivery vehicles, need roads to get goods to the doorstep.
Memmel was arguing that the choice will be between maintaining roads and railways, with the priority having to go to railway.

I would go along with that, but you still need to move goods from the railhead to the door.
EV's are not going to be anywhere near as common as private cars are now, but some transport will be needed.
Concrete could be substituted for asphalt, and many minor roads reduced to gravel etc, but maintenance especially for bridges would still need doing.

What is your take on maintaining the needed capacity? Of course, the issue is a lot easier in France, as there are less severe frosts and very high temperatures, not to mention that the large amount of nuclear power make the issue one of liquid fuels rather than energy as such.

Thoughts for France and the US?

If there are less cars, there can be less roads. I mean, if fuel is $20/lt then we are not going to need four lane highways.

Interesting comment about France transport. There are problems though. The SCNF (national rail system) is systematically eliminating stops at smaller towns along established routes. Gourdon is the third largest city in the Department of Lot with 4,882 population. Yet it is becoming more and more difficult to take a train to Paris which is north on the line going through Gourdon. There seems to be a high interest on the very visible (and extremely expensive) high speed lines that connect major cities at the expense of smaller towns. Thus comes at a time when auto transport is becoming increasingly unfordable. thus smaller urban areas are becoming more and more isolated. Towns through out France are protesting this trend but so far without any effect.

Sorry, posted on wrong article. Clicked the wrong window when copying & pasting.

Alan