I just finished chopping nine-foot weeds on our back acre. (In case you're just tuning in, this is chapter three in our continuing adventure in creating a sustainable farm in Bosque Farms, New Mexico). What was supposed to be an aesthetic combination of yellow sweet clover and grass mix to feed and cover our soil in preparation for planting next year turned out to be a weed party hosted by the Amaranth family. In my continued farm ad-libbing, I now tell the neighbors that our soil replenishment strategy is a designed “controlled chaos” to maximize nutrients and aerate the soil. Before they can sift through that pile of words, I change the subject to the weather.

When we lived in San Francisco, the topic of weather was primarily used to fill gaps in conversation. We would discuss the weather in preparing for a commute, or in choosing an outfit to match the umbrella, or we would humor visitors by citing Mark Twain’s famous quip, "the coldest winter I ever spent was a summer in San Francisco." Here in New Mexico, if you bring up the weather as a subject you better be prepared to talk about the weather.

In our area of New Mexico, we experience all four clearly defined seasons. During the summer months, the main subject is rain. How much will we get this month? Does that approaching thunderhead have potential? How does it only rain on my neighbor’s property and not mine? It’s possible to have full conversations about every conceivable weather website and how to systematically choose features from each site to form an accurate assessment of weather conditions. One website offers the best storm tracking capabilities. Another site provides the most detailed data during and after a weather event. Yet another site provides historical data beyond the current month. A friend of ours in Santa Fe even built his home around an antique weather station, demonstrating that the best data often comes from your own backyard. 

I spend more time now than ever on the weather web sites, obsessively hitting the refresh button, and validating weather patterns through the window. Why, you might ask?

To be prepared to catch the rain.

In the previous article, I mentioned that we have three agricultural water sources on our property: irrigation from the Rio Grande, an underground well sourced by an aquifer, and rain. (The Village of Bosque Farms provides water and sewer for our home use.) I also shared the emotional practice of flooding our back field from an irrigation ditch, and we continue to provide drinks for the weed party with this practice. But there are many issues involved in using the irrigation system as a foundation to a sustainable farm. Some farmers doubt the quality of the water despite reports showing that the water meets EPA standards. But we also wonder if irrigating from Rio Grande River water is a clean and acceptable practice for growing organic products in the future.

Climate change predictions for our regional weather patterns also show a threat to the irrigation process. We may be on a path to earlier and lower snow melt run-off that would limit the amount of water for agricultural use and drastically reduce supply during the critical irrigation demands of late summer. To us, being sustainable is having the resources to make our own decisions and to allow us to adapt to prevailing forces—all while maintaining homeostasis on our land. Solely relying on the irrigation system to build our farm does not seem like a course to sustainability.

The well water is yet another tricky situation when it comes to sustainable supply. Currently in our area, the majority of property owners have unlimited, unmonitored use of well water. The “beg for forgiveness” strategy for well water use works best, since asking for permission beforehand comes with monitoring. For example, one local farmer is required to provide usage reports to Bosque Farms water management because he asked permission to establish a well. Another town resident runs sprinklers from his existing well with reckless abandon for hours on a half-acre of lawn grass in the middle of a hot summer day. The current mismanagement of the aquifer could bring about monitored well water use in the future and further limit agricultural use in the midst of continued development.

While we were naïve about many aspects of our move from urban to rural living, we did anticipate the challenge of figuring out the appropriate and intelligent use of our precious water resources. (Score one for the hipsters!) In this anticipation, we knew that our third water source—rain—was going to play the biggest part in developing our farm. Unlike some areas of the U.S., New Mexico currently has no restrictions on capturing rainwater. In fact, Albuquerque encourages rainwater harvesting through education and an equipment rebate program.

Now all we need is for Mother Nature to cooperate.

A funny thing happened in May as Albuquerque hosted the ICLEI Local Action Summit , supporting local governments for sustainability: it rained. In the middle of a very dry spring, it rained hard enough to accrue our average May rainfall in just two days. It’s ironic that a conference covering the maintenance of our unpredictable supply of natural resources under the pressure of increasing populations was treated to an unusual deluge in a semi-arid area such as Albuquerque. While attending the conference, I had to point out this irony to a speaker from the Albuquerque water authority.

At least Mother Nature and I had a good laugh at the paradox.

And She continues to laugh through the end of July as our current precipitation total is sitting approximately two inches above the monthly average (3.39 in. vs. 1.27 in.). This total is a conservative number compared to what we have measured on our property. Relying on weather accuracy in New Mexico from a data station that sits 15 miles away from our farm is akin to flying to London on a trip to Paris. There is a gap.

Those 3.39 inches of rain can actually translate into 11,000 gallons of captured water. No, we are not magicians, rather the lucky inheritors of approximately 5260 square feet of roof surface on our home and out buildings. This is why we are so excited about using rainwater as our foundation for a sustainable farm.

There are several formulas to calculate rainwater catchment potential from roof surface area. The Texas Manual of Rainwater Harvesting formula asserts that you can capture 0.62 gallons per square foot surface per inch of rain (square feet x inches of rain x 0.62). Another formula shows that you can capture 600 gallons of water per inch of rain per 1000 square feet of catchment formula (square feet x inches of rain x 600 / 1000). My favorite calculation comes from Brad Lancaster in his book Rainwater Harvesting for Drylands and Beyond, where you multiply your roof surface area (square feet) by the rainfall (measured in feet by dividing your inches of rain by 12) and 7.48 (representing gallons per cubic foot). I think his formula (square feet x feet of rain x 7.48) is my favorite because it yields the highest total of captured water. I'm an optimist.

Using these formulas, we have calculated that we can passively capture between 519,000-539,000 gallons on our entire two-acre property with an average annual precipitation of 9.93 inches. If we took advantage of the total 5260 square feet of roof surface around our property, we could potentially store and use between 28,000-32,000 gallons of water, given  9.93 inches of annual rainfall (minus first flush waste if we discard the first 10-20 gallons of each rain event). The volume of free water we could harvest from rain storms is almost unimaginable. So we did what any doubtful, yet hopeful, couple would do in the face of such confusing numbers: We just started to catch rain.

At the beginning of our rainy season in late June, we organized a makeshift water catchment system consisting of several five- to 15-gallon buckets placed in downspout areas around the house. During any given rain storm, we collected about 60 to 75 gallons of water. In less than a week, all buckets were full with no additional storage capacity. Every drop of rain beyond our capacity was a painful reminder that we needed to upgrade our system.

Enter a company called Soilutions and their water catchment expert, William “Bard” Edrington. Bard marveled at our water catchment possibilities once he visited our property. After sharing our situation, our trial-by-error approach to building the farm (a.k.a. blind experimentation), and listening to Bard detail our options, we settled on a 1,650-gallon above-ground tank. In one of those “your lifestyle really has changed” moments, we sold stock in a promising pharmaceutical company in order to purchase the tank. Any regret that we have in selling that stock is replaced by pure joy when we pour five-gallon buckets of fresh rain water into that beauty of a tank. If we are to fulfill the potential of our rain catchment opportunity, I have a feeling what little remains of our old company stock will give way to tanks.

Capturing rainwater in New Mexico is similar to constipation: it’s a waiting game, but you had better be prepared when it surges. We had one of those episodes not long after we installed the tank, where we were more than an inch of rain poured down on us in a little less than an hour. In total, we captured nearly 300 gallons of water in that one hour, a fraction of the 1,500 gallons we could have harvested with a gutter system in place to route the water to the tank.

It has been three weeks since the tank arrived. We are only capturing water from the roof of our house (the same makeshift placement of buckets in downspout areas), yet we have stored and used more than 800 gallons of water in those three weeks. The next step in our water catchment plan (stay tuned for our next episode, “How the heck are we going to pay for all of this?”) is to install gutters around the roof to catch the water more efficiently.

The rain water we’ve captured has nourished eight tomato plants, six sweet pepper plants, eight rows of various vegetables, two large planters of flowers and herbs, a mix of seven or eight ornamental, culinary, and fragrant plants, and four newly planted New Mexico redwood trees (or taxodium mucronatum neomexicanca for the arborists out there).

Our sustainability dream is to nourish the farm on rainwater alone. The reality though, in a place that experiences occasional drought, is to use two or all three sources of water to feed our plants. This trifecta of water sources should be adequate to build our foundation of sustainability. So, how are we going to build a working, sustainable water supply system for our property? Until we reach that epiphany, we have a rudimentary idea and will share details and costs of the plan with you next time. For now, we have a weed party to attend. Take care, and be mindful of the rain.

Jonathan and Valerie would like to receive reader comments and suggestions.  Feel free to email them at greenhornfarmer@yahoo.com.

Related articles:

Flooding the Farm
Hipsters Turn to Harvesting

Photos by Valerie Ashe