Rain Harvesting & Ollas: Practices in Water Conservation & Irrigation

By Mary Karish

Contributing Writer

Dripping Springs, a town nestled in the Texas Hill Country, is home to juniper trees, serene rolling hills and rocky creeks. John Moss, an early settler who arrived in the area in 1854, needed a name for his town in order to establish a post office. His wife suggested Dripping Springs, a tribute to the many springs that adorned the area. Today, 1,100 inhabitants live in this town, dubbed “the Gateway to the Hill Country.” However, not all residents have access to springs, creeks or city water. Lori Haynes and her family, who built a house on a 10-acre plot of land, are some of those people.

Lori, a native of Fort Worth, grew up watching her mother tend the family garden. “I took it for granted that anyone can start a garden anywhere,” she said. “I was wrong.”

The land her family bought in Dripping Springs did not have access to municipal water. The water quality of the surrounding underground wells was poor and not suitable for consumption or irrigation because of its high salt content. Many of the springs had dried up because of over-consumption. The only logical option was to transport water and store it in a tank. This enterprise proved to be expensive, and water quality could not be independently verified. Instead, Lori and her family turned their eyes to the sky, calling on “cloud juicing” — or rainwater harvesting — and using “ollas” to irrigate the vegetable garden.

Every type of water, whether it comes from a well, a river or a pond, was once a cloud. When rain falls, it permeates the soil and the rocks. Rainwater not only collects minerals as it infiltrates the earth, it gathers agricultural runoff, industrial releases, firefighting foam, pharmaceutical drugs and even the chemicals used during water treatment. If rainwater is captured before it hits the ground, it is free of these pollutants.

Storing rainwater has many crucial advantages. It could be a crop-saving measure for farmers when aquifers run dry as a result of a chronic drought, similar to the one that plagued most of Texas in 2011 and 2012. It can relieve gardeners when municipalities impose water restrictions on residents and outdoor water use is limited or prohibited. For the Haynes family, it made it possible for them to build their home without access to municipal water.

Rainwater harvesting does not require a complex system to ensure a quality water supply across several miles. It conserves energy and reduces the possibility of leaks and contamination. And it saves money. When municipalities lay water systems, replacement and maintenance of corroded pipes become an expensive endeavor.

The Haynes family built a 20,000-gallon water cistern. When it rains, their home roof acts as a water collection surface. The home’s gutters capture the rain, which is directed through underground pipes to a cistern situated about 100 feet away from the house. The water inlet leading to the tank is below the lowest gutter in the house, allowing gravity to work its magic. As rainwater rises in the vertical pipes, it spills into the tank. To utilize the stored water, the outflow pipe goes through a water pump to ensure an even flow of water into the house. The cistern also comes with an overflow port that allows excess water to be diverted to another tank, a rain garden or a pond.

According to Texas A&M Agri­Life Extension Rain Harvesting website, a 3,000-square foot roof has the capacity of providing 9,500 gallons of rainwater with a five-inch rainfall in a given month. A typical Texan household consumes about 7,000 gallons per month for indoor use.

Metal roofs, asphalt shingles or paint may leach into the rainwater being collected. To ensure healthy potable water, a water purification system, such as reverse osmosis or UV light system, must be added. The initial investment of a complete water collection system may be comparable to digging a water well. However, the quality of underground water is greatly affected by modern-day pollutants, and the availability of underground water may be compromised by chronic droughts. In addition, the upkeep costs of water wells far exceed that of the nearly maintenance-free rain collection systems.

According to Billy Kniffen, past vice president of the American Rainwater Catchment Systems Association (ARCSA), irrigating an acre of turf grass with one inch of water requires 27,000 gallons. “Homeowners with rainwater collection systems tend to appreciate the value of water and learn to use it wisely.”

Rainwater collection does not stop with human consumption. The Haynes family also built a water catchment system to serve their backyard chickens. The rain that hits the roof of the coop is collected for the chickens’ drinking pleasure.

Although Texas was blessed with adequate rainfall in 2015, another drought is not a matter of if, but when.

“An adequate water supply is a two-component issue: the amount of rain we get and the amount of water we use,” said Steven Sweeney, president of Rain Harvesting Supplies, Inc., a Texas-based online retailer of water tanks and components, and a professional instructor for American Rainwater Catchment System Association. “Simply getting a lot of rain in one year doesn’t solve the problem, and it doesn’t change how much water we use. We had an outrageously wet year last year and the lakes in Texas were fuller than they’ve been in my lifetime. But I estimate in two to five years we’ll be back to the water-crisis point unless we get ridiculous amounts of rain. We can’t count on seasonal variations as a reliable water source.”

Recent projections for Texas indicate that the 2014 population of 27 million could more than double by 2050, and all of those residents will be demanding clean water. “Rain harvesting is how we’ll get some of the water we’ll need,” Sweeney said.

Rather than reacting to a water crisis after it occurs, it is better to collect rain, conserve water and plan ahead to ensure adequate supplies. Several Texas cities offer tax rebates for homeowners who harvest rain. In Austin, the city’s rainwater harvesting rebate program offers homeowners 50 cents for each gallon of non-pressurized storage and $1 for each gallon of a pressurized system up to $5,000. By law, homeowners associations in Texas cannot ban the installation of water catchment systems. It is not far-fetched that rainwater harvesting for landscapes may one day be required when constructing new residential developments.

Efficient use of rainwater does not stop with collection systems. Lori recognized that irrigating her vegetable garden required a novel approach as opposed to the conventional irrigation system. After exhaustive research, she came across the olla, a Spanish word for a clay jar used for irrigation in arid Central America. The olla originated in Asia more than 4,000 years ago. In Sri Lanka, a country in Southeast Asia, the system is still used in the interior where it is referred to as kalagediya, a Sinhalese name for unglazed clay pots.

Ollas are buried in the ground close to the planting area. The top of the olla is exposed above the surface ground, where it can be easily filled with water for sub-irrigation. When the soil starts to dry out, water seeps out of the pot until the soil is moist again, but without the risk of runoff or evaporation. The water seepage is regulated by the soil’s moisture tension, and when the soil receives adequate water, the seepage stops. As plant roots grow, they continue to pull water from the olla according to their needs. This clever irrigation system operates without the use of electricity.

Ollas not only irrigate plants but they create a weed-free environment. Because irrigation takes place below the ground, the topsoil dries out, which reduces soil compaction and the need to weed. Liquid fertilizer added to the pot provides consistent feeding.

To use an olla, simply bury it in the ground, leaving the neck of the pot exposed. Fill it with water, and place plants within five inches of the pot. The water will gradually seep through the clay, irrigating the roots. If planting seeds, water them initially until they germinate. Once they establish a root system, let the olla do its work.

Ollas should be made of unglazed clay, which is porous and allows water to seep out. Two sizes of pots are available to serve specific planting areas. A two-gallon olla will irrigate plants for three to five days in the absence of rain. A one-quart olla is suitable for containers and can irrigate for up to a week.

A 4-by-4 square foot garden will require a two-gallon olla buried in the center to ensure uniform watering. Replenishment depends on the type of plant and its needs. For example, watermelons require constant moisture, so the olla must be refilled every three days. To avoid mosquitos making a home in the pot, cover it with a rock, tile or lid. When using more than one olla, ideal spacing would be three feet apart measured from the center of the pot’s neck in order to avoid overlapping the irrigated areas.

Cloud juicing and olla irrigation complement one another. Cloud juicing is the simplest way to harvest rain that would have otherwise run off cement pavement into a sewage system. Harvesting that rain not only conserves water, it also encourages appreciation of this important natural resource. People who harvest rainwater are less likely to waste it because they have a better understanding of how limited it is.

Olla irrigation reduces water requirements because of the reduced rate of evaporation and increased permeability of unglazed pots. Olla pots have proved to be self-regulating, allowing gardeners who cannot water frequently to irrigate their plants at a constant rate. They also help gardeners who are limited by local ordinances on outdoor watering to preserve their plants.





Make Your Own Ollas


Storage Tanks


Subscribe today!!