This is the story about how a trade association, the Oregon Association of Nurseries (OAN), anticipated restrictive legislation; developed its own, voluntary solutions to a problem; and was able to eliminate the need for additional state regulation. It’s also a story of how a simple and relatively inexpensive procedure from a San Luis Obispo, CA-based company, EP Aeration Inc., helped members of that association succeed in their efforts.
The problem was the need to protect the state’s vital watersheds. By the late 1980s, environmentalists and agriculturalists from across the nation were concerned that runoff from some farming operations could be causing pollution of streams, lakes, and rivers. That concern had been written about extensively in the Midwest by the late 1970s. The OAN decided to develop and adopt a voluntary program among its more than 1,800 members to recapture and reuse irrigation water to prevent runoff and any environmental consequences.
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| This pond has yet to be treated. Algae and other materials can easily clog pumps and irrigation systems. |
According to Don Richards, a member of the OAN’s natural resources committee, the association learned that the Oregon State Legislature was planning a bill to deal with water runoff. At the same time, the Clean Water Services Bureau in Washington County had begun taxing runoff from hard surfaces.
“That tax wasn’t aimed at nurseries,” Richards said. “but nurseries with container growing operations usually have large graveled areas which would fall under the ‘impervious surfaces’ guidelines for imposing the tax.”
His own business, Applied Horticultural Consulting, which works with landscape operations, has put him in contact with many of the OAN’s other members over the years. He recalls that Paul Fukasawa, who was president of the OAN at the time, Greg Pilcher of Iseli Nursery, and Tom Fessler of Woodburn Nursery were among those spearheading the effort to develop a best management practices program within the association’s membership.
That effort, in combination with consultations with Oregon’s state agricultural agency, produced a voluntary program that obviated the need for specific legislation on release of irrigation water into the watershed. The recapture and treatment program began in earnest in the early 1990s.
“The nursery industry is, by its nature, sensitive to environmental concerns,” Richards notes. “The recapture agreement with the state benefited all of us by heading off legislation, sure, and it helps our public image too. But it’s important to note that all of us live and work in the natural environment; it’s not something far removed from our daily lives.”
He further says that the nurseries implementing the best management practices have benefited from a number of improved efficiencies and reduced costs. Not the least of those is the conservation of water, vital to any agricultural operation.
Recapturing and recycling the water was problematic. Whether fertilizers, pesticides, or even the hydrocarbons from ATVs were in the runoff, recapture meant that the biochemical oxygen demand (BOD) of the water would increase exponentially.
Algae blooms were more than an eyesore and offense to the nose, because the material could clog pump mechanisms or drip systems.
Algae could be controlled somewhat by utilizing chemical treatments such as copper sulfate. However, that was like using Clearasil on pimples: The underlying causes of algae blooms, odors, and other negative conditions were not being addressed. The symptom was being treated, not the disease. In addition, chemical control of algae can result in significant buildup of those chemicals in the sludge; this can create a potential hazardous-material disposal problem if the lake or pond is dredged, for example.
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| A large lake at Leo Gentry Nursery in the Willamette watershed has been using EP Aeration equipment for six years. |
There are two principal problems facing any sequestered body of water: thermal stratification and low levels of dissolved oxygen (DO).
Thermal stratification can occur with as little as a 3-degree (Centigrade) difference in temperature between the surface of the water and the benthic layer just above the bottom. A cold layer known as a thermocline forms, restricting any natural circulation of the water below it. All the living things, as well as the metals and chemicals that consume oxygen, continue to do so until most life is snuffed out and precipitates to the bottom, along with the chemical nutrients.
Low DO levels allow the nutrients usually trapped in the bottom sludge to release into the water column (called an anoxic release), causing a principal symptom of low oxygen levels to appear: filamentous algae.
There are additional symptoms that can be detected. Fish kills or fish seeming to gasp for air at the surface of the water are examples. Sulfurous odors (from hydrogen sulfide gas) are another.
There is a solution: Prevent thermal stratification and raise the DO levels throughout the water column. EP Aeration met with members of the OAN in the early 1990s to discuss use of its aeration systems, which usually operate on 120 VAC (household electrical current), to mitigate the problems. The low electrical cost of operation has been a significant appeal of EP Aeration’s equipment over the years, along with ease of installation and maintenance.
Jim Chatelain, of the family owned-and-operated Chatelain’s Nursery near Boring, OR, was the first OAN member to install the company’s systems. He used it on one of his recapture lakes in September 1992. Up to that point in the year, Chatelain had spent some $13,000 on copper sulfate to knock down the algae. Legend has it that he still has the same 50-pound bag that he had in the fall of that year because the effectiveness of the aeration system has virtually eliminated the need for it.
Neither party anticipated one interesting consequence of installing that first EP Aeration system. Water tests and Chatelain’s observations showed that the sodium absorption rate (SAR) was affected, so that sodium didn’t collect in the root zone but instead passed through. That’s important because recaptured and recycled water tends to attain a higher content of sodium and similar substances.
The goal of aeration, according to Mike McGee, president and general manager of EP Aeration, who installed the first system at Chatelain’s Nursery, is sufficient oxygenation to meet the BOD of the water body. A number of aeration methods exist, but he selected bottom-laid, fine-bubble delivery through proprietary tubing because of its efficiency and low cost of operation.
“Essentially, we’re blowing air into the tubing at the bottom of the pond and letting simple physics take over,” McGee says. “The tendency of an air bubble in water is always to rise to the surface—no additional energy is required.
“The trick is to control the size and rate of rise of the bubble through the water column without disturbing the sludge. That’s best accomplished by using a diffuser, which creates a laminar flow of bubbles.”
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| A 19-million-gallon recapture lake covers 4.07 acres at Iseli Nursery. |
The size of the bubble and how fast it rises are the factors that determine how much water can be transported to the surface. Years of testing and use in the field demonstrate that the tubing utilized by E.P. Aeration produces precisely the laminar flow, bubble size (approximately 1⁄4 inch), and rate of rise (in this case, 0.8 feet per second) required to move the maximum amount of water from the bottom to the surface. Two hundred and fifty feet of the specialized tubing can circulate more than 20 million gallons per day.
“Despite the fact that this diffusion system has the highest oxygen transfer rate in the industry, the real oxygenation of any body of water takes place at the surface through wind and wave action,” McGee says. “The objective isn’t really injection of air, but movement of the water.”
It seems to have been effective for the company’s customers since that simple beginning. Chatelain’s was begun as a berry farm by the family patriarch and converted to a nursery in the mid-1970s. It’s now operated in the field by Jim and his brother, David, and in the office by his sister, Judy. The busy operation has installed E.P. Aeration equipment on the other two lakes on the property, and it maintains the equipment assiduously. Prize koi are kept in two of the lakes, attesting to the effectiveness of the systems in maintaining an ecological balance in the water features.
Other OAN members have followed suit in installing the company’s equipment over the past 14 years, including nearby Iseli Nursery, which has a 19-million-gallon recapture lake covering 4.07 acres on a large and busy property. Ron Boltman’s multigenerational operation consists of 25 acres of rhododendrons, and his two ponds are 700,000 gallons and 3.03 million gallons respectively. Kramer’s Nursery of Corvallis also grows rhododendrons and has two lakes of more than 4 million gallons using the equipment.
Fisher Farms, Thompson and Walters Nursery, Woodburn Nursery and Azaleas, Don Marjama Nursery, and others around the state are also using the company’s Laminar Flow Technology systems. Incorporated in 1991, EP Aeration has hundreds of equipment installations throughout North America and the Pacific Rim, at major golf courses and resorts, in planned communities and housing developments, and in other agricultural applications.
As for the OAN, it continues to strive for high environmental quality among its member operations, to provide information resources, and to operate one of the largest grower’s trade shows anywhere, the Farwest Show. Whatever problem lies on the horizon, you can bet OAN is already working on solutions.
FRANK GARDNER is a writer and business consultant in Arroyo Grande, CA.
OW - May/June 2006 |
