BOONE - With each 1-inch rain fall, the 30-by-96-foot high tunnel on the Nature Road Farm will shed 900 gallons of water from each side of the gothic-styled structure.
And without a catchment system in place, the bulk of that water would run under the hoop building's walls and drown the plants inside.
That's why Randy and Linda Naeve, now in their second year of raising vegetables for a community supported agriculture operation just north of Boone, decided to do something about it.
-Messenger photo by Larry Kershner
Linda Naeve explains how the water catchment system works on a high tunnel structure at Nature Road Farm, a mile north of Boone.
Their high tunnel structure was finished just days before they hosted a field day Monday night on their farm to show others how the water catchment system works and how they recycle that collected water back into the tunnel to water plants.
"We didn't do this to save money on water," Linda Nave told a group of 30 visitors at the field day.
Rather, they were looking for a method for controlling the runoff water, allowing them to plant closer to the sides of the tunnel's interior, as well as control diseases by keeping the tunnel drier.
Naeve has been working for the past few years at the Iowa State University Research Farm in Lewis studying how high tunnels work and knew from experience how rainwater, flowing down the domed tops of the tunnels, puddled at the base and seeped inside.
With the idea of catching the water, she researched what others around the country were doing about the problem.
"I was surprised to find that no one anywhere was doing this," Naeve said. "It seems like such a simple thing."
Naeve said she found only one person in any research facility was managing storm runoff, but was channeling the water away from the structure, not collecting it.
With assistance from Shawn Shouse, an ISU ag engineer, she designed a collection system for a Quonset-style high tunnel on the Lewis farm and liked the results.
So when the Naeves built their gothic-style structure, they applied a storm gutter system along the long axis of the building, dropping eight inches as the water flows down the 96-foot length and empties into a 1,000-gallon tank. There are gutters and tanks on both sides of the building.
The water is then pumped through a slow, trickle system inside the tunnel to water the plants.
Naeve said because ambient temperature is higher inside the domed tunnel, the interior is similar to a desert environment.
The pump streams about five gallons of water per hour and will be able to provide moisture to as many rows as needed.
They also have an independent water source for when the tanks are empty.
The water system cost about $1,100 to install.
Most of those attending Monday's event came to learn about the system. Others, who operate their own CSAs, asked questions about management of the produce.
David Saupe, who lives just eight miles north of Nature Road farm in rural Boone, said he and his wife has a smaller tunnel system for their garden produce and was impressed over how the system works.
He said his garden system is just for growing their own food.
The Naeves farm 1.5 acres of family land that was formerly hay ground.
They conduct regular soil samples and have designed a four-year rotation system for their crops to combat plant diseases.
They have 70-member CSA and delivers produce to clients for 16-weeks through summer and fall.
They are not certified organic, use commercial fertilizers and employ an integrated pest management system.
Contact Larry Kershner at (515) 573-2141, Ext. 453 or at firstname.lastname@example.org.