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By Lana Robinson
Field Editor
Ralph and Glen Kellemeier's cotton crop is thriving this year, thanks to a subsurface drip irrigation system and treated wastewater provided by the City of San Angelo. The brothers' farm near Veribest was the site of a July 20 tour demonstrating the feasibility of the effluent water applied below the ground surface. About 60 people showed up to observe the progress of the two-year project, largely funded by the Natural Resources Conservation Service and the Bureau of Reclamation.
"Excess effluent water from San Angelo has been used by farmers in the Veribest area for several years now (since 1999) as has drip irrigation, but the two have not been used together," said Steve Sturtz, Extension agricultural agent in Tom Green County and one of the program's coordinators. "This is the first documented demonstration of its type in the nation."
The scheme provides a more reliable source of irrigation water for the Tom Green County Water Control and Improvement District No.1, as its draw down from the supply reservoir can be limited in times of drought. And in return, the city and district exchange water allocations from the source, the Twin Buttes Reservoir, in the amount of effluent water supplied by the city. Wastewater from San Angelo flows through more than 60 miles of canals before getting to the 30-acre plot on the Kellemeiers' farm. The water is filtered again before it flows through underground hoses to water crops.
"Obviously when we go through a tape this size, the system has got to be clean and the water has got to be pretty pure to go through this kind of system and get to the cotton plant," said Sturtz.
Sturz said the goal was to document the efficient use of the wastewater.
"It's all going into production," he noted.
Another goal of the study, Sturtz said, is to address problems previously encountered by those attempting to use wastewater through driplines. Impurities such as algae from the holding ponds and debris picked up in the open irrigation canals are the culprits.
"The demonstration plot allows farmers to learn to manage around these problems without wasting their own dollars to do so," said Sturtz. "Drip irrigation loses much less water to evaporation and runoff than more conventional systems. Successfully using wastewater through drip systems would be a boon to stretching scant water resources in the dryer areas of the nation where every drop of moisture counts."
Chemical injection is needed to keep the pH right for the crop. Also, Eco-Drip Irrigation of Garden City had to specially-design the system, and achieve a delivery rate adequate to redistribute water at a rate of 350 gallons per minute to the four zones on the Kellemeier test plot (a 10-gallon-per-minute delivery rate coming from the canal compared to well water, which would only need to redistribute at a rate of 3 to 5 gallons per minute).
Forty-three miles of underground drip tape and 1.5 miles of PVC pipe were installed. In all, the system, and expense for running electricity, cost $1,660 acre.
"Cost is the biggest factor," said Ralph Kellemeier, who uses overhead irrigation on his other cotton, wheat, milo and corn crops.
Although initial costs to install subsurface irrigation are high, Yantis Green, Tom Green County Water Control and Improvement No. 1 district manager, says the farmers will save money over the long-haul.
"You use 70 percent less water and produce the same crop, so it makes the water go further," said Green. "You run the water underground to the crop instead of out in the open, and you don't lose as much to evaporation."
2004 yield data will be collected for comparison with next year's crop.
"With the subsurface irrigation, the longer it's in, the better the results," Glen Kellemeier noted.
