With an ongoing shortage of water for irrigation, South Texas farmers are looking for cost-effective ways to make every drop count. Now, thanks to a special grant program, Rio Grande Valley growers can apply to be one of the 32 growers selected to participate in a surge valve project and acquire these water-saving devices at a fraction of what they normally cost.

To be specific, the first 32 farmers to apply and be accepted for the "Valley Water Saving Project" are eligible to purchase up to two surge valves for as low as $300 each. The valves normally sell for $2,000.00. Interested growers can apply to any irrigation district in the Valley or use the contact information listed below.

Floods and droughts are common occurrences in the Lower Rio Grande Valley, but over the last three years a lack of substantial rain, falling reservoir levels and delivery problems associated with an international water treaty with Mexico have combined to create a serious water shortage. Farmers, among other water stakeholders, have been hard hit by water availability.

As irrigation water levels diminish and the cost of water increases, Valley farmers are desperate for answers on how they will be able to sustain agricultural operations in the years ahead.

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As drought conditions have intensified in recent years, researchers have accelerated projects designed to grow healthier crops with less water. Ongoing drought-related projects have also included irrigation studies involving new methods and technologies designed to conserve water.

While surge valves have been around for a long time, until recently the cost of the valves and the ability to access and purchase irrigation water at affordable prices have kept many growers from taking a great interest in any new irrigation technology that required investment capital.

But as water becomes harder to get and more expensive, these technologies, including surge valves, are gaining popularity as the cost of investment versus the cost and availability of water resources begins to balance out.

Study indicates technology's value

In 2011, the Texas A&M University Department of Agricultural Economics and Texas AgriLife Extension Service conducted a comprehensive study in the Lower Rio Grande Valley titled the Agricultural Water Conservation Demonstration Initiative (ADI project), a multi-faceted effort involving the Texas Water Development Board, the Harlingen Irrigation District, several South Texas agricultural producers, Texas AgriLife Extension (Extension) Service, and other agencies.

It was designed to demonstrate state-of-the-art water distribution network management and on-farm, cost-effective irrigation technologies to maximize surface water use efficiency.

In 2010, as part of the larger study, a furrow versus surge valve technology demonstration associated with the ADI project was completed to analyze potential water application and irrigation costs scenarios in cotton production.

At the time, irrigation water was sold to growers was $1.17 an acre-inch or $14 per acre- foot. The cost of surge valves at the time of the study was approximately $1,800. The results of the project concluded that while the investment required by growers to acquire and use surge valves in their cotton fields would have been minimally higher than purchasing water at prevailing prices, and considering irrigation water was readily available in 2010, only a few growers expressed interest in investing and converting to surge valve technology.

But the study, conducted by Texas A&M Extension specialists Mac Young, Steven Klose and Valorie Reynolds, correctly predicted that water would become harder to acquire in and prices would eventually rise. They concluded that the cost of purchasing and changing to surge valve irrigation would not provide an immediate cost benefit compared to traditional furrow irrigation methods, but it would help conserve water. They further concluded a time was coming, as water supplies diminished and the cost of water increased, when converting to surge valve technology would not only be cost efficient, but also would lower overall production costs.

According to water officials in the Valley, that time has arrived. With limited irrigation allocations, many growers have been forced to purchase water outside their districts at a much higher cost. With water availability at a 20-year low, the cost of converting to new irrigation technologies appears to be a less expensive alternative.

Tom McLemore, project manager at the Harlingen Irrigation District, was involved in the 2011-2012 study as project manager on the cotton fields selected for the surge irrigation technology evaluation. In addition, he grows sugarcane and is one of a few Valley growers who utilize surge valve technology on his farm.

"While water prices have not increased significantly over the last year or two, many growers have been forced to purchase water out of district because of water shortages. In these cases they are paying $35 to $60 an acre-foot, and this justifies the acquisition costs of surge valves," McLemore said. "These surge valves also help growers stretch their allocations, so not only is there a financial benefit to using the technology, but it also reduces the amount of water used on a field, and that's good for everybody."

How surge irrigation works

Surge irrigation uses a surge controller butterfly valve placed in the center of the top of the field with gated pipe leading out of the valve going both directions. The valve works by oscillating water from one side of the valve to the other at determined intervals.

The alternating flow of water on each side of the valve causes an intermittent wetting and soaking cycle in the irrigated furrow. This causes soil particles to settle to the bottom of the furrow and can reduce the water intake rate of the soil. With a reduced intake rate, the water can advance down the furrow faster giving the field a more uniform water application, while requiring less water for an adequate irrigation.

"If it takes 12 hours to run 100 rows (furrows) utilizing constant flow irrigation, with a surge valve it can be set up to take 24 hours to run 200 rows, first to one side of the valve and then the other side of the valve or irrigation line. This breaks the water application up and allows the surface of the field to seal rather than having so much infiltration or evaporation," McLemore explained.

He says tests have discovered that surge valve irrigation not only lowers the infiltration rate but also helps on the tail water so excess water doesn't run off the end of the field, meaning it takes less water to complete an irrigation cycle.

Another benefit of surge irrigation is that valves controllers allow the grower to choose the durations of the irrigation oscillations from one side of the field to the other.

With the upcoming standards regarding water quality, using best management practices in irrigated fields to reduce soil loss, nutrient loss, and water usage, is becoming more important. Studies of surge irrigation have shown significant benefits to increased irrigation efficiency, yield maintenance while using less water, reduced nitrogen leaching in some fields, and reduced sediment loss.

While conventional irrigation and surge irrigation may produce equivalent yields in the end, trials indicate surge valves used half the amount of water over the entire irrigation season compared to conventional irrigation to achieve the same results.

"This could help Valley growers avoid purchasing out of district water during dry years or when adequate water is just not available," McLemore added.

Water officials say the 32 growers selected to participate in the current surge valve program must agree to attend one of two scheduled meetings where proper use of surge valves will be offered if they want to receive the full cost discount of the valves. These programs will be offered Tuesday, Sept.  17, and/or Wednesday, Sept. 18. Both will be held at the Rio Grande Center for Ag Water Efficiency, located next to the Harlingen Irrigation District’s river pumping plant.

"What we hope to accomplish with this program is to introduce surge valve technology to more local growers. Once the technology is employed in a real farm setting, others will hear about it and this in turn could encourage other growers to look at the technology as a way to conserve water and even cut irrigation costs," McLemore said.

The Rio Grande River Water Authority applied for the grant to support this program after field demonstrations showed that using surge valves in furrow irrigation can significantly reduce water consumption across a variety of crops. The demonstrations — conducted by the Texas Project for Ag Water Efficiency (Texas AWE) — documented water savings of up to 52 percent in sugarcane, 31 percent in seed corn, and 28 percent in cotton.

Growing sugarcane in the Lower Rio Grande Valley uses some 252,000 acre-feet of water per year, and irrigated cotton about 111,000 acre-feet per year. Based on Texas AWE findings, using surge valves to irrigate these crops could save around 110,000 acre-feet of water per year in the region, an amount equal to about 40 percent of current municipal demand in the entire Valley.

Interested growers can contact any irrigation district office in the valley for more information or can call Karen Ford at Water PR at 512.477.5445, or Tom McLemore, Harlingen Irrigation District at 956.367.6599.

 

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