By Margarette Chavez
Wilson County News

Local agricultural producers aren’t the only ones who find “reaping what they sow” rewarding — so does the South Texas Weather Modification Association (TSWMA).

They see the rain they harvest from “cloud seeding” as a welcome reprieve from the region’s blistering, parched summers, and as an advantage to the water resource management efforts of the counties they serve: Wilson, Frio, Atascosa, Bee, Karnes, Live Oak, McMullen, Bexar, Medina, and Bandera.

Seeding benefits everyone: “ranchers and city people” alike, explained Wilson County board member John Larrison. It reduces pumping, cuts irrigation costs, and recharges the aquifer.

Although the program functions year round, activity occurs almost exclusively in the summer since during the winter, cloud formations aren’t conducive to seeding. As a matter of fact, Bexar, Medina, and Bandera, the three newest counties added to the TSWMA target area, are only on board May through October.

“A lot of people think of cloud seeding as a way to bust a drought. In reality, if we’re in a drought there are no clouds so we don’t do much either,” said meteorologist Todd Flanagan. “We can only work with what’s out there. We find something that is developing [rain cloud] and give it a boost to make it last longer — grow a little bit bigger.”

Just how big the association can make a cloud grow has been a concern for some. Flanagan said he was aware of the rumors regarding STWMA’s alleged con-tribution to the most recent flood, and he wanted to dispel any myths.

“Even if we had done some seeding, I’m not sure that we would have added a significant amount [of rain] to cause flooding,” he said. “But we weren’t even up in the air at the time so all of these accusation of us casing the flood are false. They’re just not founded.”

Flanagan asserted seeding took place on June 30, 2002 in Frio County, but the heavy rains didn’t start until the next day. The effects of cloud seeding usually start approximately 20 minutes after the seeding has taken place.

Then there’s the idea of robbing Peter to pay Paul, added Flanagan. “People think if you seed you’re robbing someone else of rain. That’s not how it works,” he said. “Seeding tends to increase the lifetime of the cloud so you’re getting more from it; another area isn’t get-ting robbed of moisture.”

STWMA employs a base seeding technique in which silver iodide is injected into clouds identified as potential rain producers. Seasoned pilots pop flares from single engine Piper Comanches to free the smoke that delivers the silver iodide. In a large cluster of potential rain clouds as many as 10 – 14 flares could be released, smaller clouds would demand a lesser number. If there’s no response, the seeding is halted. Flanagan doesn’t believe in wasting flares.

For the pilots, seeding presents a dangerous situation. Yet the program has had a 100 percent safety record since 1998, according to Chief Pilot Tim Pickens. The statistic is signifi-cant because these pilots are flying in weather other pilots avoid.

The program calls for experience. According to Pickens, STWMA’s five pilots have a combined total of 51,000 flight hours. They all have a background in flying by instrument panel and weather modification.

The pilots do no top seeding since the procedure requires twin engine planes that the association doesn’t own. According to Flanagan, that isn’t a drawback since “base seeding works best in this area.”

What is somewhat of a limitation is the lack of direct ground measurements indicating how much water has been produced. That would certainly work to convince skeptics of the program’s value. However, Flanagan points out that radar observations and mathematical analysis are available.

Flanagan said the analysis compares a cloud that has been seeded with a one that has been modeled to be identical, but hasn’t been touched. Then the analyst follows the two life cycles of each and compares. He can then determine the unseeded cloud lasted for x amount of time but the seeded cloud lasted x plus 45 minutes, for example.

According to STWMA Secretary Mike Mahoney, evaluation for the 2002 program indicates 74,492 acre feet of water was produced at a cost of $2.91 an acre foot.

In terms of geographic target size, STWMA is the second largest program of its kind in the state. Its base of operations sits off the beaten path at the airport in Pleasanton in a 7,400 sq. ft. hangar/office building that comfortably houses four aircraft, the meteorologist and five pilots

A nonprofit association, funding comes from the water districts: the Evergreen Underground Water District, the water districts for Bee and Live Oak counties, and McMullen County’s Commissioners Court.

“We have a set charge of approximately 3.5 cents per acre. So in the case of Evergreen, you take those four counties that make up their water district and whatever the acreage is you multiply by 3.5 cents; that’s what they contribute,” said Flanagan.

Bexar, Medina and Bandera pay 4 cents an acre through the association’s contract with the Edwards Aquifer.

Additionally, the Department of Agriculture, [state] furnishes matching funds. For every dollar the association spends on infrastructure, equipment, fuel, insurance, etc., the Department of Agriculture returns 50 cents. However, due to current budget constraints those funds are in jeopardy.

“We’ll be more than happy to take our fair cut to help the state budget crisis. We’ll tighten our belts and make it [weather modification program] work,” said Mahoney. “If they [the state] impose a 7-10 percent cut, we’ll still be in excellent
shape.

Thanks to the board’s shrewd fiscal policy, the association owns the building, the radar, and the four planes.

“This is a cost-effective program,” said Mahoney. “It’s part of our water conservation efforts and, it prepares us in case of drought.”

Mahoney said that every ef-fort would be made to continue the program.
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