by Dwain Hebda
Groundwater concerns prompt conservation, new technology
Ed Swaim clicks a button on his laptop, putting in motion a computer model of the Mississippi River Valley alluvial aquifer, the most important source of groundwater for agricultural purposes on Arkansas’ fertile Grand Prairie. The animated model shows projected future water consumption and its impact on the aquifer, the mass of water being one color and the dry perimeter of the underground ocean being another.
Put in motion, the dryland color swallows up most of the water area like a runaway virus. The timeline is 30 years.
“The main thing to understand about it is that it’s not just a straight-line progression of the problem,” he says. “There’s not a date or specific time when groundwater in general won’t be available, because it’s being drawn down gradually at a pretty good pace.” — Ed Swaim
The audience lets the image sink in, in stunned silence, until one attendee raises his hand. “Run that again,” he says flatly as others nod, not believing what they just saw.
Swaim, executive director of the Bayou Meto Water Management District and former chief of the Water Resources Management Division for the Arkansas Natural Resources Commission, is no alarmist. He doesn’t have to be, the numbers do that all by themselves.
“The main thing to understand about it is that it’s not just a straight-line progression of the problem,” he says. “There’s not a date or specific time when groundwater in general won’t be available, because it’s being drawn down gradually at a pretty good pace.”
“When [ANRC] did the [state] water plan, we calculated out the ability of the ground to supply the water that we use now and that we would end up having to use in the future. By 2050, and that was a planning horizon for the water plan, we determined 80 percent of the water that is going to be needed in 2050 would essentially not be there in the aquifer.”
You can’t raise a crop, obviously, without water and Arkansas’ dance with natural resources is as old as farming in the state, which is to say well before white settlement. But it wasn’t until rice came into widespread cultivation in Arkansas – along about the 1920s – that this farming fact of life came under scrutiny. Rice is a water-intensive crop, but with technology and attitudes being what they were at the time, little concern was given about conversation by the average producer, given the seemingly limitless underground water supply.
Rice irrigation in Prairie County. Photo provided by Arkansas Farm Bureau.
Ag scientists, however, took note of the quantities of water being applied in rice production, as well as other crops, even in these early days.
“What we saw in the 1920s was 10-15 years after people started irrigating rice, water levels were not recovering each year. You’d see it go down a little bit, down a little bit,” Swaim says. “In the 1920s, some U.S. Geological Survey folks came to Arkansas and started measuring water levels. They would take measurements on the Grand Prairie primarily and year to year they were seeing a draw down.
“That started this long period of really good science and good measurements. We have continued to do that to the present day and now we measure hundreds of wells all over the state in all the different aquifers.”
Over time, the USGS’s efforts have been augmented by similar monitoring by the Arkansas Natural Resources Commission and the Natural Resources Conservation Service. Other groups have also chimed in, on a more limited scale. The upshot of these efforts is sobering.
“The pattern is, the farther away from a large river you are, the less saturated thickness you have in your groundwater,” Swaim says. “In our district, for example, there’s an area between Lonoke and Carlisle, and it’s a long triangle north to south, where the alluvial aquifer is down to about 10 percent of its capacity.”
The concerns over groundwater depletion aren’t solely environmental. Rice farmers absorb additional expense as the primary aquifer is depleted, drilling deeper wells to reach the next aquifer. These projects can run $100,000 or more to drill and equip, not to mention the ongoing costs to operate the pumps.
This has turned many farmers’ attention to sources of surface water, such as tail-water recovery systems catching runoff and above-ground reservoirs. However, these options also are not cheap and carry the additional drawback of eating up land that would otherwise be producing a crop.
Given these challenges, and with the White and Arkansas rivers rolling through the heart of Arkansas’ breadbasket, creating an irrigation system that draws from these rivers is an idea that has been bandied about for decades.
Soybean field near Moro. Photo courtesy of UA Division of Agriculture.
“There are two projects over the last 15 to 20 years that would go a long way towards alleviating demand on the aquifers. Those would be the Grand Prairie Irrigation Project and the Bayou Meto Irrigation Project,” says Evan Teague, vice president of commodity and regulatory affairs for Arkansas Farm Bureau. “In the update of the state water plan, there were some figures that said if you could put the Grand Prairie in place and Bayou Meto, too, you would reduce ground water consumption by 15 percent. That would take a large chunk of pressure off those aquifers.”
Both projects have had their share of controversy. Environmental groups sued on the basis that pumping out of the White River would negatively impact habitat and just as soon as those ran their course, someone sighted (or claimed to see) an ivory billed woodpecker, thus raising the same hue and cry over the Bayou Meto project. Today, legal issues aren’t the primary stumbling block, funding is.
“On the Bayou Meto project, tens of millions of dollars would go a long way,” Teague says. “On the Grand Prairie, hundreds [of millions]. The delays and construction costs over the last 10 or 15 years have driven up the cost of the project. Had we been able to complete these projects 15 or 20 years ago, we probably wouldn’t be talking about this issue as much as we are today.”
Morning irrigation at a farm in Scott.
UA Division of Agriculture photo by Mary Hightower
Rice farmers have frequently been painted as the bad guys in this debate, portrayed as uninformed self-servers mindlessly siphoning every drop they can point their pipes. A 2002 New York Times article on the subject offered a prototypically stinging lead, “Rice farmers … are on the brink of draining one of Arkansas’ biggest aquifers dry.”
Not fair, says Teague, noting today’s ag producer is employing technology and farming techniques that go well beyond what most people realize, all in the name of wise water usage.
“On the Bayou Meto project, tens of millions of dollars would go a long way,” Teague says. “On the Grand Prairie, hundreds [of millions]. The delays and construction costs over the last 10 or 15 years have driven up the cost of the project. Had we been able to complete these projects 15 or 20 years ago, we probably wouldn’t be talking about this issue as much as we are today.” — Evan Teague
Many are turning to precision grading and zero-grade techniques, which configure the slope and construct of fields to use water more efficiently and, combined with furrow irrigation, often allows other crops to be rotated in with rice.
Ag technology is improving right along with these farming practices to further boost water-use efficiency.
“Over the last five to 10 years, farmers have adopted the use of polypipe and pipe planner which is a program where you take the dimensions of your field, put it in the program, the type of crop you’re growing, the amount of water you use and your row spacing, and this program will determine the spacing for the gates you need to poke in the pipe,” Teague says. “This lets you water the rows so that you don’t have any runoff come back in the field. You’re more efficient in water use because and you’re using only the amount of water you need and not wasting it.”
Teague also pointed to research by the University of Arkansas Cooperative Extension Service to develop a system of “smart fields” that provide feedback to the producer on water needs.
“They are looking at using soil moisture probes and weather stations connected to irrigation pumps and meters,” Teague says. “Those soil moisture probes are helping determine when to turn pumps on and off based on the moisture content locations at the end of the field. That’s a pretty sophisticated program.
“I think conservation measures are where we in agriculture don’t do a good enough job of tooting our own horn, so to speak, and we preach to the choir a lot. We know what we’re doing, but as far as people that aren’t directly involved in agriculture, the general public and our consumers, they don’t understand. The way I put it is, agriculture is in the next technological revolution, and it’s really a quiet one.”
