As the 2006 growing season opens for business, Arkansas farmers want no repeat of last year's dry conditions. Recent rains have eased drought concerns but not done away with them.
“Some time ago, we began to notice a long-term trend of less water flow in the state,” says John Terry, director of the U.S. Geological Survey's (USGS) Arkansas Water Science Center. “It's gotten to the point that (in mid-March) readings on 26 of our stream and river gauges were at all-time lows. Some of those gauges have been in place for 30 years.”
That news, “is huge,” says Todd Fugitt, Arkansas Natural Resources Commission (ANRC) geologist. “It points out what's been happening hasn't been a minor drought.”
In fact, 2005 was the second worst drought since 1895 when records began being compiled.
Adding to consternation is a March 30 press release from the Army Corps of Engineers. In it, farmers are alerted that due to drought conditions in the Arkansas River basin, “pools 2 and 5 may be unable to fully maintain their irrigation pool elevations this growing season. Therefore, the agency is advising farmers who rely on those pools to consider their choice of crops and take the possible scarcity of water into account.”
Pool 2 extends 38 miles upstream from Tichnor, Ark., in Arkansas County to Joe Hardin lock and dam near Grady, Ark., in Lincoln County. Pool 5 extends some 21 miles upstream from Wright, Ark., in Jefferson County to David D. Terry lock and dam near Scott, Ark., in Pulaski County.
According to the Corps, the Arkansas River remains in a Level 2 drought (with Level 4 being the most severe). Any gains from recent rains are expected to be short-lived.
“Most of the Arkansas River's flow in the dry summer months comes from rainfall in Oklahoma and Kansas that has been stored in reservoirs in Oklahoma. This flow is released either as flood releases or hydropower generation. However, Oklahoma reservoirs are currently holding no flood storage.”
While forecasts call for some summer rainfall relief in Arkansas, things look bleak in Oklahoma. As a result, “hydropower releases this spring and summer could be minimal on the Arkansas River as (water is conserved) by supplementing hydropower demands with alternative sources of electricity.”
Unlike surface water, groundwater doesn't have extremely dramatic year-to-year level fluctuations. Groundwater involves more robust systems that don't respond as quickly to a drought or recharge. But recent dry conditions and over-pumping have still had an effect.
On average, Arkansas gets 49 inches of rain a year. Of that, only a small amount — around 3 inches — percolates down into the groundwater system.
“Surface water problems show up quickly and in obvious ways — flooding, drying up of streams or lakes, pump intakes need to be deeper,” says Fugitt.
“Groundwater is much more subtle. For instance, in the Delta we usually see a bit more than a 3-foot decline in the alluvial aquifer water level. That happens between spring and fall during the irrigation season.”
Last year during that time period the state's alluvial aquifer experienced a 4.4-foot decline.
“That doesn't sound like such a big deal. However, when spreading out a foot of water over the entire Delta, that's a tremendous additional loss of aquifer volume.”
Over the winter, there is recharge of the aquifer although it rarely reaches the original water level.
“Most years, we lose 3 feet and recharge a couple of feet. There's a loss of a foot of water in the aquifer annually. The drought adds to the deficit, but the real issue with groundwater is we're above sustainable yield every year.”
On the heels of such a dry 2005, Fugitt hopes the alluvial aquifer will get back half of the lost 4 feet in recharge. “It would be great to get the normal recharge. I hope 2 feet is a realistic target. We're glad to see the latest rains, but we probably need a lot more to get the normal recharge.”
Last year, many reports of water problems reached the ANRC. Such reports were frequently from rice farmers worried with falling on-farm reservoir levels.
“I'm hopeful that the rain showers we had in March will continue and reservoirs won't be in a (poor) position this growing season,” says Earl Smith, ANRC Water Resources Management Division chief. “But we're certainly concerned. I saw — and spoke with many people who saw — dry river bottoms in December and January that no one could ever remember being dry. Those instances are really alarming.”
Without quick, substantial rainfall Smith foresees more calls from down-stream landowners saying, “‘I'm not getting my share of the water. What can be done?’ There is a provision that, if the (ANRC) declares a shortage of water exists, allocation procedures could be put in place. Those look at how water could be divvied up to as many people as possible. Now, that's an extreme situation, one we'd take only in severe emergencies.”
The longer the drought continues the more requests for such action, though. Entering January and February, as low as water levels were, “we could see that a dry spring could present such an emergency. However, we've been very encouraged by the rains we've gotten and hope they keep coming.”
Smith says water calls typically come from areas that are heavily irrigated coupled with groundwater levels trending down. The far northeastern part of the state — the St. Francis basin — tends to be the best place for water.
“Water levels there haven't dropped nearly as much as counties like Lonoke, Prairie and Arkansas. And it isn't just agriculture concerns. We heard from several municipalities last summer. Lake levels were getting very low and they wanted to know what could be done to supplement their drinking water.”
Among the most dramatic surface water drops was the White River. “Anyone who crossed the White or saw any of (the lakes it services) saw how low it was. In the west, Fort Smith had drinking water reservoirs that were extremely low. Perryville was in the same bad shape. Really, though, the drought effects were distributed pretty well across the state.”
By far the largest user of Arkansas groundwater is Delta-area irrigation, primarily from the alluvial aquifer.
“That's the rice wells in the Grand Prairie and into the northeastern part of the state,” says Fugitt. “The Sparta aquifer is deeper and more confined. It doesn't have nearly the volume of the alluvial. From that aquifer, removal of water is roughly equal between agriculture, industrial and municipalities.”
A disturbing trend — particularly in the Grand Prairie — is there are still wells being drilled into the Sparta aquifer for irrigation.
“That aquifer is already above sustainable yields. Since the Sparta is being used for municipal purposes, it isn't a long-term answer for agriculture.”
Well measurements are taken in the spring. That's because usually by March or early April, the aquifer has received its most significant recharge and readings must be taken before irrigation begins in earnest.
“Once the pumps are turned on, water levels are immediately pulled down and measurements are skewed,” says Fugitt.
Most of Fugitt's readings aren't from gauges. “We do use electric water level meters, but we take most measurements with steel tape and a piece of chalk. You put some chalk on the tape, run it into the well and reel it back up. The water cut shows up on the tape and you know what the level is.”
Measurements have been taken that way for decades. During both spring and fall, Fugitt and colleagues take several thousand such measurements across the state. They also check a subset of wells monthly.
Among other things, USGS' job in the state is to monitor stream flows, groundwater levels and water quality. This means frequent field trips for staff to measure stream flows and service instruments that transmit data via satellite to a downlink at the state office. That data — from 110 real-time stations — is available at http://ar.water.usgs.gov.
On the groundwater side, USGS monitors some 300 wells tapping the state's major aquifers.
“We have a good handle on what's typical for water levels in both the Sparta and the alluvial,” says Terry. “Both have experienced tremendous draw-downs resulting in huge cones of depression from over-pumping. There have certainly been problems on the surface and sub-surface as a result of a shortage of rainfall. That hasn't only translated to issues for agriculture and municipalities. Forested areas are dry and are much more vulnerable to wildfires.”
The data currently being collected is “very important,” says Fugitt. “We'll soon know how hard the 2005 drought was on our aquifers. It'll be the summer before those numbers are ready, but it's safe to say the aquifers took a hit.”
Terry says it's fair to say the growing season is beginning “in a shaky situation, water-wise. Although there have been bands of rain across the central and southern parts of the state, the northwest — and northeast, to a lesser extent — hasn't gotten the kind of rainfall needed to refurbish soil moisture. East and west of Crowley's Ridge, producers will be starting in pretty dry conditions. If rainfall doesn't come during late spring and early summer, that area will be hard hit during the summer months.”
‘Sustaining aquifer’ wells to be metered
Starting Oct. 1, flow meters will be required on any well tapping a “sustaining aquifer” in Arkansas. Most irrigation wells in the state tap into the alluvial aquifer. As the alluvial isn't classified as “sustaining,” wells drawing from it are exempt.
“A sustaining aquifer is tagged as one that is essential for life — drinking water, essentially,” says Todd Fugitt, a geologist with the state's Natural Resources Conservation. “While the alluvial has some municipal wells in it, its primary historic use has been for agriculture.”
For more information on the new metering regulations, visit http://www.aswcc.arkansas.gov/well%20metering.htm.