Aquifer levels falling sharply After enduring almost three months this summer without a substantial rainfall, some Mid-South farmers are wondering if the Mississippi Delta's seemingly endless supply of water could run out.
While water supplies in the Mississippi Delta are showing the signs of heavy use, Yazoo-Mississippi-Delta (YMD) Joint Water Management District Executive Director Dean Pennington says his agency is taking steps to insure the Delta's supply of quality water remains available to farmers. As groundwater levels and stream flows are dropping, YMD is aggressively working to balance the region's water supplies with its water needs, Pennington says.
According to Pennington, about 90 percent of agricultural water use in the Mississippi Delta comes from groundwater in the Mississippi River alluvial aquifer. The water from this aquifer is used on approximately 100,000 acres of catfish ponds, 275,000 acres of rice and 1 million acres of cotton and soybeans, combined.
Before 1998, Pennington says, water levels in the aquifer were dropping about one-third of a foot per year. "This was not an alarming rate, but it does indicate that we will gradually use up the groundwater supplies. The dry years of 1998 and 1999 produced groundwater level declines of about one and one-half feet per year and the summer of 2000 looks like another big water use year," he says. "If we were to use up this water supply, Mississippi would lose the tremendous economic benefits it provides."
Currently, YMD is addressing aquifer overdrafts and the maintenance of stream base flows on two fronts. The water management district is advocating a more efficient use of existing water supplies through conservation efforts. It is also trying to develop new, dependable surface water supplies to supplement existing water sources.
"Conservation of any natural resource in limited supply is always the first, most effective option to make existing supplies do more," he says. "Water conservation is not a new idea and many organizations and agencies, like the Natural Resources Conservation Service, have been aggressively promoting conservation for many years. YMD is working with traditional conservation organizations to promote land use practices that reduce the amount of water needed to maintain a crop or pond."
Most of the water conservation practices the water management district is advocating are fairly well-known. They include land forming, tail water recovery systems and storage management to capture rainfall in catfish ponds.
Use of these and some other conservation practices cannot only conserve water, but often can increase yield potential and reduce production costs. Conservation practices, of some kind, can potentially be used on every acre of farmland in the Delta, Pennington says.
Water conservation efforts can go a long way to preserving water supplies in the Mississippi Delta. However, in those areas of heavy groundwater use, or where the available groundwater has declined significantly, new surface water supplies may need to be developed.
Pennington says new surface water supplies will be used to replace the use of groundwater in key areas across the Mississippi Delta. YMD, he says, is currently working to develop new surface water supplies in those areas where groundwater use is heaviest, groundwater declines are largest, and where the opportunity to develop, store or transport surface water will be easiest to develop.
New surface water supplies are being developed in two major ways, according to Pennington. First, is the placement of low water weirs in several locations to store more water in natural channels and lakes. This extra storage will capture and hold rainfall and irrigation runoff, which can then be used to irrigate land adjacent to the enhanced water supply.
Water stored in these lakes can also be released during dry periods to add to low flows in Delta streams. Several lakes and channels located throughout the Delta have been identified by YMD as candidates for this project. The agency is also inviting landowners to contact them with suggested locations for surface water storage improvements.
Another way YMD is developing new surface water supplies is with interbasin transfers. Interbasin transfers move water from river systems with more water than they need, into river systems that need additional water for irrigation. "This work is just beginning, but it has the potential to supply thousands of acre-feet of water per year to the Delta," Pennington says.
"Regional water use analysis indicates that a combination of aggressive implementation of conservation practices, the placement of storage enhancing weirs, and the importation of modest flows of water into interior Delta streams, will allow the region to have sufficient water to meet the Delta's needs for decades to come," he says.
For more information on conservation management practices, contact the YMD Joint Water Management District, the Natural Resources Conservation Service or your local Cooperative Extension Service office.
Cotton producers are being reminded of the importance of cutting stalks after they complete the 2000 harvest.
"The boll weevil is down, but he is definitely not out," says Blake Layton, Extension entomologist with Mississippi State University. "By destroying cotton stalks as soon as possible after harvest, growers can greatly aid the boll weevil eradication effort."
Layton said all four of Mississippi's Boll Weevil Eradication Program regions have made "great progress" toward eradication, but that progress can be eroded by leaving stalks - and, thus, a potential boll weevil food source - standing after harvest.
"This year's crop and environmental conditions also make early stalk destruction more important than usual," he noted. "Because of the dry season and the earlier harvest, fall rains could stimulate rapid regrowth. Where this occurs before frost, the BWEP will be forced to continue treating, even if the field has been harvested.
"Obviously, this will result in increased cost, and some areas are already seriously over budget."
Mississippi farmers will not receive credit for early stalk destruction this year since none of the state's four regions are in fall diapause programs that occur in the initial year of operation.
However, growers in the state will face a penalty of $5 per acre for stalks that have not been destroyed by Feb. 1.
Currently, all of the cotton growing areas of Mississippi and Louisiana are in their second, third or fourth years of boll weevil eradication. Growers in all but four counties in Arkansas and in southwest Tennessee are in their second year and producers in the central portion of west Tennessee began their program in August.
Farmers and landowners in southeast Missouri recently failed to approve a program in their region by the necessary two-thirds vote. Ballots for a similar referendum in the four counties in northeast Arkansas that are not involved in an eradication program are scheduled to be counted Sept. 25.