The Grand Prairie Area Demonstration Project (GPADP) is a comprehensive water management plan designed to protect and preserve the Alluvial and Sparta Aquifers. This project also allows the continued irrigation of current agricultural crops and reduces further depletion of groundwater aquifers, while continuing to provide critical benefits for the millions of waterfowl, which annually migrate through the region.
The project utilizes excess surface water and water from the White River to supplement a network of on-farm tailwater recovery systems. This supplemental system will be used to fill on-farm reservoirs that store the water, which supplies at least a portion of each farmers' irrigation needs.
Where is the Grand Prairie Area Demonstration Project located?
Arkansas' Grand Prairie is an area in the east-central portion of the state situated between the White and Arkansas Rivers. Existing with relatively flat topography and topsoil underpinned with alluvial clay, this former grassland prairie along with its hardwood bottomlands, were transformed during the past century into the state's most productive agricultural region.
Why is it needed?
By 1915, some 10 years after rice farming began in the area, the Alluvial Aquifer's groundwater was being tapped at a rate that exceeded its ability to recharge. Though recharge of the Alluvial Aquifer came from several sources including rivers, streams, bayous, rainfall and percolation, the water table decline was never reversed.
During the past decade the Sparta Aquifer has been tapped for agricultural and commercial water use, because the Alluvial Aquifer had shrunk and could no longer keep pace with region's demand. The region's groundwater problem was pointed out in a project study in the mid-1980s. Officials from the Arkansas Soil and Water Conservation Commission (ASWCC), began recording the signs that the region's groundwater resources were now rapidly shrinking.
Further studies were conducted by multi-agency teams reached similar conclusions.
From these studies, the U.S. Congress in 1991 empowered the USACE to develop a Grand Prairie Area Demonstration Project (GPADP) with the help of the ASWCC, NRCS, and WRID to find and implement an effective solution to this 90-year old problem of groundwater resources depletion.
Without an adequate solution to the region's groundwater problems, studies predict the Alluvial Aquifer will be commercially useless by the year 2015.
How will it be done?
New reservoirs will be built on approximately 8,800 acres of farmland within the Grand Prairie area, doubling the current amount of usable above ground water storage. On an as-needed basis, farmers will use this water to irrigate their crops or flood their rice fields. Water that does not sink into the ground for use by the plants or evaporate will be recovered by a ditch and pipeline system and pumped back to the reservoir.
To help supplement the volume of water necessary to meet the irrigation needs of the farmers who help till more than a quarter-million acres within the region, the GPADP will construct a pumping station on the White River at DeValls Bluff. This pumping station will be capable of lifting 1,640 cubic feet per second from the river's flow during specific times of the year to help keep the on-farm reservoir network supplied.
Supplementing the seasonal irrigation needs of agriculture would greatly reduce the present demand placed on the Alluvial Aquifer. Supplemental withdrawals from the White River would only be allowed during periods when the river's water level is adequate. While the GPADP plan allows for periodic withdrawals from the White River when its flow is above minimum flow requirements, there is no detrimental change in the river's stage as a result of such withdrawals.
What will happen without the Grand Prairie Area Demonstration Project?
The impact of this situation is much more than just the expected drying of an aquifer.
Rice production is projected to decline to less than 23 percent of its current level and growers would then be forced to farm dryland soybeans, a much less profitable oilseed crop. Waterfowl hunting opportunities would suffer because migrating ducks and geese come to the area for its flooded rice fields, a primary source of winter food.
Wetlands would lose moisture due to a further decline in water tables, if nothing is done to stop the drying of the Alluvial Aquifer. The only groundwater source remaining would be the deeper Sparta Aquifer, the area's only source of high quality drinking water.
Other consequences by 2015 from not correcting the groundwater problem:
- Decrease in farm cash receipts of 47 percent or $46 million
- Decrease in irrigated cropland by 77 percent or some 187,129 acres
- Declining land values reduce individual and family net worth
- Loss of farm loans due to the greater financial risk associated with the inability to irrigate
- Higher exposure to catastrophic drought due to lack of groundwater for crop irrigation
- Fewer wintering waterfowl in the area due to reduction in rice acreage and a primary food source
- Decreased farmland values reduce the areas' tax base
- Further reduction in local economic synergies through:
- Closing of agribusiness processing centers
- Loss of jobs
- Loss of agricultural support businesses such as equipment sales and repair
- Competition for shallow groundwater may drive agribusiness to the only remaining commercial source of water in the area, the deeper Sparta Aquifer which contains the area's only reliable source of drinking water
- The desiccation of wetlands along the White River
The Grand Prairie region's future existence, including agribusiness and recreation - combined to produce essentially the same economic synergies it has today plus a potential for growth - depends largely on the construction and completion of GPADP.