State Plan: Divert Surface Water To Make Up For Groundwater Loss
Between $3.4 billion and $7.8 billion should be invested in the infrastructure needed to help Arkansas take advantage of surface water instead of unsustainably pumping from depleting groundwater sources. The good news: The state has more than enough surface water to take care of its needs.
Those are some of the conclusions of the Arkansas Water Plan 2014 Update, a non-binding strategic plan that guides the regulatory and legislative priorities of the Arkansas Natural Resources Commission. The plan, first published in 1975, was last updated in 1990, and the current update began in 2011. The commission will vote on whether or not to accept the 2,622-page update Tuesday.
According to the plan, Arkansans will use 11 billion gallons of water today. In a year’s time, that’s 12.4 million acre-feet – enough to cover the entire state in 4.2 inches of water.
Ed Swaim, Arkansas Natural Resources Commission water resources division manager, told the American Council of Engineering Companies of Arkansas Friday that, by 2050, that number rises to 14 million acre-feet per year, which raises the water level to 4.9 inches.
About 71 percent of state needs are supplied by pumping groundwater. Demand for groundwater is already 8.7 million acre-feet per year and is expected to grow, while groundwater can supply only 1.9 million acre-feet per year at a sustainable pumping rate. Arkansas County has already bottomed out in places and is using surface water. Mississippi County will lose maybe 40-50 feet of its water table in the coming years, Swaim said.
"The folks with the superabundant groundwater, they don’t like to acknowledge it, but their day is coming. They’re going to see these declines," Swaim said.
80 percent of all water use in Arkansas goes to crop irrigation, followed by thermoelectric power, which uses 11 percent, and public drinking water, which uses 3.5 percent. Industrial demand currently is 291 million gallons a day and is decreasing. The state averages 259.2 million gallons a day for flooding fields to hunt ducks – almost as much as it uses for manufacturing, Swaim said.
As a result, rapid depletion is occurring in the Grand Prairie’s alluvial aquifer, the Sparta Aquifer in south Arkansas, and areas east of Crowley’s Ridge where the Mississippi River doesn’t penetrate the clay soil.
Groundwater conservation efforts could reduce the supply gap by 12 to 22 percent – not nearly enough to solve the problem. But Arkansas has abundant surface water through a network of rivers and lakes along with rainfall totaling four or five feet per year, Swaim said.
Gaged streamflow in the state is 92.5 million acre-feet per year, of which only 57.5 million acre-feet is needed to maintain current needs for transport, fish and wildlife, and maintaining the flow into neighboring states. And that’s not counting the Mississippi River, which was left out of the report because it borders other states. Of the rest, a quarter can be diverted under current state law. That would provide about 8.6 million acre-feet per year – about the same as the current groundwater deficit. More would be available by changing the law.
The cost of diverting enough surface water to meet Arkansas’ needs is between $3.4 billion and $7.8 billion. Pumping surface water horizontally will be cheaper for farmers than pumping groundwater vertically, Swaim said. Arkansas’ annual agricultural production has a $9.7 billion market value, according to the plan.
"This is where we believe that we’ll meet our future needs," Swaim said. "And if we do it, and it will cost about as much as those improvements to water and sewer projects, to build the infrastructure and move this water primarily in east Arkansas, we will not have a shortage of water to do everything we need to do, and we will not have harmed any other use of water."
The draft plan recommends that the Arkansas Natural Resources Commission have the authority to force the merger of small water and sewer systems that cannot meet their financial obligations on their own. It also calls on the commission to encourage more voluntary sustainability planning by water system boards.
A potential area of disagreement is a proposal to ask the Legislature to require all farmers applying poultry litter or animal-based fertilizer to have a nutrient management plan. Currently only farmers in Northwest Arkansas are required to have a plan, Swaim said in an interview after his presentation.