Survey shows aquifer levels still dropping, but a wetter 2015 helped

Mar 15, 2016

Credit Kansas Geological Survey / Kansas Agland

From Kansas Agland:

It has become known as the miracle May.

The spring was dry. Farmers were thinking it could be another drought disaster year. And then May came. The skies opened and anywhere between 6 and 12 inches fell in many areas of the state.

The momentum continued for a few months – the heart of the Kansas growing season – and long enough for irrigators to turn on their irrigation wells later and not pump as much from Kansas’ declining aquifers as past years.

The annual water-well survey by the Kansas Geological Survey shows the state’s aquifers are still dropping. However, declines are at a much slower rate thanks to a wetter-than-normal 2015 and the miracle in May.

“It shows that rainfall can make a lot of difference and increased rainfall relates directly to reduced pumping,” said Stevens County farmer and irrigator Kirk Heger.

He estimated his region of the state might have seen up to a 20 to 25 percent decrease in irrigation pumping in 2015.

Yet, despite rainfall, the urgency of the situation isn’t lessening for western Kansas, where irrigators and others pump water out of the ground faster than precipitation can recharge it. Groundwater levels in southwest Kansas, where the Ogallala Aquifer is the richest, have fallen more than 38 feet since 1996, when the state began monitoring wells.

The issue is at the forefront for Gov. Sam Brownback and his staff, all of whom have been tackling Kansas’ water woes during Brownback’s tenure in office. That includes implementing a water vision for the state two years ago – which includes stringent goals with targets in an effort to preserve and extend the state’s water resources.

Brownback has said that if Kansans continue down the current path, the state’s water resources could be nearly spent in 50 years and roughly 70 percent of western Kansas’ Ogallala Aquifer would be depleted by 2064.

Some farmers have said the issue is even more dire than the state’s figures and these figures could be reached even faster if irrigation pumping isn’t curtailed in some way.

Credit National Weather Service

Slower declines

The vast majority of groundwater pumped in western and central Kansas is drawn from the High Plains Aquifer, a massive underground network of water-bearing rocks that underlies parts of eight states.

In Kansas, it comprises the far-ranging Ogallala Aquifer as well as the smaller Equus Beds around Wichita and Hutchinson, along with the Great Bend Prairie Aquifer that covers Great Bend, Kinsley, Greensburg and Pratt.

The Kansas Geological Survey measures groundwater levels in about 1,400 High Plains Aquifer water wells every January as part of an annual program monitoring the state’s finite resource.

The rain last year not only was a drought buster, but also helped irrigators cut back on pumping, said Brownie Wilson, the survey’s water-data manager.

Wilson said Thursday the water levels fell only slightly across western Kansas’ Ogallala Aquifer – the lowest in five years. He noted Kansas had been in a multiyear drought since 2010 and the drought-busting precipitation helped slow the depletion rate of groundwater because less irrigation – the region’s primary use of the groundwater – was required.

Liberal, for instance, received more than 12 inches of rain in May and had a record 49 inches for the year.

Typically this semi-arid region receives just an average 20 inches a year.

Dodge City received 28.32 inches of rain in 2015, about 8 inches over the tabulated annual average rainfall. Most of the rain came in May – 10.33 inches.

Wilson said southwest and west-central Kansas received 150 to 200 percent of normal annual precipitation.

“Above-normal precipitation levels in May and July during the growing season, and in some places again in August, really helped to ease pumping demands, which led to an overall reduction in water-level declines,” Wilson said.

“Western and southwestern Kansas – they saw tremendous amounts of rainfall – even double what they normally get,” he added.

An irrigation system spreads water on a cornfield west of Hutchinson in 2012.
Credit Lindsey Bauman / Hutchinson News

Well survey

Wilson said as a whole, the state’s 1,400-well network declined an average 0.37 feet – the smallest decline since 2009. Amid the drought – from 2010 to 2014 – levels fell a total of 7.21 feet.

In west-central Kansas’ GMD No. 1, which spans from Wallace and Greeley to Lane County, water levels dropped 0.04 feet. During the previous five years, the table averaged a five-foot decline.

Meanwhile, northwest Kansas had a decline of 0.58 feet. Big Bend GMD 2, which covers parts of Barton, Pawnee, Edwards, Kiowa, Reno and Rice counties, fell 0.38 feet.

Much of central Kansas also experienced small declines, although levels rose substantially around Wichita.

Equus Bed GMD 2 is a major source of water for Wichita, Hutchinson and surrounding towns. Wilson said the eastern half of the district saw 3- to 6-foot rises. However, the western part of the district saw declines of up to a foot.

Still, he said, GMD 2’s average water level rose 1.45 feet in 2015. In 10 of the past 20 years the average level rose, keeping the long-term water level of the Equus Beds relatively steady.

Those differences in water level measurements coincided with precipitation patterns, Wilson said. Rice and Reno counties to the west experienced normal or slightly-below-normal precipitation, while Harvey and Sedgwick had above-normal precipitation.

In southwest Kansas – the heart of the Ogallala Aquifer – declines across Groundwater Management District No. 3 averaged 0.84 feet. That’s a big improvement from the past five years, when water levels dropped 15 feet, Wilson said.

Since 1996, southwest Kansas water levels have dropped an average 38 feet, according to the geological service.

Water vision

That’s why irrigators continue to look for ways to preserve the Ogallala, said Heger, who serves on the newly formed regional basin advisory team for his area. The basin teams are part of the year-one goals in Brownback’s water vision plan.

Mark Rude, executive director of Southwest Kansas’ GMD 3, said irrigators still use a lot of water, but the rainfall was a blessing that helped irrigators cut back on usage.

“There was a lot to be thankful for last year,” he said, adding that the rain produced bumper crops, including milo. “It was a wonderful miracle May.”