When we started irrigating the High Plains in the 1950s, the Ogallala was understood to be that vast, virtually endless supply of water. When the water table dropped, we thought the groundwater could flow unimpeded from one area to another. But the groundwater of the Ogallala aquifer really doesn’t flow laterally with much speed. Playa lakes provide areas of focused recharge to the aquifer, and improve the quality of that water. The result is high quality water reaching the aquifer that can be used by you, your children and future generations.
This is Playa Country — a weekly look at the wildlife, wetlands and prairies of the western Great Plains, and the people who manage them — brought to you by Playa Lakes Joint Venture, an organization dedicated to conserving birds and bird habitat.
When I was a kid in the ’60s, helping my dad on his farm south of Dodge City, he’d talk about the aquifer our old windmills were pumping water from out in the pasture. He always described the Ogallala as an underground river. That understanding of the aquifer implied that groundwater was free to flow, just like a surface river. In the 50 years since then, scientists have learned lots about underground structures that are permeable to water flow. In some aquifers water is able to freely migrate from one area to another, but not so much when we talk about the Ogallala. Ken Rainwater is a water resources engineer at Texas Tech. Ken studies groundwater.
“Regionally, here in the Southern High Plains of Texas, we talk about the velocity that the groundwater might move through the aquifer on its own on the order of a few feet per day, maybe a few hundred feet per year, depending on where you are.”
So the groundwater of the Ogallala aquifer really doesn’t flow laterally with much speed. Randy Stotler’s a hydrogeologist at University of Kansas. He studies western Kansas playas.
“Some of the work that I’ve been doing with the Kansas Geological Survey, we’ve come to realize that there are quite a few parts of the High Plains Aquifer that are actually more compartments, or kind of individual bathtubs, rather than one big river.”
Stotler describes the makeup of the aquifer as not so much a river, but more a series of adjacent ‘bathtubs’ which tend to compartmentalize the effects irrigation wells have on their neighbors. Stotler says the compartmentalization of water becomes more significant as water levels decline.
“Where as one single irrigation well may have connected into a whole bunch of different bathtubs that might be of different sizes, they might reach over to a neighbor’s property. In fact, what we are starting to see is these compartments are becoming more individualized.”
One of Randy’s sites in southwest Kansas demonstrates this process.
“There’s one guy that can turn on his irrigation well — and we have an abandoned well about 60 feet away or so — and we see absolutely no response in that well. But, he might turn on a well and somebody two miles away, we can see the response in that well in the water levels.”
Stotler has learned the lower the water table dips, the more localized are the effects of pumping groundwater. Playa lakes provide areas of focused recharge to the aquifer, with rates in playa basins 10 to 100 times higher than other areas. That highlights the importance of having high-functioning playa lakes — playas that haven’t been pitted, playas that aren’t silted-in, and playas with a perimeter plant buffer.
Healthy playas provide benefits beyond the amount of aquifer recharge. Water reaching the aquifer through playas is cleaner than water that enters through upland soils and other channels. The result is high quality water reaching the aquifer that can be used by you, your children and future generations. There’s also the satisfaction of providing local and migrating birds and other critters habitat that helps them thrive.
When we started irrigating the High Plains in the 1950s, the Ogallala was understood to be that vast, virtually endless supply of water. When the water table dropped, we thought the groundwater could flow unimpeded from one area to another. That led to a mentality of ‘If I don’t pump it, the fellow down the road will.’ This new information about the Ogallala is likely to change people’s mentality when they understand that the way you treat your piece of the aquifer, under your property, will affect the amount and quality of your groundwater for future generations.
This episode of Playa Country was made possible by Playa Lakes Joint Venture, and a grant from the Wildlife Conservation Society, with support provided by the Doris Duke Charitable Foundation.
Original broadcast: August 2016