K-State Research and Extension News
May 19, 2014
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Water Quality Gets Big Improvement in Little Arkansas River Watershed

https://creativecommons.org/licenses/by-nc-sa/2.0/Working together to restore and protect surface waters and reduce water treatment costs

MANHATTAN, Kan. -- Located in central Kansas, the Little Arkansas River watershed is one of the most intensive agricultural watersheds in the state, with 97 percent of its land area in agricultural production.

Many of these acres are used for either corn or grain sorghum production and a majority of producers in the watershed use atrazine herbicide for control of broadleaf weeds and grasses.

Kansas State University studies have shown atrazine to be one of the most effective and economical soil-applied herbicides for season-long weed control. But research also has shown that because atrazine is water soluble, atrazine can run off fields during rainfall, sometimes creating a surface water quality issue in the Little Arkansas River watershed and other heavily farmed watersheds.

Spring and early summer are periods of heavy atrazine application due to corn and sorghum planting, resulting in the concentration of atrazine in the surface waters during this season to sometimes rise above the drinking water maximum contaminant level and the aquatic life standards for atrazine set by the Environmental Protection Agency.

Little Arkansas River extension watershed specialist, Ron Graber explains that Wichita has an aquifer re-charge project where they are attempting to capture water during high flow conditions of the Little Arkansas river and then inject it back into the groundwater aquifer for later use. 

Before it can be injected, the water must meet drinking water standards, however most municipal water treatment plants do not remove atrazine and other pesticides because it requires an activated carbon treatment system to the treatment process, which increases the cost of the facility and the day-to-day cost of water treatment.

“The Little Ark Watershed is currently the only one focusing on this in Kansas,” Graber said.  “Other parts of the state may not be aware of some of the issues with atrazine, but in our area it’s a pretty heightened responsiveness because of the city of Wichita.”

Incentive for Change

In 2004, a local group of watershed stakeholders developed a plan to restore and protect the surface waters of the Little Arkansas River watershed.  The main goal of their Watershed Restoration and Protection Strategy (WRAPS) is to encourage farmers to minimize atrazine loss from crop fields, thereby reducing atrazine runoff to surface waters to levels that meet water quality standards.

“We knew we couldn’t totally eliminate atrazine runoff,” Graber said “but if we could keep it at a minimum and prevent the spikes in atrazine concentration then that’s a tremendous benefit to the city of Wichita in terms of the amount of money they spend treating the water.”

Their approach uses the best management practices developed to minimize atrazine runoff and established a cafeteria-style incentive program for producers to select the practices that fit best to their unique operation.

“It’s not the sort of thing where you say in this field you can’t use atrazine,” Graber said “but more of here’s some things that you can do to help reduce runoff, will one or two of these practices fit into your scheme?”

Graber said that the flexibility offered by the program is a crucial part of their success and sets them apart from traditional farm programs.

By using a dollar-per-acre figure, producers know right up front that what they do will dictate the amount of incentive they receive. Producers who stop using atrazine will get the full amount of incentive while other producers who choose a practice that is predicted to result in a 50 percent reduction of atrazine runoff will receive 50 percent of the incentive dollars available per acre. 

Little Ark, Big Impact

Over the past 10 years, Graber and other members of the WRAPS team have made extensive education efforts to reach out to local producers in terms of meetings, letters, one-on-one consultations, farm visits and newsletters.

“In the first few years we learned pretty quickly that crop consultants and chemical dealers were key to the success of the project,” Graber said.  “We met with those in our area to make sure they know what results we were seeing.  We could tell the producer one thing, but if the people they buy their chemical from and the consulting services they hire tell them to do something different, it’s not hard to guess which one they will listen to.”

When the incentive program first started in 2006 they had 41 farmers in the program and they implemented best management practices on 4,792 acres of land in committed watersheds and saw 18 percent less atrazine used.  In 2013 the program included 103 farmers, 19,544 acres of land with implemented best management practices and saw a 52 percent decrease in the amount of atrazine used.

Water samples taken from a paired watershed monitoring system in the targeted areas have shown dramatic improvements in the amount of atrazine concentration levels in surface water, with the improvement in some years being as high as 60 percent.

“I’d like to think of it as we’re helping them change the way they do things,” Graber said. “We’ve been doing it long enough that we are seeing some producers using these practices without any incentives.”

The city of Wichita has been happy with the participation rate and the reduced levels of atrazine found in streams and rivers in the area. In 2006, the WRAPS team approached the city of Wichita to ask for financial support and received $10,000, which was matched by another source.  The city’s financial donation has grown to $50,000 for incentives as well as providing all the water analysis needed, representing an estimated total contribution of $75,000 per year.

For more information about the Little Arkansas River watershed and the work they have done to protect their surface water and help producers manage atrazine effectively visit the K-State Research and Extension publication MF-2768, “Atrazine Herbicide Best Management Practices for the Little Arkansas River Watershed” located online.


K-State Research and Extension is a short name for the Kansas State University Agricultural Experiment Station and Cooperative Extension Service, a program designed to generate and distribute useful knowledge for the well-being of Kansans. Supported by county, state, federal and private funds, the program has county Extension offices, experiment fields, area Extension offices and regional research centers statewide. Its headquarters is on the K-State campus, Manhattan.

Story by: Kaitlin Morgan
K-State Research & Extension News

Ron Graber – rgraber@k-state.edu