The emergence last summer of blue-green algae in the Kansas River still has Lawrence raising a few red flags about the effect the toxin has on the city’s drinking-water supply.

City officials now are hoping that a special study by the U.S. Geological Survey will shed light on the severity of last summer’s algae outbreak and give water plan operators a better idea of what to expect in the future.

“I don’t think anyone expects this to be a one-time occurrence,” said Mike Lawless, an assistant director of the city’s Utilities Department. “I think there will be some long-term issues that we’re going to have to look at as a result of this.”

City commissioners at their meeting Tuesday agreed to pay nearly $20,000 for the city’s share of a $136,000 study of the Kaw River algae outbreak that began last August when water from Milford Lake was released. Also sharing in the cost will be the city of Topeka, Johnson County-based WaterOne, the Kansas Water Office, the Kansas Department of Health and Environment, and the USGS.

The USGS took samples of the Kansas River during the outbreak and now will provide an analysis of what led to the outbreak and what effect it had on the river and one water system that rely on the river for public drinking water.

Lawrence City Hall officials briefly shut down the Kaw River Water Treatment Plant during the algae event while it tested to ensure that none of the blue-green algae was showing up in the treated drinking water. The tests ultimately did not detect any blue-green algae in the treated water.

But the city wants to learn more about how much blue-green algae was in the untreated water that the plant was taking from the Kaw. The issue of blue-green algae has not been extensively studied by the water treatment industry. The Environmental Protection Agency does not have any standards related to blue-green algae in public water supplies. But health officials agree that too much exposure to blue-green algae toxins can cause health problems in humans and especially pets.

“I expect this study probably will lead us to do other studies down the line,” Lawless said.

The USGS likely will finalize its report by April, Lawless said.