Federal officials have extended five sand dredging permits from the Kansas River for one year while a thorough evaluation of potential impacts continues.

Since the extended permits — covering 10 locations — include previous conditions, three dredging locations will cease in May between Eudora and Bowersock Dam in Lawrence because of elevation drops in the riverbed that exceed more than two feet, according to a news release from the U.S. Army Corps of Engineers.

The current dredging permits, which expired at the end of 2012, authorized five companies to dredge 2.2 million tons annually from 10 sites. In seeking reauthorization of their permits, the companies had proposed an increase in the tonnage dredged to 3.2 million. The companies applying for reauthorization were Kaw Valley Companies, Holliday Sand & Gravel, Penny’s Aggregates, Master’s Dredging and Meier’s Ready Mix.

The dredging companies have hired the environmental consulting firm Habitat Architects to prepare a report, which is expected to be finished by early March, according to the Corps.

Friends of the Kaw, a conservation group that works on protecting the Kansas River, applauded the Corps’ decision to stop three dredging locations but expressed concern over allowing the seven other locations to continue operating.

“We are pleased that the Corps, due to unacceptable bed degradation is moving three of 10 dredge operations off the river,” said Laura Calwell, Kansas Riverkeeper for Friends of the Kaw. “We are also grateful that they are making such efforts to keep the public updated. Still, we think the Corps has plenty of scientific evidence to cease all dredging on the Kaw, right now.”