A federal judge in Nebraska dismissed a lawsuit on Tuesday that challenged a state-approved plan to pump groundwater into surface-water streams that feed the Republican River.

U.S. District Judge Joseph F. Bataillon ruled that the federal government was immune from the lawsuit and declared the case a state matter in which he shouldn't intervene.

The lawsuit rises from a water dispute that has pitted two Nebraska irrigation districts against state and federal officials. In October, the Nebraska Department of Natural Resources and four other natural resources districts announced an $83 million purchase of Lincoln County farmland from a Delaware investment group.

Buying the land would allow them to take nearly 15,900 irrigated acres out of production, so they could pump the water beneath it into a Republican River tributary.

The plan was designed to help Nebraska meet its obligations to Kansas under the Republican River Compact, a water-sharing agreement between those states and Colorado. The 1943 river compact allocates 49 percent of the river's water to Nebraska, 40 percent to Kansas and 11 percent to Colorado. Nebraska has faced lawsuits from Kansas in recent years for allegedly overusing its supply.

The lawsuit was filed by the Frenchman Cambridge and Bostwick irrigation districts in south-central Nebraska, and three farmers who use water within the districts.

They argued that the $2.1 million pipeline project would deprive streams, rivers and federal lakes of water to which they are entitled. They also asserted in the lawsuit that the Upper Republican River was overusing its supply, and accused the federal government of failing to protect their legal rights to the water.

Construction is set to begin on a 4.5-mile pipeline to ship the groundwater.

Brad Edgerton, the manager of the Frenchman Cambridge Irrigation district, said he was aware of the ruling but had not yet reviewed it in detail. He said it was too early to know whether the districts and farmers would file an appeal. Edgerton has said his district's surface-water rights were violated because of over-development of groundwater irrigation. The increase in groundwater wells has reduced river flows that are used to deliver water to customers within the irrigation district, he said.

The lawsuit was filed against Gov. Dave Heineman, Department of Natural Resources director Brian Dunnigan, the Upper Republican Natural Resources District, and N-CORPE, the group that was formed for the pipeline project. It also named the United States government, Secretary of Interior Ken Salazar, Bureau of Reclamation Commissioner Michael Connor, and the agency's Great Plains region director Michael Ryan as defendants.

Jasper Fanning, manager of the Upper Republican River Natural Resources District, said the groups are planning to move forward with the water-augmentation project.

"We're obviously pleased that the case was dismissed," Fanning said.