The Nebraska Department of Natural Resources said Friday that the water was flowing out of the Harlan County Reservoir, in south-central Nebraska.
Department director Brian Dunnigan says the risk of a violation was too large for state officials to wait until later in the year. The 1943 compact is a water-sharing agreement among Colorado, Nebraska and Kansas.
Nebraska officials say Kansas recently expressed interest in having the Harlan County Reservoir retain some of the water so it could be used in future years. Nebraska officials say they were willing to do so, but only if Nebraska was held harmless for any shortfalls that occurred as a result. No agreement was reached.