Northern California and Oregon irrigation districts have won a key round in a long-running legal battle as they seek compensation for their loss of water in the Klamath River Basin. In a 53-page opinion, U.S. Court of Federal Claims Judge Marilyn Blank Horn concluded the federal government’s 2001 diversion of Klamath River Basin water amounted to a “physical taking” of the irrigation districts’ property. Horn’s ruling Wednesday rejected the government’s argument that the diversion instead amounted to a “regulatory taking.”