Amends the Irrigation Project Contract Extension Act of 1998 to: (1) extend each of the water service or repayment contracts for the Glendo Unit of the Missouri River Basin Project identified under the Act until December 31, 2005; (2) extend the Cooperative Agreement for Platte River Research and other Efforts Relating to Endangered Species Habitats Along the Central Platte River, Nebraska, for a term beyond December 31, 2005; and (3) require, if such cooperative agreement terminates before such date, the contracts to be subject to renewal on the termination date.