City of Thornton v. City of Fort Collins

The Cache La Poudre River (Poudre River) flowed through the City of Fort Collins (plaintiff). The Poudre River eventually joined the South Platte River, which was a primary water source for the City of Thornton (defendant). Fort Collins had two dams located on the Poudre River, the nature dam and the power dam. The nature dam was built to divert the Poudre River back into its historic channel after heavy rains had altered the river’s course. The power dam was recently renovated with the addition of a boat chute for recreational use and a fish ladder for fish-preservation purposes. The boat chute and fish ladder were both functional. Fort Collins applied to the water court for a conditional surface water right to use a certain amount of water for municipal purposes in its Poudre River Recreation Corridor. Thornton filed a statement of opposition against Fort Collins’s application. The Colorado Water Conservation Board (the board) and state engineer also filed objections. After negotiating with the board and the engineer, Fort Collins amended its application to remove the corridor as the diversionary structure on which the application was based. The two dams were substituted in the amended application as the diversionary structures for which water rights were sought. The water court determined that the nature dam was a diversion and granted Fort Collins a conditional water right for the nature dam. However, the water court found that the power dam was not a diversion and denied a conditional water right for the power dam. Thornton appealed the grant of a water right to Fort Collins for the nature dam. Fort Collins cross-appealed the denial of a water right for the power dam.