In the case of Portneuf-Marsh Valley Canal Company v. Brown et al., Trustee, 1926, the U.S Supreme Court was asked to decide on a dispute over water rights in Idaho. The Portneuf-Marsh Valley Canal Company had been granted rights by the state to divert water from certain streams for irrigation purposes but later found that there wasn't enough water available during dry periods. As such, they constructed reservoirs and stored surplus waters from wet seasons for use during drier times. However, this action was challenged by downstream users who claimed it violated their own vested rights to continuous flow of these streams as per state law. The court ruled in favor of the canal company stating that under Idaho law at that time (prior to 1903), appropriators could store excess or floodwaters without infringing upon other users' existing rights provided those were not affected adversely. It further clarified that while subsequent changes in state laws did require consent from all parties involved before storage could be undertaken; these changes didn't apply retroactively and hence couldn’t affect previously established legal storages like those made by Portneuf-Marsh Valley Canal Company.

In the dissenting opinion for Portneuf-Marsh Valley Canal Company v. Brown et al., Trustee, it was argued that the majority's decision to uphold a lower court ruling favoring Brown and his fellow trustees was incorrect. The dissenters believed that the canal company had not violated any rights of the plaintiffs by using water from Marsh Creek for its operations because it had been granted this right by Idaho state law. They also disagreed with the majority's interpretation of "beneficial use" in relation to water rights, arguing that beneficial use should be determined based on whether or not an entity is making productive use of water resources rather than who has prior claim over them. Furthermore, they contended that even if there were some infringement upon plaintiff’s rights, such harm would be minimal and thus insufficient grounds for granting an injunction against defendant’s activities.