Photo: Shannon Mullane/The Colorado Sun

DURANGO — Over two days of hearings, Colorado water managers laid out their arguments related to one of the most powerful water rights on the Colorado River and who should have the authority to control it.

The Colorado River Water Conservation District plans to buy the water rights associated with the Shoshone hydropower plant in Glenwood Canyon from Xcel Energy and use the water for environmental purposes. To do so, it must secure the support of the Colorado Water Conservation Board. The CWCB is the only entity allowed to own instream-flow water rights, which are designed to keep a minimum amount of water in rivers to benefit the environment.

The CWCB heard more than 14 hours of testimony Wednesday and Thursday from the River District and its supporters, as well as the four big Front Range water providers — Northern Water, Denver Water, Aurora Water and Colorado Springs Utilities. All the parties agree that the water rights would benefit the environment.

But the Front Range parties object to certain aspects of the River District’s proposal that they say could harm their interests. They said this is not a water grab for more; their goal is to protect what they already have.