With the concrete towers of Hoover Dam in the background and the depleted waters of the nation’s largest reservoir below, an unlikely group of allies — conservation activists, businesspeople and officials representing cities and farming communities — on Thursday called for halting all plans that would take more water from the shrinking Colorado River.

The 10 people who spoke at the news conference said they’re part of a new coalition demanding a moratorium on new dams and proposed pipelines, including a proposal to transport Colorado River water to sustain urban growth in Utah.