After a protracted environmental battle, Moran Dam was defeated in 1972, mainly over concerns of its adverse impact on salmon populations in the Fraser River basin.

The shelving of the project also influenced cancellation of other hydro developments along the river, and today the Fraser remains one of the most productive salmon fisheries on the continent.

[6] During the later 1950s and 1960s, determined opposition from environmentalists including Roderick Haig-Brown,[17] fishermen and others stalled the project, citing that the dam would block access to over 70% of anadromous fish spawning habitat in the Fraser basin.

In addition, it would cause losses of up to 50% of catches along the main stem Fraser and its delta below the dam because of sediment blockage, water temperature changes, and flow fluctuations.

As a result, the proposed dam project was briefly revived, to the point at which test bores were made at the site in May of that year.