The Arizona Public Services company (APS) has decommissioned its Childs and Irving hydroelectric power plants on Fossil creek in Arizona, US, to restore full flow to the river. Both structures will eventually be removed.

In a creek-side ceremony, the two plants, located in a remote area between Strawberry and Camp Verde 193km north of Phoenix, ceased operation after providing power to Arizona for almost 100 years. Full flow of 1.22m3/sec has now been restored to 22.5km of stream.

APS has worked with the US Fish and Wildlife Service and many other partners in a project to return the creek to its natural condition, and create an ecosystem that will encourage the development of several species of native fish, such as the longfin minnow, the speckled dace and the humpback chub.

Over a ten-year period, the dams will be almost entirely dismantled, at a cost of around US$17M. The plants produced a combined output of 7MW – less than 1% of APS’ total power supply.

APS president and CEO Jack Davis said that removing the dams and returning the stream to its full flow was the best option for Arizona. The decision has met with the approval of environmental groups, such as the Center for Biological Diversity and the Arizona Game and Fish Department.

The Childs and Irving plants were built in 1909 and 1916 respectively. Although removal is planned, the power house and icehouse at the Childs site will remain as historic artefacts.