Water diversion gates on the Sacramento River near Walnut Grove were reopened Thursday after repairs.
The Delta Cross Channel Gates, owned by the U.S. Bureau of Reclamation, became stuck open May 29 because of a mechanical failure.
The gates, built in the 1950s, divert a portion of the river into the interior Delta, then to diversion pumps near Tracy.
During spring, the gates are closed weekdays to help young salmon migrate to the ocean, and opened on weekends for boat traffic.
The failure presented a concern that more migrating salmon would stray through the gates and lose their way or become vulnerable to predators.
Officials said the risks were small, as most salmon migration had already occurred.
Engineers figured out how to close the gates June 4.
Repairs continued until Thursday, when the gates were reopened at 1 p.m.
The gates are expected to remain open to boaters until further notice, as the salmon migration period has ended.
For more information and to check the current status of the gates, go to www.usbr.gov/mp/cvo.