Northeast of Enumclaw, water managers have started the annual exercise of slowly filling the reservoir at Howard Hanson Dam at the headwaters of the Green River.

As is typical, the Army Corps of Engineers started filling the reservoir in late February.

The process takes roughly three months to refill the reservoir. The current plan targets a maximum pool elevation of 1,167 feet above sea level. That has been the spring refill target since 2007.

Water stored during the spring refill is used to provide water supply to the city of Tacoma and its water supply partners. Additionally, at least three-fifths of the reservoir’s supply will be used to augment downstream flows to help endangered species of fish, including Chinook and steelhead. Project managers believe the regulated downstream flows will aid spawning and other life-cycle events for the fish.