An estimated 3,400 gallons of raw sewage spilled into a dry ravine in Wahiawā yesterday, the city said.

Tree roots clogged a 6-inch siphon pipe, causing a manhole fronting 77 Karsten Drive to overflow.

Crews from the city Department of Environmental Services secured the site at 7:30 p.m.

There is no public access to the area, and the wastewater should not reach the Wahiawā Reservoir, the city said.