Portland Water Bureau Starts Maintenance Operation

The Portland Water Bureau begins its annual maintenance operation Monday - switching from 100 percent water from the Bull Run Watershed to a blend with water from the Columbia South Shore Well Field.

The bureau points out that while they don't have to make public notification when they make a move like that, they are aware people are very sensitive about the water supply.

The city normally gets all of its water from the Bull Run Watershed, a 102-square mile area that collects water from rain and snowmelt that flows to the Bull Run River and its tributaries.

The river drains into two reservoirs that store more than 17 billion gallons. The water is then treated before it travels - by gravity - to Portland.

Every so often, the water bureau conducts maintenance during which they blend groundwater from the Columbia South Shore Well Field with water from Bull Run.

The operation is expected to last about 10 days.