Reservoir 4 Gets its Twice-Yearly Bath

Operating Engineers from the Water Bureau drained and cleaned Reservoir 4 in Washington Park last week. Here are some photos of the debris they found during the cleaning, including chunks of the reservoir (it's 112 years old this year!), batteries, plastic, and tree limbs. Reservoir 4 holds 17.6 million gallons of water when full. 

The open reservoirs range from 100 to 117 years old. While they may look fine when full, they are in poor condition. The concrete is deteriorated, with cracks and chunks missing, the lining panels have eroded, and the steel pipes and valves are corroding. 

In 2006 the Environmental Protection Agency ruled that water utilities discontinue the use of open finished water reservoirs. The three Mount Tabor Reservoirs will be disconnected from the City's water system by 2015; the Washington Park Reservoirs disconnected by 2020.

In the meantime, each reservoir will continue to be cleaned twice yearly, and also when vandalism necessitates it, as this story illustrates: paint prank wastes 40-million gallons of city drinking water.

Click here for answers to Frequently Asked Questions about Portland's Open Reservoirs.

- Sarah Bott