by: Sam Bennett, 
The planter bed at 10th and A is an eye-grabbing way the city is using to filter stormwater.

Drivers along A Avenue are finding it hard not to stare at the unusual rock formation on 10th Street.

Is it a sculpture, perhaps a fountain or a rock wall?

It's actually a fancy way of filtering water before it drains into Oswego Lake and the Willamette River.

Rob Amsberry, the city's surface water management specialist, said the 10th and A planter bed uses soil and plantings to filter pollutants. The flat planter beds stair-step down, allowing the water to slowly filter at each step.

The planter bed also acts as an entry way or an 'entrance feature' to the First Addition neighborhood, Amsberry said.

The planter bed is part of the city's $1.58 million 10th Street Green Street and Pathway improvements project. The project stretches along 10th, on seven blocks that include the First Addition and Evergreen neighborhoods.

The project began in August and is almost finished.

Amsberry said most of the water that is cleansed by the planter boxes and swales will go into the Willamette River. A small portion will go into Oswego Lake, he said.

The pathways and planter boxes were built on the right of way - on a stretch that allowed the city plenty of room to build the project. In some cases, that meant giving up parking spaces in front of homes.

There are about 20 of the planter boxes along 10th, Amsberry said.

The plants soak up and break down pollutants in the water. In addition, the city used pervious pavement in some areas of the project - which will allow water to seep through to the soil.

The project was designed by Lango Hansen Landscape Architects.