Much of Portland’s urban water supply is stored on top of an extinct volcano within the city, called Mt. Tabor. In a synchronized set of actions, each of the three open reservoirs are alternately drained and scrubbed clean twice a year. Large volumes of water are shifted around to allow for the entirety of their surfaces to be meticulously power washed.
The park that contains the reservoirs attracts a wide set of gravity-fed uses, both in the planned infrastructure and in the spontaneously co-opted, such as the built-it-yourself soap box derby races that thread their way between the ponds every summer.
While the reservoirs are empty, their scale and depth are revealed, particularly with people within them. Sort of like a large velodrome; the bathtub rings appearing like wear patterns. Or perhaps the concave basin is more like a constructed cinder cone that references the geology into which it was inversely poured.
The reservoirs are also contested territory. The city of Portland has battled with the EPA over the past couple of years in an effort to keep the reservoirs uncovered – a rarity for urban drinking water these days. When the reservoirs are full, there is something remarkable in being able to visually connect with all this mountain harvested water that you and everyone else in town is going to be imbibing after it makes its way through a gridded maze of gravity fed pipes to re-emerge somewhere down below.