While the exact details are still to be determined, this diagram has two likely locations at: approximate coordinates: -122.69830, 45.47797)
The lower/South box is the preferred location, with the upper/North box as an alternate, but a challenge due to the slope and vehicle access pressures.
Water lines run through the outer edges and the container cannot be closer than 5' to them. It also may not be placed under the Capitol Hill Road bridge.