Midway Sewer District Submarine Outfall - Kent, Wash.
The initial 285 ft of pipe was installed through a jacked and bored casing installed by a subcontractor. This runs from the Des Moines Beach Park, under a hill, and out the upper portion of the beach. The next 600 ft were installed at low tides with an excavator in a sheet pile trench. All work was performed on non-floatable mats to protect the beach. The next 400 ft of pipe going offshore was installed by divers and a derrick barge in an excavated trench with sheet pile to protect the eel grass. Past the sheet pile, the pipe continues in an excavated trench for 200 ft then daylights and was set on the bottom out to the station 21+00. Precast anchors were set over the unburied section of pipe.