PENINSULA DRAINAGE DISTRICT NO. 1
Peninsula Drainage District No. 1 is located in Multnomah County, along the south bank of the Columbia River between river miles 105.6 and 106.5. The district is bounded by Lower Columbia Slough on the South, and the embankments of the Union Pacific Railroad and Burlington Northern Railroad, on the west and I-5 Interstate Hwy on the east. The drainage district includes 901 acres, of which 125 acres are utilized for industries. The City of Portland Park Bureau has Portland International Raceway, Heron Lakes Golf Course, Metro’s Expo Center, Industry along NE Marine, Port of Portland Vanport Wetlands and Ross Island Sand and Gravel Company. Land elevations range between 6.0’ to 25’ NGVD 29.
1919 - 1921, initial construction 4.9 miles of levee began and the addition of a pumping plant.
1940 – 1941, a new pump plant was constructed, stop log closures (Flood Wall) along N. Portland Harbor were constructed and 2 – 20” vert. pumps were installed. In addition, drainage canals were dug to carry runoff water to the pumps.
1948, general repairs of the levee system were accomplished including, installation of a sand filter and drain tile and cleaning out drains, sewer outlets, culverts and ditches.1956, the Corps closed an existing culvert with a sheet pile cut-off-wall.
1960, rock bank protection was placed along 4,178 linear feet of levee.
1972, operation foresight (flood prevention measure) was put into operation, which involved placement of sand reinforcement along the railroad embankment, and plug in Lower Columbia Slough, and to deepen the trench inside of the railroad embankment.
1992, stop logs were designed to be placed at the two under crossings of the Burlington Railroad on the west border of the district.
1996, the drainage ditch north of the pumping plant in PIR was piped with a 60” cmp and filled to grade to prevent slope failure during the 1996 high water event.
1997, the Army Corps of Engineers reconstructed the discharge piping from the PIR pumping plant.
1998, the district rebuilt the pile supports and upgrade electrical and increased pumping capacity from 12,000 gpm to 20,000 gpm at the PIR pumping plant.
1999, because of the unreliability of railroad construction techniques and the fact the railroad embankment failed in 1948 and the high water seepage during the 1996 support the belief the railroad embankment contains construction debris and pervious gravel zones. The Army Corps of Engineers reinforced the landward slope of the railroad embankment with a sand and soil blanket to meet Federal levee design standards.
2001, 8 stormwater pipes penetrating the Columbia River levee were retrofitted with tide and slide gates.
2005, the 24” cmp discharging from Graphic Packaging was sleeved with ADS and retrofitted with a tide gate.
2007, PD1 contracted with the Army Corps of Engineers to recertify the levees and pumping plants for FEMA’s FIRM program. Certification approved by FEMA.
Top Elevation of the levees (in feet NGVD 29)
East End - 35.3'
West End - 35.3'
Prelim. Peak Fld. El (in feed NGVD 29) at the Midpoint of Levee
| 10-yr|| 50-yr||100-yr || 500-yr||Levee Design Flood |
| 21.4'|| 25.5'|| 27.2'|| 32.0'|| 32.0'|
Levee Freeboard (in feet NGVD 29)
Levee Design Flood - 3.3
100-year - 8.1
Safe Water Level (in feet NGVD 29) 22.0’
*This elevation taken from NPP Publication; Drainage district condition study on Safe Water Surfaces Levels, May 1978.