Multnomah County Drainage District
1880 NE Elrod Drive
Portland, OR 97211
Multnomah County Drainage District helps protect lives and property from flooding by operating and maintaining stormwater and flood management systems for nearly 13,000 acres of land along the Columbia Slough and the lower Columbia River. These systems include: 27 miles of levee, 13 pump stations, and 45 miles of ditches, sloughs, streams, and culverts.
MCDD manages three other drainage districts through an annual contract for management services: Peninsula Drainage District #1 (PEN 1), Peninsula Drainage District #2 (PEN 2), and the Sandy Drainage Improvement Company (SDIC). Through their collaboration, the Districts reduce flood risk for 40% of Port of Portland facilities, including Portland International Airport, with 12 million tons of goods moving through these facilities per year, $16 billion in annual economic activity and $5 billion in assessed property value across four cities (Portland, Gresham, Fairview and Troutdale), the Columbia South Shore Well Field the second largest source of drinking water in the state, serving 800,000 Oregonians, 10% of the total jobs in Multnomah County, the majority of those in industrial, manufacturing, and transport.
The Drainage Districts are considered special districts under Oregon statute. MCDD, PEN 1, and PEN 2 operate under ORS 547 while SDIC operates under ORS 554. Each District has a separate board and budget. Being special districts, we are not considered federal, state, or city governments. We have limited authority under these statutes, and our only funding mechanism is property assessments. We charge landowners in the Drainage Districts an assessment annually for our services, and cost share with landowners for special projects.
All four Drainage Districts were formed in 1917. At that time the land was primarily agricultural and flooded throughout the year. Landowners wanted to form the Drainage Districts to help protect the land from flooding so they could farm year round. Levees were built early on by the Drainage Districts and local interests. The 1936 Flood Control Act made the US Army Corps of Engineers (USACE) the primary federal agency responsible for flood control regulations and standards, including levee standards. After 1936, at different points in time, the USACE has built out and improved the Drainage Districts’ levee system.
The Drainage Districts have experienced three major high water events since their formation. In 1948 there was the Vanport flood, which killed 15 people and destroyed the city of Vanport in PEN 1. In 1964 the area experienced a high water event, and again in 1996. Though the levees breached in 1948, our levees have not breached in any other event.
To help recuperate from these events, the Drainage Districts participate in the USACE’s Rehabilitation and Inspection Program (RIP), which provides emergency repair funds in the event that a flood damages the levees and also obligates us to follow USACE regulations. To prove that our levee and drainage system can protect against future flood events, we also must accredit the Drainage Districts’ levee system through the Federal Emergency Management Agency (FEMA). Besides proving our system provides a certain level of protection, this accreditation also allows for lower cost flood insurance for District landowners and allows for more development.
The Drainage Districts work with many other agencies locally. We work with the Cities of Portland, Gresham, Troutdale, and Fairview, the Port of Portland, and community agencies and groups like the Columbia Slough Watershed Council, the Columbia Corridor Association, and neighborhood associations. By collaborating and working with a variety of partners, we are able to provide flood protection to our area while also fostering natural restoration and recreation development in the Drainage Districts.