Skip to main content

Multnomah County Drainage District



  • Existence: 1917 - 2019


The Multnomah County Drainage District (MCDD) helps protect lives and property from flooding by operating and maintaining 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, 12 pump stations, and 45 miles of sloughs, streams, and culverts.

MCDD also serves three other districts along the south shore of the Columbia River: Peninsula Drainage District #1 (PEN1), Peninsula Drainage District #2 (PEN2), and the Sandy Drainage Improvement Company (SDIC). The four districts collectively extend from the edge of Smith and Bybee Lakes on the west, to the Sandy River on the east.

Before the Districts were formed, the area was part of the Columbia River floodplain. It contained a natural system of stream channels, lakes, and wetlands that flooded annually. Numerous lakes existed, including Fairview, Switzler, Mud, Force, Smith, Bybee, and Ramsey Lakes. In summer and fall, the rivers receded, drying out the floodplain.

For generations, Native Americans inhabited the Columbia River floodplain. The Chinook tribes used the area to hunt and fish, and traveled between the Willamette and Columbia Rivers via the more shallow waters of the floodplain. Their principal food sources were salmon, sturgeon, and camas. Cedar longhouses were occupied seasonally.

All four Districts were formed in 1917. At that time the land was primarily agricultural and flooded throughout the year. Local interests built berms to help protect the land from flooding so they could farm year round and develop the land for industrial use. The 1936 Flood Control Act made the United States 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 Districts’ levee system.

Today, the 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 districts an assessment annually for our services, and cost share them for special projects.

for current info see