Frequently Asked Questions
What is a levee?
A levee is an extended earthen berm or embankment intended to limit or divert the flow of water. The majority of the levees are made of sand which allows a small amount of water to seep through to reduce the water pressure on the levee (see “How Levees Work” graphic for a levee visual).
Where are the levees?
There are 27 miles of levee along the Columbia Slough and the lower Columbia River, from Smith and Bybee Lakes to the West and the Sandy River to the East.
What do the levees do?
The levees are designed to reduce the risk of flooding for an approximately 24,000-acre area that was once natural floodplain. Without the levees, much of this area would be seasonally flooded. The levees, along with a supporting system of ditches, culverts, and pump stations, collect or divert storm water and river water to keep the floodplain dry year round. This area now provides a diverse range of economic, residential, recreational, and ecological assets.
Why are the levees important?
The integrity and effectiveness of the levee systems are critically important to the future of the Portland Metropolitan Area. Important community resources behind the levees include
- Portland International and Troutdale airports, and the U.S. Air National Guard Base
- Metro Expo Center
- Transportation lines including I-5, I-205, I-84 and the MAX Yellow and Red lines pass through the districts.
- Residential and Commercial property: Approximately $16 billion in annual economic activity
- The Columbia South Shore Well Field which is the second largest source of drinking water in the State of Oregon
- Approximately 18% of the region’s buildable industrial land inventory and over $16 billion in annual economic activity
- Parks, recreation, and natural areas, including Blue Lake Park, Gleason Boat Ramp, Heron Lakes Golf, Portland International Raceway, Delta Park, the 40-Mile Loop trail and many others
- Local farms and agricultural areas
- Well-maintained levees also help property owners obtain low-cost flood insurance and to develop their properties.
Who is responsible for taking care of the levees?
Historically, the four Drainage districts have been responsible for maintaining the levee system which protected the land in the districts. The four Drainage Districts (the Districts) are:
- Peninsula Drainage District #1 (PEN 1)
- Peninsula Drainage District #2 (PEN 2)
- Multnomah County Drainage District #1 (MCDD)
- Sandy Drainage Improvement Company (SDIC)
The Districts maintain the system by repairing erosion, managing vegetation on the levees, testing and repairing pump stations, and ensuring that water can travel freely through the ditches and sloughs.
Levee Ready Columbia recognizes that, as the levee system becomes more important to the region, partners from around the region should participate in the certification and accreditation of the levee system.
Responsibility for Flood Preparation
What is the history of the levee system?
Local landowners began draining the land for agriculture in 1917. Over time, the drainage districts entered into partnerships with the US Army Corps of Engineers (the Corps) to build a more robust system of levees.
During the Vanport Flood in the spring of 1948, the Columbia River crested at 36.1 feet (NAVD 88 Datum) due to a heavy snow year and warm spring rain. On May 31, 1948, a major breach occurred on the western side of PEN 1, leading to several smaller breaches and the inundation of PEN 1, PEN 2, and MCDD. The flood destroyed the city of Vanport was destroyed and 15 people died.
The levee system was repaired after the Vanport flood by the Corps and private partners. Since then, the levee system has performed well and prevented flooding of the districts during many high water events, most significantly those 1956 (32.9 feet), 1964 (33.0 feet), and 1996 (32.5 feet).
What is Levee Ready Columbia?
Levee Ready Columbia is a Partnership of over 30 organizations including local, state, and federal government, and business, environmental, and community-based organizations who are committed to a common approach to flood plain management.
Levee Ready Columbia will assess the levee system to determine the current condition and identify whether investments, both structural and non-structural, need to be made to meet federal standards and provide the community with a reduced flooding risk. Levee Ready Columbia is ensuring that the levee system maintains standing in federal programs (FEMA, the Corps) to ensure the community receives the benefits of those programs (see below).
Levee Ready Columbia is working with the community to ensure that the levee system continues to reduce the risk of flooding of the assets behind the levees. This effort is a partnership of nearly 30 public agencies and community organizations. Each participant retains its own legal authorities and responsibilities while committing to contribute/complete specific actions beneficial to the completion of the overall project.
Why is Levee Ready Columbia happening now?
Levee Ready Columbia is preparing for the future. Five high water events have occurred in the last 120 years. We know there will be more high water events on the Columbia River. High water events are a regular occurrence on the Columbia River and proper precautions and preparations are necessary to avoid significant damage.
The levee system is in place because of thoughtful investments in the past. The area protected by the flood control system now plays a critical role in the region’s future, because important community, economic and environmental assets now rely on the flood control system. The system needs regular maintenance to continue to function well.
What happens if the levee system is not FEMA accredited?
If levees are not accredited, FEMA will treat properties in the area as if the levee system does not exist and much of the area will be remapped as a special flood hazard area. The cost of owning a home would increase as property owners would be required to purchase flood insurance through the National Flood Insurance Program (NFIP). Local regulations also restrict development in the special flood hazard area.
What happens if the system does not maintain standing in the RIP?
Failure to maintain the levee system to Corps standards puts the region at risk of losing federal assistance in maintaining the levee system during and after high water events. These may lead to higher costs for flood control in the future.
How much will it cost to assess the levees and make repairs or improvements? Who will pay?
The project partners are currently funding the engineering assessments on the levees but do not know the full cost of required fixes to ensure they meet federal standards at this time. The cost of maintaining the levees depends, in part, on the community’s desired level of protection. A higher level of protection (decreased risk of flood) usually means higher costs. Some benchmarks for the level of protection exist in the standards set by FEMA and the US Army Corps of Engineers. Maintaining the levees to these federal standards in the future will also have some costs which will be better understood after the current conditions of the levees are fully assessed.
The costs of building, maintaining, or repairing levees in other systems around the country vary widely. Unique river, weather, and soil conditions make it difficult to compare our system to those in other areas.
The Districts, Multnomah County, Metro, City of Portland, City of Gresham, City of Troutdale, City of Fairview, the Port of Portland and the state of Oregon have shared the costs of Levee Ready Columbia so far. Levee Ready Columbia budgeted approximately $3 million for investigation of the levees in PEN 1 and PEN 2. Approximately $4 million is budgeted for to the investigation of the levees in MCDD, SDIC, and SIDIC.7
What are the benefits of maintaining FEMA accreditation and good standing in the RIP?
When FEMA accredits the levee system and the system is in good standing with the Corps, the local community receives multiple benefits. First, the process of accreditation raises community awareness of flood risk. Second, the community is able to receive federal assistance during and after high water events. Third, the community is not required to pay for flood insurance through the National Flood Insurance Program (NFIP). Finally, FEMA treats the areas with accredited levees as having low flood risk; this ensures the continuation of existing economic development conditions in the districts.