Corps completes Mill Creek levee system periodic inspection

Published Feb. 7, 2011

WALLA WALLA, Wash. –  The Mill Creek Flood Reduction Project systems P and Q, which is operated and maintained by the Mill Creek Flood Control District (Walla Walla County), received an overall system rating of “minimally acceptable” following their most recent U.S. Army Corps of Engineers periodic inspection reports finalized on Nov. 19 (system P) and  Dec. 10, 2010 (system Q). 

The levee system’s “minimally acceptable” rating means it remains eligible to apply for federal rehabilitation assistance if it is damaged in a flood or storm event. Corps of Engineers project ratings do not determine final eligibility under the National Flood Insurance Program, a FEMA-managed program. Certification documentation is the responsibility of the levee sponsor. For information concerning the National Flood Insurance Program contact in relation to this levee system, contact the levee sponsor or the Federal Emergency Management Agency (FEMA).

The upstream end of both systems is located adjacent to the east edge of the City limits of Walla Walla near the Mill Creek Gauging Station and continues through the city. The downstream end of the system is located about one-half mile west of the city limits at Gose Street. The project was originally constructed during the 1930-40s, completed in 1942. The concrete paving of the Mill Creek Channel, through the City of Walla Walla, was completed in 1948. Many improvements and repairs have been made to the system over the years. Significant channel rehabilitation improvements were constructed during the 1980s. Numerous homes, businesses, schools, industrial buildings and farms are protected by the levee systems.

“Public safety is the number one goal of the National Levee Safety Program,” said Herb Bessey, Walla Walla District’s Levee Safety Program manager.  “We want to make sure levee systems are reliable and do not present unacceptable risks to the public, economy or environment.”

Inspections and assessments provide continuous feedback about levee systems and their reliability and are a critical part of the Corps’ Levee Safety Program. Routine inspections, conducted annually, focus on the operation and maintenance of the project. These annual inspections verify the project sponsor operates and maintains the levee to achieve the maximum benefits the levee was designed to provide.  Routine inspection items include vegetation, encroachments, drainage structures, erosion, animal burrows and culverts.  Routine inspections result in an acceptable, minimally acceptable or unacceptable rating and affect the project’s eligibility for federal rehabilitation assistance under Public Law 84-99 if damaged in a flood or storm event. 

The periodic inspection is the next level in the levee safety program and is conducted by a multidisciplinary team, led by a professional engineer.  It includes a more detailed, comprehensive and consistent evaluation of the condition of the levee system and will be conducted every five years. Activities under the periodic inspection program include routine inspection items; verifies proper operation and maintenance; evaluates operational adequacy, structural stability and, safety of the system; and compares current design and construction criteria with those in place when the levee was built. 

The final periodic inspection rating is based upon the routine inspection items, and includes an acceptable, minimally acceptable or unacceptable rating. Additional periodic inspection information that will be shared with the project sponsor includes identification of components and features that require monitoring over time.

The executive summary of the levee’s most recent periodic inspection reports can be obtained by contacting Herb Bessey at (509) 527-7144.

The National Levee Safety Program Act of 2007 directs the development of a national levee safety program, in addition to the inventory and inspection of levees nationwide. More information about the National Levee Safety Program is available on the Web at www.nfrmp.us/ncls/index.cfm

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Release no. 11-15