ADDRESSING DEFICIENCIES IN THE VENTURA RIVER LEVEE SYSTEM

摘要

Originally constructed in 1949 by the U.S. Army Corps of Engineers, the Ventura River 1Levee System (VR-1) in Ventura County, California was an approximately 2.65-milelonglevee system placed along the bank of the Ventura River. The levee slope wasprotected with loose riprap revetment from the Pacific Ocean to river mile 0.92 then withgrouted riprap revetment to the upstream limit.In an August 31, 2007 letter to the Ventura County Watershed District (District), FEMAidentified potential levees or levee-like situations in Ventura County which FEMA hadreason to believe might provide base-level flood protection to the areas landward of suchlevees. FEMA’s letter provided the District with the opportunity to seek ProvisionallyAccredited Levee (PAL) designation status for some or all of those levees. After a periodof negotiation with FEMA, the list was refined to nine (9) levees, including VR-1 levee,which the District would consider for potential certification pursuant to 44 CFR 65.10.Tetra Tech, on November 25th 2008, was contracted by The District, to perform theanalysis for the PAL certification in order to meet the November 30, 2009 deadline datefor the submission of levee documentation packages to FEMA. In an evaluation reportdated February 20, 2011, Tetra Tech determined that the VR-1 levee could not becertified without rehabilitation of the system. With the PAL timeline expired, FEMA is inthe process of revising their mapping to reflect de-accreditation of this levee.The District is pursuing options with the U.S. Army Corps of Engineers to fully assessthe conditions (existing and future) and rehabilitate the levee. A Feasibility Study or aDesign Deficiency Study is being considered as likely routes to accomplish this work.