Abstract:
Flooding has become a major concern especially in the coastal and/or low-lying communities in the face of sea level rise and climate change. Levees are the first line of defense against flood water while many of them are poorly maintained or simply obsolete in the light of the current design standards. Property owners behind deteriorated or obsolete levees may have to bear a high flood insurance premium due to the flood zone category given to the area where their properties are located. Upgrading those levees to the current standard and the required level of functionality is often conducted in order to have the FEMA’ s flood zone designation changed, so the property owners in the affected zone can enjoy a lower property insurance cost.
Southern California, particularly Orange County, has been upgrading existing levees along its drainage channels to achieve this exact goal. This paper will discuss the levee upgrade of the Huntington Beach Channel and Talbert Channel Repair Project where more than 16, 000 linear feet of steel sheet piles were installed. Sheet piles were selected for their design flexibility, structural integrity, ability to cutoff seepage water, and long service life. Most of the sheet piles were specified to be pressed-in due to the noise and vibration concerns around existing homes standing just behind the levees. The channel’ s waterway was too shallow for bringing in a barge and the land side right of way behind the pile line was wide enough for flatbed trucks to bring in sheet piles and for a crawler crane to unload and pitch them to the press-in piling machine; allowing all the work to be conducted on land. The overall sheet pile installation took 230 days to complete. This paper will look at the design and construction aspects of the levee upgrade project.