 As with channelization, levees are only found in the lower San Juan watershed. San Juan Creek is bounded with levees from upstream of Interstate 5 to very near its mouth at Doheny Beach, while Trabuco Creek has levees from upstream of Del Obispo Street (a continuation of the Ortega Highway) downstream to its mouth at San Juan Creek. Oso Creek has some raised banks, but it is not certain if those are levees. Smaller tributaries, such as El Horno Creek and Bell Canyon, do not have levees. Although the San Juan and Trabuco Creek levees are said to have a "fairly high level of protection currently", failure scenarios of levees in the San Juan watershed have been extensively studied, and they have been determined to possibly fail for a variety of reasons, some of which have already been demonstrated in the floods of 1996 and 2005. In response to the danger of another flood, work has begun on a new west-bank levee replacement that will finish in 2013.
