The Sacramento / San Joaquin Delta is the hub of California's water distribution system, providing fresh water to over 20 million Californians and directly supporting our $50 billion/year agricultural industry. A network of over 1,100 miles of levees circumscribes Delta "islands" that lie as much as 10m below sea level. Unlike traditional flood control levees that are intermittently loaded during high water events, the Delta levees constantly impound water and have as little as a meter of freeboard at high tide. A breach along any segment of a levee system inundates the island, resulting in potentially hundreds of millions of dollars in loss. The Delta lies in a region of moderate seismicity at the eastern margin of the San Andreas fault system. Earthquakes pose a particularly onerous risk to Delta levees due to the potential for multiple simultaneous levee breaches. This presentation will discuss a multi-faceted research program that studied the response of levees to earthquakes, including a field modeling study, centrifuge modeling, laboratory testing, analysis of field case histories, development of a system risk assessment framework, and development of a nonlinear consolidation code that includes the effects of secondary compression.