ABSTRACT
Americans should find comfort in knowing that millions of their fellow citizens are working every day to ensure our security at every level—federal, state, county, municipal. Utilizing the protection-in-depth approach, which requires that adversaries defeat several protective barriers or security layers to accomplish their goal, water infrastructure can be made more secure. Protection in depth is a term commonly used by the military to describe security measures that reinforce one another and mask the defense mechanisms from view of intruders, thus allowing the defender time to respond to intrusion or attack. In water infrastructure security, protection in depth is used to describe a layered security approach. A protection-in-depth strategy uses several forms of security techniques and devices against an intruder and does not rely on a single defensive mechanism to protect infrastructure. Because the primary threat to active security barriers is that vehicles will attempt to crash through them, their most important attributes are their size, strength, and crash resistance.
