Detection of damage to the boundary conditions of structures can be equally important as detection of structural damage. Civil structures sit on foundations which are, ideally, constant over time and are integral to collapse prevention. Any processes that compromise the foundations or the soil around them also constitutes damage to the structure. Bridge structures as well as embankments near roadways and viaducts can be particularly prone to this kind of attack when high-velocity water flows transport sediment away from the bridge foundation (scour). This process can be difficult to detect because 1) it happens out of sight, underwater; and 2) scour holes tend to grow and shrink at time progresses and materials are either carried away or deposited by the water. In this study, use of a buried-rod scour detection system based on magnetostrictive and magnetic flow sensor arrays is investigated. For buried-rod scour detection systems, an array of small, flexible, strain-sensitive rod sensors is distributed around the foundations which generate dynamic signals they are waterborne and static signals when buried. The pattern of static and dynamic signals reveals the depth of scour around the structure. Magnetostrictive sensors are appealing for this application due to their robustness. In this paper the effectiveness signal processing and scour detection algorithms are explored for water-coupled magnetostrictive whisker sensors of varying geometries to determine their sensitivity and the thresholds for false alarms and missed alert conditions at varying flow rates. Experimental laboratory data is utilized for this study.

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