Levees: Delta-Wide Analysis
The California Department of Water Resources is supporting electromagnetic anomaly surveys of levees in the Sacramento-San Joaquin Delta. This effort is largely funded through FEMA’s Hazard Mitigation Grant Program, as well as monies from participating Reclamation Districts. Electromagnetic data, sensitive to subsurface features, were acquired to locate areas of structural weakness leading to a focused repair and mitigation strategy of levee reaches at risk of failure. Argus Technologies (a Tremaine Company) has surveyed 25 Delta levees to date. Thousands of anomalies have been located and classified according to pre-set criteria that evolve as the results of excavations are obtained. As the volume of data increases, an opportunity emerges to broaden the scale of analysis, from a localized or island level focus to a Delta-wide perspective. Are levee anomalies and failures randomly distributed or are there patterns that could lead to prediction models? Records and data relating to the development of natural and anthropomorphic levees, historic aerial photography, current remote sensing (lidar, hyperspectral), underlying geology, hydrodynamics, natural history, documented levee failures, as well as current and historic threats to levee integrity are used in conjunction with the anomalies in a comprehensive analysis.