Dams, levees, and basins are used to collect, store, direct, and convey surface water in a controlled manner and/or protect life and property during flooding events. The failure of a dam or levee can pose one of the most significant hazards to life safety, protection of property, and/or natural resources. According to the American Society of Civil Engineers (ASCE), since 1998, the number of unsafe dams has risen by 33% to more than 3,500, and the number of dams identified as unsafe is increasing at a faster rate than those being repaired. According to the Association of State Dam Safety Officials (ASDSO), over a third of our nations dams are already 50 years old and another 10 percent will reach the half-century mark in the next 10 years.
Historic events such as the Johnstown, Pennsylvania flood of 1889 and the 1928 St. Francis Dam failure in California; recent failures of levees in California and New Orleans; recent dam failures in Missouri, Washington, Michigan and Hawaii; and the recent failure of an ash basin in Pennsylvania and mine tailings in Mississippi and Florida underscore the hazards posed by dam and levee failures. According to ASDSO, dam and levee failures alone have caused at least 4,800 deaths since the late 19th century.
Exponent employs a diverse, multi-disciplinary team of geotechnical engineers, engineering geologists, geologic engineers, civil engineers, surface hydrologists, structural engineers, mechanical engineers, corrosion engineers, and materials engineers that provide for a complete and thorough evaluation of feasibility, design, construction, performance, and rehabilitation studies or root cause failure analysis of dams, basins or levees. Our staff have experience performing scientific and engineering analyses on a wide variety of topics, including the following:
- Site characterization through field and laboratory studies, geologic mapping, and fault studies
- Embankment design, construction, and performance
- Performance of mine and ash tailings
- Embankment monitoring (slope inclinometers, settlement surveys, piezometers, tiltmeters, remote sensing, etc.)
- Determination of root cause(s) of failure mechanisms
- Slope instability and base sliding stability
- Overtopping
- Soil piping
- Material degradation
- Operation issues
- Structural component failure
- Foundation weakening
- Earthquake loading
- Hydraulic analysis including
- Watershed delineation
- Storage capacity
- Outflow design capacity
- Seismic safety and stability
- Seepage flow analysis, both steady-state and transient
- Filter criteria
- Characterization of minerals and concrete using scanning electron microscopy (SEM)