U.S. Fish & Wildlife Service Low Hazard Dams - Association of State ...

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U.S. Fish & Wildlife Service Low Hazard Dams - Association of State ...

STANDING OPERATING PROCEDURESThe three types of failure previously described are often interrelated in a complexmanner. For example, uncontrolled seepage may weaken the soil and lead to astructural failure. A structural failure may shorten the seepage path and lead to apiping failure. Surface erosion may result in structural failure.Most embankment failures from piping occur along outlet conduits wherecompaction of the fill material is difficult.6.3 Resources and Procedures for Making Temporary EmergencyMeasures6.3.1 Responding to an Emergency SituationAfter making appropriate notifications to the RDSO of the changing dam conditions, theRefuge Manager should initiate efforts to prevent or delay failure of the dam. Any repairwork to prevent the dam from failure should be undertaken only if working conditions aresafe. Because of the likely limitation on time, it is important to identify availableresources quickly. Any emergency repair will require equipment, materials, labor andexpertise. If feasible, materials such as clay fill, sand, gravel, stone, riprap, sandbags,cement, plastic sheeting, geotextile, etc. and equipment for handling these materialsshould be kept at the site. If this is not possible, then prior identification andarrangements of locally available off-site materials and equipment should be made alongwith a current list of local contractors and other sources of labor and equipment.When reporting a dam incident to the RDSO, remember that when locating problemareas, all directions, e.g., “left of,” or “right from,” are taken while facing downstream.Items that should be reported include:1. Name of the dam and its locations.2. Nature of the problem (e.g., excessive leakage, cracks, sand boils, slides, wet spots,etc.).3. Location of problem area in terms of embankment height, (e.g., about 1/3 up from thetoe) and location along the dam’s crest (e.g., 100 feet to the right of the outlet orabutment) and whether on the upstream slope, crest, or downstream slope.4. Extent of the problem area. This can be satisfactorily established by pacing.5. Estimated quantity of unusual flows as well as whether the water is clear, cloudy, ormuddy.6. Water level in the reservoir below the dam’s crest or below the spillway, or the staffgage reading.7. Is water level in reservoir rising or falling?8. Name and how to contact person making report.9. Did the situation appear to be worsening while being observed for this report?6-9Revision No. 0October 2008

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