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See Council meeting Minutes and City Engineer Reports for related information. Use QuickLinks in the menu on the left side of this page to access those areas. Minutes of the February 18th Council meeting will be of particular interest to those seeking detailed information regarding activity related to Lake Berkeley dam. Also, the FAQ 'Dam, Spillway, Lake' may be of interest. That link is in the FAQ menu on the lower left side of this page.
Update March 9, 2010
Two FEMA representatives came this morning and examined the dam area with the Mayor, the City Administrator, Frank Lombardi, our city engineer, and the Piedmont Geotechnical engineer. All engineers present except FEMA believe the large new crack in the dam surface is additional evidence of major internal damage done in the September storm event. FEMA has completed what they call a “field estimate project worksheet” which they describe as still open to revision before we would need to begin the appeal process. They say they will reconsider their worksheet in light of this development but are making no commitments as yet.
The Mayor continues to work with our federal legislators whose support is much appreciated. She has completed an application for an earmark to the federal 2011 Water and Energy Bill which she submitted to Senator Isakson. We continue to hope that FEMA may become convinced by the available evidence to support the entire scope of the repair effort which they agree is necessary, but so far they have only increased their support level from 11% to @19% of the project. That is certainly progress for which we are grateful, but it’s a long way from what we believe is appropriate. The Mayor has today sent the following significant points for consideration to all our federal legislators:
Berkeley Lake Dam Repair
Significant Points for Consideration
The City and FEMA agree that:
1. The dam was constructed before there were standards.
2. Sometime later, the state created the Safe Dams Program (SDP).
3. Shortly thereafter, around 1978, the SDP inspected Lake Berkeley Dam and found many deficiencies.
4. In 1980, the City renovated the dam to correct the deficiencies. The plans for this renovation followed the Safe Dams Program standards in place at that time, and the project was permitted by SDP.
5. Visual inspections were made on an annual basis thereafter, and in 1996, they noted “wet spots” on the dam.
6. The “wet spots” were investigated by the City in 2008. Hand Auger borings were drilled to see if there was an elevated ground water surface in the dam. There was no indication that the groundwater level inside the dam was elevated.
7. The incident (September, 2009 storm event) occurred, and a slope failure occurred on the dam’s downstream face.
8. After the storm, hand auger borings were made. They indicate that the groundwater elevation inside the dam is elevated.
9. The elevated groundwater is causing the dam to be less stable than is called for by Safe Dams regulations.
10. The internal drain system installed in the 1980 renovation is not working to collect the ground water and pipe it away from the surface.
FEMA’s position is that the incident-related damage is limited to the expressed slope failure area (the part that one can see with the naked eye).
The City’s position is:
1. The elevated ground water surface is lowering the dam’s stability. The lowered stability is what caused the localized slope failure. This is due to the storm event overloading the internal drain system, because investigation into the wet spots in 2008 revealed no elevated ground water.
2. The increased ground water elevation is the problem that must be corrected, or new failures will occur. On March 8, 2010, the City’s engineers discovered a new failure area approximately 4 times the length and to the left (when looking downstream) of the original failure.
3. The reason for the new failure area is the same as the first – the internal drain system has not been functioning since the September disaster event to intercept the groundwater elevation in the dam. This is causing the dam to be less stable than it was designed to be.
4. Additional hand auger borings taken on March 8, 2010 continue to reveal elevated groundwater elevations, which were not present in hand auger borings before the September disaster event.
Click 'read more' to view a chronological list of updates regarding the irregularity at the Lake Berkeley dam.
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