Online now at Mike Kirby’s blog:
…The three engineers that examined the dam for GZA in 2007 found a dam that had its problems, but a dam that was in no immediate danger of collapse. “Seepage was not observed near the toe or downstream of the dam and embankments.” The bulk of the leakage was in the top three courses of granite blocks in the spillway, and could be fixed by siphoning the water level and grouting these blocks. Both total rehabilitation to meet state standards, and modification of the dam by lowering the spillway level were possible. There was only $100,000 difference between the costs of demolition and those of lowering the spillway to elevation 446 so that it would not have so much pressure behind the dam. This would top the spillway with a cement cap beam, and secure it with anchors. The core wall of the dam is granite, anchored into bedrock. The “dam’s abutments consist of bedrock outcrops.” The buttressing effect of the curved spillway, anchored in bedrock, gives the dam strength that was not reflected in the so-called “gravity tests” given it by GZA…
The Upper Roberts Meadow Dam is no danger to anyone. It will undoubtedly be overtopped in strong storms, but the evidence is that it has been overtopped a number of times without any damage. There were two major problems with the State’s classification of the dam as dangerous. It was made without knowing how much water was in the reservoir. Even if the dam did break, it didn’t have that much water behind it…
The State also ignored the storage capacity of the diversion channel and the flood plain below the dam…
Our brainy nineteenth century engineers put their dam where even a catastrophic failure of the dam would do nothing more than flood three roads for a couple hours. Reservoir Road, Kennedy Road and Chesterfield Road. Not the heaviest trafficked roads in town. No matter how big the storm, a dam break would increase the water level no more than 1.25 inches at the Middle Dam. No domino effect…
You don’t get this federal money unless you can prove collateral damage to life and property. And MEMA and FEMA don’t like rehab projects or funding maintenance projects. They tell that up front to applicants. No to the “3Rs”, repair, reconstruct, and rehabilitation. They like problems fixed for keeps. So you make fraudulent statements and hope that no one notices…
See also:
Website: Save the Chesterfield Road Dam
Video: Board of Public Works Votes to Remove Upper Roberts Meadow Reservoir Dam (10/28/10)
Video and Slides: City Council Public Forum on the Upper Roberts Meadow Dam Resolution (10/27/10)
An Open Letter from The Friends of the Upper Roberts Meadow Reservoir and Dam (9/30/10)
The City’s decision to remove the Upper Roberts Dam appears to be based on a long-term cost comparison of alternatives to repair and remove the dam. GZA estimates the long-term cost of the two alternatives to be $1,893,412 for Full Rehabilitation and $1,200,000 for Removal. If the dam were reclassified to a lower hazard potential, however, the scope of repair work would be drastically reduced. Using costs from GZA’s itemized estimates, the long-term cost to rehabilitate the dam to the requirements for a lower hazard classification are estimated to be $566,453; less than a third of the cost of Full Rehabilitation and less than half the cost of Removal. Further, the risk of construction cost overruns are likely to be much less for the lower hazard rehabilitation alternative. This is significant because the City would be responsible for any cost overruns. [See PDF with detailed cost comparison]
Video: Dee Boyle-Clapp Rebuts Arguments for Removing the Chesterfield Road Dam (9/16/10)