To safeguard downstream residents, work now is under way in California to seismically upgrade the San Pablo Dam. The $54-million project involves removing an existing buttress, strengthening the downstream foundation using cement deep-soil mixing and constructing a new 85-ft-high by 950-ft-long buttress. The San Pablo Dam, located near El Sobrante, is an 89-year-old, 38,600 acre-ft drinking-water impoundment. It is managed by the East Bay Municipal Utility District (EBMUD), which serves 1.3 million people in parts of Alameda and Contra Costa counties. Photo: EBMUD Trestles carry flumes (above) for building the original dam, while soil-mixing augers now work to strengthen the
Thirty-two years after the last polychlorinated biphenyls (PCBs) were discharged into the Hudson River from manufacturing complexes, General Electric Co. began dredging on May 15 to remove 400,000 tons of contaminated sediment along a six-mile stretch near Fort Edward, N.Y. Additional dredging is planned downriver along a 34-mile section to Troy for a 2015 completion. + Image Source: General Electric Co. Drainage gallery will collect seeping PCBs for treatment and disposal. Related Links: Perdido Shatters Deepsea Records Fairfield, Conn.-based GE has not released costs, but the U.S. Environmental Protection Agency estimates total cleanup at about $750 million. Additionally, New York
A recent study by the Federal Transit Administration concludes that the nation’s largest transit agencies need at least $50 billion to bring their assets into a state of good repair and another $6 billion would be needed annually for normal maintenance. The Rail Modernization Study, completed in April at the request of Sen. Richard Durbin (D-Ill.) and 11 other senators, examined capital needs of the seven biggest U.S. rail transit agencies. It looked at older systems in New York, Boston, Chicago and Philadelphia, as well as newer systems in San Francisco, New Jersey and Washington, D.C. Combined, the agencies serve