DEP memo re: USS Intrepid Pier 86 sewer rehabilitation

NYC 9/11 Public Portal Document

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REPORT FOR THE RECORD 331,000 Re: Intrepid Sea-Air-Space Museum, Pier 86 April 17, 1982 at 12th Avenue and 46th Street, Manhattan #82-075

In response to a request from John L. DiMartino, P.E., Assistant Commissioner, Director, Bureau of Sewers, an external and internal inspection was performed on the 6'-6"x8'-6" F.T.R.C. Double Barrel Overflow at the above referenced location. On March 15, 1982, a section of the overflow sewer had been exposed at the roof surface in preparation for the construction of the museum structure that will span the sewer. The external inspection of the exposed section of sewer revealed it to be in sound structural condition with no visible defects. An internal walk-through investigation of the double barrel sewer was made on March 29, 1982 during a period of non-peak flow and low tide. The following observations and defects were noted (refer to sketch). North Barrel 1. A one inch wide longitudnal crack extends approximately 5 feet in the common wall between barrels near the invert upstream of manhole A, 2. Approximately 5 feet downstream of manhole A, there exists a sealed (brick bulkhead) equalizer between barrels. 3. Approximately 5 feet downstream of manhole B, there exists an open equalizer faetxveen barrels. 4. Approximately 30 feet upstream of manhole C, a 4 foot square by one foot high mound of rock and debris was observed, 5. A one inch crack in manhole C extends from the side walls to the roof area. This structural crack shows definite signs of differential settlement. 6. Approximately 5 feet downstream of manhole C, there exists an open equalizer between barrels. 7. The section of sewer approximately 30 feet from manhole C to the outfall is in a deteriorating state with several large cracks evident in the common wall between barrels and side walls, South Barrel 1. This barrel has been bulkheaded in the vicinity of the tide gate chamber. 2. An accumulation of silt approximately one foot in depth extends from the bulkhead to manhole C. 3. The section of sewer approximately 30 feet from manhole C to the out-

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