2011 Stormwater Annual Report - Boston Water and Sewer ...

to the NDBST and to Deer Island to be treated, while stormwater flows generated fromvery large storms are directed to the MBDC. Outfall 18L087 near Mother’s rest inDorchester was no longer needed so it has been eliminated.a. Storm Drain and Sewer Maintenance by BWSC StaffThe Commission’s Operations Division is responsible for smaller sewer and drain relatedrepair, maintenance and cleaning jobs, as well as some television inspections of sewersand drains. In 2011, the Commission jetted, vactored or rodded 422,852 linear feet ofpipe.In 2011, the Commission owned five (5) “vactor” high-pressure cleaning trucks to cleanaccumulated materials from sewers and drains, six (6) jet trucks, one (1) multi-roddertruck, and two (2) hydraulic bucket machines to clear blockages. To determine wherestructural deficiencies exist and where repairs are needed, the Commission crewsperformed television inspections of 25,687 linear feet of sewer and drain pipe in 2011.In conjunction with the storm drain and catch basin cleaning programs, the Commissionroutinely clears debris from twelve (12) brook inlets and outlets throughout the City.Since the primary purpose of this practice is to prevent upstream flooding, the cleaning istypically performed immediately prior to major storm events and usually they arechecked after storm events to determine if follow up cleaning is needed. The locationsand frequency of cleaning is provided in Table 3 – 1.b. Catch Basin MaintenanceThe Commission has approximately 31,752 catch basins in its sewer and drainagesystems. Other catch basins in the city are owned by other public agencies such as thestate Department of Conservation and Recreation, Mass Department of Transportation, orare located on private property.The Commission currently owns six (6) clamshell trucks. Commission forces have beenaugmented by contract forces and equipment since 2001. Contract forces currently cleanany catch basin containing twenty (20) inches or more of sediment. Contractors typicallycomplete two passes through the city each year cleaning basins as directed by theCommission.In 2011, Commission and contract forces performed 14,640 catch basin cleanings. Catchbasin cleanings are currently transported to the Material Handling Facility on AlfordStreet, where they are temporarily stored until transferred for proper off-sitedisposal/reuse at and approved facility. An estimated 4,680 tons of material taken fromsewers, drains and catch basins was transferred by the Commission’s contractor in 2011.It is not known how much of the material transported was just from the catch basins,although it is believed to be a majority of the amount.3 - 2