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support. The improvements for the 7 ' <br /> pp Ward Sewer are estimated to be $1,640,500. No <br /> change to the annual O&M cost is expected. <br /> 1.4 Union Street Sewer <br /> 1.4.1 Summary <br /> The existing brick pipes of the Union Street Sewer have aunite- a liner over the brick <br /> 9 tYP <br /> host pipe. The liner is failing and bricks are exposed for much of the length, with the pipe <br /> dimensions ranging from a 36-inch x 24-inch egg-shaped to 544nch round pipe. Active <br /> infiltration and defective connections are also present. The service area is mostly mature <br /> residential, commercial, and light industrial. Of the 4,050 feet of sewer north of Decatur <br /> Street, all but 310 feet lie beneath parking lots, alleys, streets, and buildings. These <br /> sewers also average about 14 feet in depth. <br /> 1.4.2 Conclusions <br /> The Union Street Sewer is literally 100 years old. The liner loss exposes the brick host <br /> pipe to further mortar loss and brick displacement. A failure of this sewer could impact <br /> downtown businesses and commercial areas, historic districts, and residential areas. <br /> Recreational areas near the Sangamon River could also be affected depending on the <br /> failure location. Extensive property damage is also possible, as with all of these critical <br /> sewers. The capacity of the sewer is expected to be sufficient for the foreseeable future. <br /> 1.4.3 Recommendations <br /> Seal the brick substrate, eliminate active infiltration, structural and operational defects, <br /> and service tap defects in the existing pipes using trenchless rehabilitation techniques. <br /> Where it is cost-effective, traditional excavated repair or replacement should be <br /> considered. Manholes should be treated with a spray-applied coating to stop infiltration <br /> and, if applicable, provide structural support. The estimated project costs for the Union <br /> Street Sewer rehabilitation are $3,158,765. No change to the annual O&M cost is <br /> expected. <br /> Page 4 of 119 BGM 11-050 <br /> Critical Sewers Rehabilitation City Project 2011-03 <br /> Facilities Plan Amendment <br />