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2016 STREET AND UTILITY IMPROVEMENT PROJECT FEASIBILITY REPORT CITY OF ST. ANTHONY VILLAGE WSB PROJECT NO. 2170-13 PAGE 5 3. EXISTING CONDITIONS 3.1 Sanitary Sewer The sanitary sewer system consists of 8-inch-diameter vitrified clay pipe (VCP) and 12- inch-diameter VCP which was installed in the early 1960’s. The joint sealing material in use at that time was typically an oakum and bituminous material. An internal inspection of the sanitary sewer within the project area was performed with a specially designed television camera. The structural condition of the 8-inch sanitary sewer pipe within the City of St. Anthony Village was determined to vary between fair and poor, with numerous offset joints, cracked segments, dips with solids deposition, and some root intrusion and mineral deposits at joints. The existing 12-inch sanitary sewer within the City of Columbia Heights was not inspected for this feasibility; however, the condition of the existing pipe is reported to be in good condition by Columbia Heights staff as the pipe has recently been rehabilitated using cured-in-place pipe technology. The segments of sanitary sewer televised with this project can be found on Figure 7 in Appendix A. 3.2 Water Main The existing water distribution mains within the project area were also installed in the early 1960s and consist of 8-inch cast iron pipe (CIP) within the City of St. Anthony Village and 6-inch CIP within the City of Columbia Heights. This system has had numerous breaks over the past few years and breaks will become more likely as the pipes are approaching 50 years of service. In addition, the cast iron pipes of this age commonly show corrosion and are prone to leaking. 3.3 Storm Sewer The existing trunk storm sewer system in the project area consists of a 36-inch reinforced concrete pipe (RCP) that runs along the west side of Stinson Boulevard NE with catch basins installed at the low points of the road. This storm sewer collects water from Stinson Boulevard NE and conveys stormwater to the west along 40th Avenue NE and eventually north outfalling into Silver Lake. There is also a small storm sewer system consisting of 12-inch RCP to 27-inch RCP located between 39th Avenue NE and 40th Avenue NE. This storm system conveys water into the 36-inch trunk line. 3.4 Streets Stinson Boulevard NE is currently a 42-foot-wide concrete street with integrant curb and gutter. Soil borings reveal that the underlying soils in the project area consist of silty sand fill, clayey sand fill, and lean clay with sand fill. A copy of the geotechnical soil boring logs prepared for the project by American Engineering Testing, Inc. in July 2015 may be found in Appendix C and the soil boring locations can be found in Figures 6 in Appendix A. 49