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Trail Alternative #3 Sheetpile (City side) was considered; it would have been constructed on the city of San Leandro sedimentation pond (south) side of the levee (Figure 7). Under this alternative, sheetpile would be driven approximately 24 feet (7.3 meters) deep into the slope of the levee adjacent to the sedimentation pond. Three feet (0.9 meter) oflightweight fill would be placed on top of the slope to create room for the maintenance roads. Unlike the Preferred Alternative, the maintenance road would be only 10 feet (3.1 meters) wide, and the trail would also be 10 feet (3.1 meters) wide with one-foot (0.3-meter) shoulders. The narrower road and trail are caused by the steeper 3:1 levee slope on the sedimentation pond side alternative as opposedto the 3.6:1 slope on the Port side of the levee. The road and trail would be separated by a fence and a removable or fold- down railing would be installed on the sheetpile wall to prevent accidental falls into the sediment pond. Alternative #3 Sheetpile was withdrawn because: 1) the road and trail would be narrow; 2) the maintenance road would have an offset where the trail meets the road; and 3) because the three-foot vertical sheetpile wall would hinder maintenance work and reduce the capacity of the sediment pond. Trail Alternative #4 Levee Fill Was also considered, and involved placement of fill on the Port of Oakland side of the levee slope, anchored not by sheetpiles but by a 2: 1 slope down to the existing toe of the levee (Figure 8). This alternative would accommodate a 12-foot (3.7-meter) wide trail with a two-foot (0.6-meter) shoulder and a separate maintenance road. However, this alternative was withdrawn because adding the fill on top of the soft Bay mud ofthe levee could cause failure ofthe new trail as well as the existing levee; and construction would require intrusion into the adjacent wetlands. The last alternative, Trail #5 Alternative Alignment, considered a trail alignment around the east end of the Oyster Bay Slough that would connect with the existing trail on the Port of Oakland property without using a bridge over the slough. The trail would be aligned around the existing gun club, and through the City's wastewater treatment plant facility. No other alternate inland routes for the trail would be possible. Trail #5 Alternative Alignment was considered and was rejected because of . safety concerns related to the gun range and wastewater treatment plant. Construction Schedule, Equipment, Staging Area, and Employees It is estimated that construction of the bridge and trail segment. could be accomplished in approximately 120 days (16 weeks or four months). Key activities would include pile driving of the CISS piles for the bridge (which would take six weeks); construction of the bridge (four weeks); and construction of the steel soldier pile wall for the trail (12 weeks) (Chen, 2005). The heavy equipment that would be required includes two cranes and two generators used during the entire construction period; one pile driver, used for approximately eight weeks; and a drill machine, paving machine, and two rollers used for a shorter period of time. In addition, a total of approximately 60 concrete trucks would be needed for concrete placement at the two bridge abutments, for pier caps, and to pour the concrete deck and drilled holes. Another 200 trucks would be used for excavation and to deliver materials. An estimated 200 cubic yards of soil from excavation and drilling operations would be generated and would be trucked and disposed of off-site (Chen, 2005). Y 4204IS.00693.doc - 4/5/07 -6-