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the southbound work, it became apparent that there is insuff;cient width to maintain two lanes of traffic as planned. This required the contractor to add an additional phase of construction, during which the approach slab would be constructed in three sections (similar to the northbound lanes) instead of two sections as proposed in the plans for the southbound lanes. The additional phase required additional traffic control including K-rail rental, striping, forming, and rebar, and it also created some inefficiencies, adding several workdays to the project. City staff and the contractor negotiated the cost of having six construction phases instead of five and completed Change Order No. 1 in the lump sum amount of $54,435. As previously stated, there are five change orders to date; the other four are minor and, in aggregate, reduce the contract by $1,157, making the total of the five change orders to date $53,278. 2. Additional Epoxy Crack Injection at West Las Positas at G-3 Channel and Owens Bridge at Chabot Channel (PCO No. 6) The project plans identified a total of 853 linear feet of epoxy crack injection to repair cracks in the box culverts for these two bridges. The epoxy crack injection seals cracks and prevents corrosion of the reinforcing steel. During design, the number of cracks to seal were estimated based on the visual appearance of the cracks. During construction, the crack surfaces were cleaned and routered in preparation for the injection of epoxy. This process revealed that the cracks extended much further than anticipated by visual observation. In addition, the estimate did not account for the cracks on each face of the center wall, significantly under-estimating the number of cracks requiring repair. In total, 2,213 linear feet of cracking was prepped and repaired under the epoxy crack injection line item. This work is paid for at the linear- foot unit price cost as bid by the contractor. Estimated quantities used at bid time and actual quantities measured during construction are often slightly different. At the close of the project the normal process is to issue a balaiicing change order to adjust the contract total to reflect the actual quantities measured during construction. While this project's increase in measured quantity of crack repair is larger than is normal, staff determined it best to follow the normal process and authorized the work be completed. This decision was made because returning to complete the additional crack repair work would have significantly increased the cost due to the costs associated with permitting which require the work to be completed during the dry weather before October 15, diversion of the low flow in the channel during the summer to allow the work, and the pollution containment measures required to be in place during the work in case of unexpected weather. In short, it was best to accomplish the work as part of this project compared to performing it later as another project. The balancing change order will increase the epoxy crack injection contract line item by 1,360 linear feet at $50 per linear feet, cr a total of $68,000. 3. Additional Waterline Work at Santa Rita and Arroyo Mocho (PCO #9) The project plans and record drawings showed the potable water pipeline as a ductile iron pipe extending north of the bridge in a straight line. The water pipeline was "potholed" immediately adjacent to the bridge during the design. However, during construction, as the contractor worked to excavate the pipeline to install the isolation valve required to north of the bridge, the pipeline was not found in the expected location, straight north from the pothole location. The contractor dug several holes but was unsuccessful in locating the pipeline. Eventually, with the help Page 5 of 7