R2011-57 AUTHORIZING AMENDMENT TO AGREEMENT WITH HANSON PROFESSIONAL SERVICES, INC.

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Public Works Memorandum NO. 2011-20 DATE: April 25, 2011 TO: Honorable Mayor McElroy and City Council Members FROM: Ryan P. McCrady, City Manager Richard G. Marley, P.E., Director of Public Works Keith D.Alexander, Director of Water Management SUBJECT: Fourth Amendment to Engineering Agreement with Hanson Professional Services for the Lake Decatur Dam Repairs Project, City Project 09-02 SUMMARY RECOMMENDATION: It is recommended that the City Council approve the attached resolution authorizing a fourth amendment to the Agreement with Hanson Professional Services, Inc., (Hanson), for construction engineering services to assist with the inspection of the ongoing repairs to the Lake Decatur Dam for a fee not to exceed $104,900. The amendment authorizes an increase in the total engineering services fee from$296,582 to $401,482. PRIOR COUNCIL ACTION: Appendix A provides a summary of the prior Council action. BACKGROUND: Summary of the Major Construction History of Lake Decatur Dam Appendix B provides a brief summary of improvements to the Lake Decatur Dam. Lake a e D ecatur Dam J Repairs—Project Status P The Lake Decatur Dam Repair project began in June, 2010. The project includes the following work: 1. Repairs to the upstream face of the dam. 2. Rehabilitation of the mechanical systems that raise and lower the sluice gates on the north side of the dam. 3. Replacing the seal systems for the bascule gates and sluice gates. 4. Removal of gate heaters along the bascule gates. 5. Installation of a concrete patch on the downstream spillway of the dam. 6. Replace all eight cylinders on the bascule gates of the dam. In August, 2010, the City Council authorized three major change orders that were necessary to repair deterioration and damage to the south bascule gate. A clear condition of the bascule gates can only be determined when bulkheads are in place and water is removed from the gate allowing for a complete inspection. Numerous unknowns exist until the gates are dewatered and the gate is fully exposed. The change orders and delays also expend a significant amount of construction engineering services. In addition, in late August it was determined that the new hydraulic cylinders Page I 1