R2019-89 Resolution Authorizing a Professional Services Agreement with Hanson Professional Services Inc. for Lake Decatur Dam Gates Evaluation

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-2- Hanson Professionai Services has provided Lake Decatur dam engineering and repair services to the City for the past 15 years. Since they are the firm that is most familiar with the dam, and located nearby in Springfield,they were contacted to provide the proposed bascule gates evaluation. Hanson has assembled a turnkey operation to perform the inspections. Their team � includes Christy Foltz, a respected local subcontractor who will provide the necessary equipment to access the gates and hydraulic cylinders. Underwater inspection of the front face of the bascule gates will be performed by Global Infrastructure who completed the last major rehab of the bascule gates and has provided underwater inspections of the upstream face of the dam in the � past. Hydraulic review and testing of the system will be conducted by John Henry Foster, a firm � that currently services the dam hydraulic systems. The evaluation is complex and encompassing in order to determine the problem and its likely ' cause. The scope of work is composed of four major tasks: 1. Hydraulic Cylinder Testing—All 8 hydraulic cylinders, encompassing both the north and south bascule gates will be tested to assure that there are no other lurking problems with � the large pistons. 2. Gate Inspection—Both bascule gates will be examined for possible damage. This will include the use of divers to inspect the upstream face of the gates. 3. Upstream Face of the Dam Inspection—With divers mobilized at the site,we will have them inspect the upstream (lake side) face of the entire dam. This portion of the dam has not had an underwater inspection in approximately 15 years. 4. Preparation of a Summary Report and Recommendations. This will include the likely cause of the December gate failure and specify the follow-up work necessary to design , the necessary repairs. Task details are on pages A-1 through A-3 of the agreement. BUDGET/TIME IMPLICATIONS: The services are not to exceed $153,900 and will be paid , from the Water Lake Capital Fund. These services need to be performed when the air temperature is well above freezing and water is not flowing over the dam, which is typically during the summer and fall months. � POTENTIAL OBJECTION: None foreseen. INPUT FROM OTHER SOURCES: ' The following City staff reviewed and approved the agreement in May: Gregg Zientara, Director of Financial Management Wendy Morthland, Corporation Counsel STAFF REFERENCE• Matt Newell, Public Works Director, Keith Alexander, Water Production Manager. Matt Newell will be in attendance at the City Council meeting to answer any questions of the Council on this item.