Title
Resolution to Approve a Professional Services Agreement with NTH Consultants, Ltd. to Design the Access Bridge Replacement Project at the Wastewater Treatment Plant, RFP No. 21-17 ($290,172.00)
Memorandum
Your approval is requested for a Professional Services Agreement with NTH Consultants, Ltd. (NTH) in the amount of $290,172.00 for professional engineering services to design the Access Bridge Replacement Project at the City's Wastewater Treatment Plant (WWTP).
The City's WWTP is located in Ann Arbor Township and operates 24 hours per day, seven days per week. Access to the WWTP is provided by a roadway leading from Old Dixboro Road to the plant entrance that includes a bridge spanning the Huron River. The WWTP access bridge is 85 years old and the bi-annual bridge inspection performed in 2020 identified the bridge to be in fair condition and in need of replacement.
The current road and access bridge are located along a 650-foot by 75-foot easement east of Old Dixboro Road. A new bridge must be located on property south of the existing bridge and will require realignment of a portion of the access road. Property along the south side of the access road is privately owned and City staff has begun discussions with the property owner to obtain an easement needed for construction of the project. The final easement agreement will be based upon the design engineer's preliminary project study, approved preliminary plans, recommendations and property needs for the new access road and bridge.
There are several site conditions that add complexity to the design and construction of this project. An artesian aquifer is known to exist within the vicinity and management of this groundwater condition will be critical. Work will be required in wetland areas and structures may need to be placed in the Huron River to support the new bridge similar to the existing one. In addition, the existing bridge must remain in service while the new bridge is constructed as it provid...
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