City Council awarded the FY20 Sanitary Sewer Manhole Rehabilitation project contract to SoCal Pacific Construction Corp., dba National Coating and Lining Co., on May 26, 2020.  The scope of the project (PWP# WA-2020-250) was to rehabilitate seventy sanitary sewer manholes that were exhibiting groundwater infiltration. Manhole degradation and structural defects can be a factor in the infiltration, but the primary cause in most cases is the high-groundwater table in Sparks, which results in constant hydrostatic force on manholes.  In some cases, the hydrostatic force leads to groundwater infiltration that unnecessarily reduces sewer collection system and Truckee Meadows Water Reclamation Facility (TMWRF) capacity and increases treatment costs. 

 

The proposed change order includes an additional thirty sanitary sewer manholes to be rehabilitated to mitigate groundwater infiltration and address structural degradation. The additional thirty manholes were identified using assessments performed by the City’s Public Works Division.

National Coating and Lining has performed well throughout the original contract.  Utilizing the existing contractor to perform the additional manhole rehabilitations provides efficiencies because the scope of work mirrors their existing contract and they have gained experience working on the City of Sparks sewer collection system.  

 

Attachment 02 – Sanitary Sewer Manhole Rehab – Flow Meter Exhibits demonstrates the success of the original contract manhole rehabilitations in reducing groundwater infiltration to the collection system and TMWRF.

 

The proposed change order with National Coating and Lining provides for the complete rehabilitation for an additional thirty sanitary sewer manholes, depicted in Attachment 01 – Manhole Rehab CO1 Vicinity Map.  The change order will be funded using the FY21 Manhole Rehabilitation program.  The change order proposed fee is $231,517.00, the original contract was $638,849.00, and the new total is $870,366.00.