The City contracted with Pacific Hydrotec Corporation for the construction of Magnolia Reservoir and Booster Pump Station Rehabilitation Project.  The reservoir repairs consist of crack, spall, and joint repair, construction of seismic curb, roof waterproofing, rust spot repair, and the addition of a fall protection system. Site Improvements include rerouting the existing sub-drain sump pump piping, replacement of the sump hatch and sump vault lid and hatch, repair of the overflow flap gate, construction of a new parking lot and ADA ramp, installation of bollards and a mow strip around the reservoir, and replacement of the meter vault and piping. The repair work for the pump station consists of replacement of the existing engine and booster pump, replacement of the existing exhaust system, replacement of the existing catalytic converter, replacement of two 10-inch butterfly valves, replacement of the 10-inch check valve, refurbishment of the existing flow control valve, and replacement of the roof and existing removable dormer.

During construction of the Magnolia Reservoir and Booster Pump Station Rehabilitation Project, additional unforeseen conditions were encountered.  It was discovered that the reservoir waterstop (the sealant system for the bottom of the floor joints) was not 100% intact when the reservoir was being drained for the project work. Water was seeping back into the reservoir through several spots of the floor joints.  This was not observed during the assessment of the reservoir in the design process. The project proceeded with the original floor joints sealants scope, with the understanding that the sealants would correct the waterstop problem. However, staff observed a leak in the reservoir following completion of the floor joint sealant replacement work. After thorough investigation and consulting with the sealant company, the contractor has recommended this issue be addressed by installing the Combiflex System, a secondary joint sealant system that consist of sealant strips that cover the top of the floor joints.  This secondary joint sealant system is not part of the original scope which would require a change order to the contract.

A second item requiring out-of-scope work involves the addition of noise reducing acoustic panels for the new radiator assembly. The replacement of the pump engine required a new cooling system which added the installation of a radiator fan outside of the pump station building.   However, noise generated from the radiator fan is higher than expected and causes nuisance to nearby residences.  A sound study was conducted which recommended the installation of acoustic panels to mitigate the unexpected issue. 

The additional fees for the secondary sealant system and acoustic panels are $119,495 and $96,339.46 respectively. The additional scopes will increase the contract price from $3,514,053.35 to $3,729,887.81, a $215,834.46 increase.  The fees for the two (2) additional scopes along with the previous change orders put the project cost over 10% of the original contract price.

There is no impact to the General Fund. This cost will be financed with Water Funds, in the amount of $215,834.46.

It is recommended that the City Council:

• Approve Change Order No. 3 to the existing contract with Pacific Hydrotec Corporation, increasing the existing Agreement amount from $3,514,053.35 to $3,729,887.81, a $215,834.46 increase;

• Approve 70 working days of time extension for the additional scopes; and

• Authorize the Public Works Director to execute Change Order No. 3 to the contract agreement on behalf of the City, and make minor modifications as appropriate thereto.

By: Rebecca Li, Sr. Civil Engineer