Minutes 06-17-2014 - Laserfiche WebLink

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f. McGowan Sewer Interceptor Additional Rock Allowance and Approval of Budqet Amendment#9-E The Board considered approving Budget Amendment#9-E adding additional rock contingency to the McGowan Sewer Interceptor capital project budget and authorizing the Manager to sign. Chair Jacobs said this is on the regular agenda mainly as an informational item due to the costs. Kevin Lindley reviewed the following project overview as included in the abstract: This project has been underway since March 17, 2014. The overall project is approximately 85% complete and consists of 2,400 linear feet of 12" gravity sewer line and de-commissioning of the McGowan Creek Sewer Pump Station. The installation of this gravity sewer line will allow the County to take the 26 year-old McGowan Creek Pump Station off line, which reduced the annual maintenance costs for the system and avoids costly reconstruction of the aging pump station (see Attachment 1). The original estimated rock quantity for the 12" sewer line was 2,000 cubic yards. However, after constructing approximately 2,000 linear feet (83%) of this line, the Contractor has excavated 4,665 cubic yards of rock. Because of the large quantity of rocky material, the Contractor has been using a special back hoe designed to break up the blasted rock, which allowed it to be placed back in the trench. This avoids having to haul the rock out by the truckload for disposal and having to purchase and haul in select fill dirt to replace the rock that was removed. The County's engineering consultant, McGill Associates, is estimating that there could be an additional 1,209 cubic yards of rock left to be excavated to finish this project. If the consultant's estimate proves correct, the total rock excavated for this 12" sewer line would be 5,873 cubic yards. When compared to the original estimate of 2,000 cubic yards, the difference is 3,873 cubic yards. The rock excavation line item is paid at $120 per cubic yard of rock excavated, so adding an additional rock excavation amount of 3,873 cubic yards will increase the construction costs by $464,760. This estimate is based the best available data and is conservatively estimated to be sufficient to cover all rock for the rest of this project. This project has a unit price contract so that a contractor is paid per unit, in this case cubic yards, as the rock is excavated. The contractor will only be paid for the amount of rock excavated, regardless of the amount available in the budget for that particular line item. The project is being funded by a State Revolving Fund (SRF) Loan. The current available loan amount is $774,904. The original construction contract was for $597,813, and the engineering design and construction oversight was $94,200, leaving $82,891 to cover ancillary costs and contingency. To date, there have been change order requests from the contractor and other ancillary costs against this contingency in the net amount of approximately $40,000, leaving approximately $42,891 to go towards the extra rock excavation cost. Additionally, $57,814 was appropriated to cover costs of the project which cannot be reimbursed through loan proceeds, such as the loan origination fee and easement costs. This amount will still be sufficient to cover the costs for which it was budgeted. Commissioner porosin asked how likely it is for staff to anticipate these kinds of obstacles. He asked if this is unavoidable in these kinds of projects, or if something should have been done.