Inter-Departmental Correspondence

Department of Public Works



November 2, 2009


November 10, 2009







Honorable Board of Supervisors


James C. Porter, Director of Public Works


MidCoast Drainage Improvement Project - Cedar Street from George Street to Montara Creek in the Montara Area (Project No. M0209, F-149 [21])



Adopt a resolution increasing the Public Works Director’s authority to execute change orders (contract amendments) to the contract with Half Moon Bay Grading & Paving, Inc., to increase the “Not to Exceed” amount of $261,580 by an additional $65,000, to a new “Not to Exceed” amount of $326,580, in order to allow for payment of unanticipated project costs related to the MidCoast Drainage Improvement Project on Cedar Street from George Street to Montara Creek.



On March 17, 2009, your Board adopted Resolution No. 069989, which adopted plans and specifications, including conformance with prevailing wage rates scale requirements, and called for sealed proposals for the MidCoast Drainage Improvement Project on Cedar Street from George Street to Montara Creek (Project).


On May 5, 2009, your Board adopted Resolution No. 070100, which awarded and authorized execution of a construction contract for the Project with Half Moon Bay Grading & Paving, Inc. with a not-to-exceed amount of $261,580, which included a contract in the amount of $227,459.85, and the Director of Public Works’ authority to execute change orders (contract amendments) in an amount not to exceed $34,120.15.



Unexpected conditions have led to a determination that the original “not to exceed” amount is insufficient to complete this project. The factors which contribute to the increased costs include:



The Project specifications anticipated the use of existing native soil as trench backfill material, however after construction commenced it was determined that the native soil was unsuitable for this purpose. Public Works (Department) and Half Moon Bay Grading & Paving, Inc. have agreed to use the most cost-effective, yet suitable, imported material at an additional cost to the Project.



The Project specifications include a bid item for exposing and working around existing utility lines where they cross the proposed storm drain pipe. However, several additional utilities were encountered that require special care to avoid damage. Exposing existing utilities and working around them during construction and placement of a large diameter pipe is slow, labor intensive, and costly.



There are unanticipated contract costs resulting in work to relocate two sanitary sewer laterals. The laterals were initially believed not to pose a conflict with the proposed storm drain pipe based on the information provided to the Department from the sewer district. However, actual field conditions warranted the relocation work.



Additional work is required at the storm drain outfall area as a result of the recent heavy rains and to provide additional erosion protection to the creek banks.


This Department recommends that your Board consider these unanticipated costs and approve the recommended contract increase amount. Construction issues or conflicts often arise during construction of underground facilities, however, the issues that arose during this project have caused the Department to reevaluate the amount and degree of exploration and testing that must be accomplished during the design phase of future projects to minimize these unanticipated conflicts and costs.


Approval of this action contributes to the Shared Vision 2025 outcome of a Healthy Community by alleviating localized flooding which will benefit the public that use the roads and the adjacent property owners.


A resolution has been approved as to form by County Counsel.



The recommended increase of $65,000 in the not-to-exceed amount of the contract to allow for payment to the Contractor for the above-described expenditures is proposed to be financed with Mitigation Fees. Mitigation Fees were established by Ordinance No. 3277 and can be used within the area they are collected for road or drainage improvements. Upon completion of construction work, the Mid-Coast Urban Mitigation Fee Fund balance will be $94,704.99.


There is no impact to the General Fund.