The existing amil gates were constructed in the early 1970's as a flood control structure to operate in coordination with the dam system along Oyster Creek.  The amil gates are hydraulically activated during high water events to maintain a maximum flood elevation in Oyster Creek.  The amil gates are located at Char Lake near State Highway 6 (SH 6) and Brooks Street.

Over the past few years there have been concerns by the City and Gulf Coast Water Authority (GCWA) related to water leakage from the existing amil gates when the gates are in a normally-closed position.  The City and GCWA agreed to work on a resolution to this issue as part of a Settlement Agreement approved in 2012.  A Preliminary Engineering Report (PER) was completed which recommended options for replacement of the amil gates.  Various designs were considered in detail, but due to the complexity of the project related to existing soil conditions, groundwater, and maintaining current operations during construction, a revision to the design was required with revised cost. These were  updated in January 2017 and submitted to the City. In February 2017, City Council approved an amendment to the Brooks Lake Diversion Weir Agreement (Agreement) with Gulf Coast Water Authority (GCWA).  The Agreement stipulated that GCWA will pay 50% of the design and construction costs plus any interest on debt.  The City and GCWA will go through a "true-up" process to record final cost once the project construction is completed.  Once the construction contract is awarded, GCWA is to begin making their shared payments.  Once construction is completed, the City will own, operate and maintain the structure.

The design was completed in September 2017. The proposed design will have fixed weir walls and motor operated slide gates to allow the City to cross a wide range of expected flows.

The Engineering and Purchasing Departments worked to identify the procurement process that would provide the best value selection for choosing a contractor for the project.  It was determined that Competitive Sealed Proposal (CSP), under section 2269 of the Texas Government Code, would provide the best value selection process for this critical project.  In accordance with State code and City policy, the CSP process allows the City to select a contractor based on price and qualifications from weighted average selection criteria.  This method was selected due to the very specific approach of the construction for the temporary care of the water channel and temporary dam installation during construction that can have a great impact on upstream property owners if not properly cared for.  The evaluation was based on the following weighted criteria:

     -Price Proposal 55%  / Scope Management Plan 2.5% / Project Schedule 2.5%

     -Project Manager/ Personnel Qualifications 10% / Quality Assurance Plan 5%

     -Past Experience and References 20% / Safety and Environmental Records 5%

The Brooks Lake Diversion / Amil Gate Replacement Project advertised for CSP in October 2017 and six (6) proposals were received on November 2017.  A five (5) person team composed the evaluation committee with three (3) from the Engineering Department, one (1) from Public Works and one (1) from the design team.  The proposal price, technical information, interviews, and references were all considered in making the final recommendation. The following is the final ranking of the proposals:

The recommended contractor, NBG Constructor, Inc. was contacted and after negotiations has agreed to contract with the City for this project in the proposed amount of $3,759,018.  This project will be funded from CIP SW1401. The current available budget  for this capital project is $3,209,678. To complete the construction of this project, a budget amendment of $770,000 is requested. The available budget plus additional funding will cover construction costs ($3,759,018), construction administrative services ($62,435), material testing ($30,200), a temporary construction easement for ($50,000), and a 2% contingency ($78,025). As previously mentioned, 50% of the project cost will be paid by GCWA. Per discussions with GCWA, they have verbally agreed to move forward with the project and verbally agreed that shared cost reimbursement payments will reflect the most current estimated costs and the final costs after construction will go through a "trued up" process per the stipulations of the Agreement.

The scope of work for this project will include the construction of a temporary bypass channel to the north of the existing amil gates. The bypass channel will allow the existing gates to be taken out of service during the construction of the project. A new structure will be constructed in front of the existing amil gates, including a cast-in-place concrete weir structure foundation, walls, access bridge, access platforms, new downward opening gates, electrical components and miscellaneous items.  Assuming a Notice to Proceed in March 2018, the project is expected to be completed in March 2019 with a duration of 330 calendar days to substantial completion.

Staff recommends that the City Council authorize the execution of the construction contract with NBG Constructors Inc. for the amount of $3,759,018 and a budget amendment of $770,000 from the Surface Water Fund Balance for the Brooks Lake Diversion/Amil Gate Replacement Project CIP SW1401.