Agenda

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12.

Work Session and Regular Meeting

Meeting Date:	06/26/2018
Department:	Public Works
Pillars:	Excellence in Asset Management Optimize the Addison Brand

AGENDA CAPTION:

Consider Action to Approve a Resolution for a Professional Services Agreement with Nathan D. Maier Consulting Engineers, Inc., for the Design of the Vitruvian Park - Farmers Branch Creek Dredging Project and Authorize the City Manager to Execute the Agreement in an Amount not to Exceed $158,000.

BACKGROUND:

Farmers Branch Creek enters the Town of Addison approximately 40 feet east of Bella Bridge in the Vitruvian Park area. During the redevelopment of the Vitruvian area, the Town created an enhanced water feature which included a new impoundment of water. In urban environments such as this, "on-stream" waterways are susceptible to silt and sediment build up. Construction on the Vitruvian Park waterway was completed in 2011, and since that time a considerable amount of silt and sediment has built up in the creek. This sediment must now be removed to restore the storage capacity of the water body. This project will also improve the overall health and ecosystem of the pond, and enhance the aesthetics.

On-stream waterways are regulated by the US Army Corps of Engineers (USACE) and as such require special permitting by that agency prior to any de-silting activities. Typically, dredging projects can be handled by one of two permit types, Nationwide Permit or a Letter of Permission. The type of permit is largely dependent on the means and methods of dredging, which will be identified during the design.

Nathan D. Maier Consulting Engineers (NDM) was selected by Request for Qualifications (RFQ) in late 2017. They have a significant amount of experience with Farmers Branch Creek, having performed several flood related analysis and designs along it's limits. They also have good relationships with the Texas Commission of Environmental Quality and the US Army Corps of Engineers. The scope of the design will be broken down into several tasks:

Task 1 - Meetings and Coordination - NDM will provide full coordination throughout the project including coordination with the Town, Town's attorney's working on the Texas Commission on Environmental Quality (TECQ) permit amendment, potential contractors, and the City of Farmers Branch.
Task 2 - Field Reconnaissance, Data Review, and Survey - NDM will perform a full series of survey's to establish elevations and depths of the silt.
Task 3 - Geotechnical Services - NDM will perform silt/sediment analysis and testing to determine the the type of silt and the presence of any contaminated materials.
Task 4 - Removal Alternatives and Preliminary Plan Development - NDM will analyze the various types of dredging to identify the most effective approach for this project. NDM will also evaluate the need for make-up water during the construction activity to meet the Town's water rights permit requirements. NDM will also identify construction staging and access areas.
Task 5 - Regulatory Permitting and Submittals - NDM will prepare and submit permit applications to the USACE and TCEQ. NDM will coordinate all aspects of the permit process up to permit approval. NDM will also coordinate with Texas Parks and Wildlife, if necessary, related to the potential impacts of the sediment removal.
Task 6 - Sediment Removal Construction Plans - NDM will develop, biddable construction plans for the removal of the sediment. They will also develop an opinion of probable construction cost and technical specifications.
Task 7 - Bidding Assistance - NDM will assist the Town during the public bid phase of the project including: preparation of addenda, answering questions, attending the pre-bid conference, preparation of the bid tabulation, and contractor reference checks.
Task 8 - Recirculation Pump - The Town is currently experiencing maintenance issues with a recirculation pump located just upstream of weir 2. Because of this pumps' location relative to the weir, it has issues related to the accumulation of sediment which results in blockage of the pump intake. NDM will assist the Town with evaluating the problems with the pump in an attempt to provide and engineered solution. This task will be performed on an hourly, time and materials basis and only by prior authorization from the Town.

Funds for this project are budgeted for in the Stormwater Capital Projects Fund in the amount of $300,000. The total costs for the design services is $158,000. Design for this project is expected to take six months.

RECOMMENDATION:

Administration recommends approval.

Attachments
Resolution - Farmers Branch Creek Dredging Project