Marina Dredging Requires Complex Planning & Management

Marina Dredging Seminar Covers New Ground at the Brisbane Marina in San Francisco Bay

Dredging is one of those projects that nearly every coastal marina and many inland marinas will inevitably face during their lifespan. Whether the need is a relatively simple ‘maintenance’ suction dredge or a more extensive clamshell dredge, the process is complex, time consuming, and costly. Understanding the intricacies, from evaluation, planning, permitting, to implementation, is critical for managing and minimizing the negative impacts.

The west coast Marine Recreation Association recently sponsored a new Regional Training Seminar covering Marina Dredging: Planning, Permitting, and Management, at the Brisbane Marina in San Francisco Bay. The seminar was attended by twenty-five marina management professionals from a variety of coastal and inland harbors.

The seminar training was presented by a team from the engineering and environmental firm of Anchor QEA, in conjunction with the current dredging of the Brisbane Marina basin, and covered the critical planning, permitting, and project management issues involved in a typical dredging project.

Dredging periods vary from one region to another in the United States, and are particularly tight within California. In the San Francisco Bay, dredging is restricted to the months of June through November due to fish and wildlife, and other environmental concerns. Time constraints vary in other regions, but are typically also very short requiring projects to be very precisely timed, planned, and implemented.The Brisbane Marina dredging is now in the second year of a two-phase project designed to deepen both the marina basin and harbor entrance. Anchor QEA is managing the ongoing work with Dutra Dredging contracted to remove 180,000 cubic yards of material from the harbor. The marina entrance and deep-water slips were dredged last year, leaving about 50% of the work still to be completed this season. The bulk of the work is being done with clamshell excavation equipment loading the dredge material onto dump barges. The material is then being disposed of at the San Francisco Bay, Alcatraz disposal site.

Dr. Joshua Burnam opened the seminar with a presentation on ‘Planning, Design, and Construction of Marina Dredging’. Josh is a Partner, and Principal Environmental Planner at Anchor QEA, specializing in planning, permitting, and construction management of dredging and other waterfront projects. “Dredging is a complicated, economy of scale process,” he stated. “Planning needs to begin at least eighteen months ahead of the anticipated start date.”

Dr. Burnam laid out a typical project timetable, beginning with an in-depth evaluation of the dredging needs, and other construction that might be included in a broader scope of work. Detailed planning and permitting work should be completed twelve to nine months before dredging, including a comprehensive sampling and materials analysis program. Final project design and construction bid documents should be done six months ahead of the anticipated start date with all permitting and surveys of the site done at least a month before mobilization. At that point the actual project management takes over.

Josh also covered the regulations and permits required for dredging and marine construction projects, including interaction with the Army Corps of Engineers, Section 10 Rivers and Harbors Act, Section 404 Clean Water Act requirements, and considerations for upland versus ocean disposal of dredge materials. The myriad of other permitting and regulatory agencies were reviewed, including federal and state EPA, fish and wildlife agencies, Regional Water Quality Boards, California Coastal Commission, and San Francisco Bay Conservation and Development Commission. The benefits of coordinating agencies in some regions, such as the SF Bay Dredge Material Management Office (DMMO), to help consolidate the permitting process was also reviewed.

One of the more important aspects of any dredging process is the disposal site, which can significantly influence the type of dredging process to be used, and heavily impact project costs. Dr. Burnam discussed the Four-Tiered Testing and Evaluation process required by the various state and federal agencies to determine appropriate disposal options for dredged materials, and of course the major cost impacts.

Jaclyn Gnusti, P.E., continued the seminar with a presentation on ‘Preliminary Design Considerations’, reviewing the various types and costs of different dredging equipment and material disposal options. Properly surveying and mapping the dredging site, and identifying various bottom materials and potential ‘debris’ in order to accurately budget the project is critical. Old pilings, concrete rip-rap, and other sunken debris can significantly impact both disposal and project time costs. Other key planning and design challenges were also reviewed, including staging considerations, moving vessels, dock and marina access during construction times, and other impacts on marina tenants and visitors.

The seminar was completed by Michael Whelan, P.E., who reviewed the all-important aspects of the bid and contracting process, including project management and monitoring concerns, progress surveys and reports, sediment and turbidity management, and final completion and payment considerations. Accurately surveying the harbor basin before and during the project is critical for measuring the amount of materials removed, the final results achieved, and the ultimate payment to the contractor.

At the end of the morning session, participants walked out on the Brisbane Marina docks to watch the ongoing dredge work by Dutra. Observing the actual process of the clamshell excavation, working closely under and around the marina docks, was an eye-opening experience. All of the attendees felt that the information they gained was very important, and would help them do a better job planning and implementing future dredging and marine construction projects.

Mariann Timms, MRA Operations Administrator stated, “Our Regional Training Seminars have been very popular this summer, and we filled up eight sessions covering electrical and dredging training across the state.” The MRA will continue their marine education and training at the 45th Annual MRA Educational Conference & Trade Show, this October 24 – 26 at the Hilton Torrey Pines Resort in La Jolla, California.

J. Mills is a freelance writer, Outdoor Recreation & Marina Operations Consultant, and a licensed General Engineering Contractor and Realtor. He is also Editor at the Bay & Delta Yachtsman magazine, and welcomes your comments and questions at https://linkedin.com/in/jamesmcv.