Section 2: Designing Marina Facilities and Structures

When marinas are designed with consideration of land and water quality in mind, they can be an asset instead of a detriment to the ecosystem. They can allow for quiet, sheltered waters. A marina can assist in replacing natural habitat that allows for feeding and spawning. Subsequent pollution prevention measures taken by the marina will help maintain or even improve water and habitat quality, leading to a more aesthetically pleasing marina.

Maintaining water quality within a marina basin is very important. The water quality and biological health of marinas depends largely on how well water circulates and is flushed within and through the basin. If a marina is not properly designed, pollutants will build up in the water or sediments. Excess dredging to create deeper water can slow flows and diminish re-oxygenation of waters in the marina basin.

The final design of a marina should be a compromise of marina capacity, services, and access, while minimizing environmental impacts, dredging requirements, protective structures, and other site development costs.

Learning Objectives

By the end of this section, you should be able to:

  • Pursue a marina design that capitalizes on your site’s natural features.
  • Understand the importance of water circulation and the influence of your marina design.
  • Identify design and construction practices that minimize environmental impact.
  • List a range of shoreline protection options and select the “softest” option that meets needs.
  • Incorporate plans to conserve resources (e.g., water conservation, recycling).

Best Management Practices

Obtain Appropriate Permits

  • Obtain the proper federal and state permits for all past activity and pledge that all permits will be obtained for future marina construction and dredging. check box for Regional Best Management Practice Regional Best Management Practice
  • Consult your state regarding the definition and regulations related to public trust bottomlands and tributaries. check box for Regional Best Management PracticeRegional Best Management Practice
  • Obtain erosion control permits for all past construction and pledge that permits will be obtained for all future marina construction. check box for Regional Best Management Practice

Use Open Design Fixed or Floating Piers to Enhance Water Circulation

Marinas must be carefully designed. Incorrectly designed structures can amplify wave action, which exacerbates erosion, creates excessive shoaling, and interrupts or restricts circulation — all of which can increase unfavorable environments.

While being mindful of the need for pier or dock systems to provide access during routine operations and under emergency circumstances (e.g., evacuation preceding or during a storm), piers and other structures should be placed to enhance, rather than to obstruct, water circulation.

  • Select a marina design that enhances water circulation and minimizes the need for dredging. Regional Best Management Practice
  • Select an open design for new or expanding marinas. Open marina designs have little or no manmade or natural barriers to restrict the exchange of ambient water and water within the marina area. Install wave attenuators (if permitted) to reduce the force of incoming water, if protection is necessary and conditions are appropriate. Wave attenuator use is limited to bodies of water with fetch restricted to roughly 3- 5 miles or less. Wave attenuators do not restrict water exchange, nor do they interfere with bottom ecology or aesthetic view. They are easily removed and do not significantly interfere with fish migration and shoreline processes.
  • Design new or expanding marinas with as few segments as possible to promote circulation within the basin (refer to figure below). The fewer the segments, the better the circulation.
  • Use a mechanical aeration system (water circulating system) to aerate areas with poor flow. Aeration systems need to be routinely inspected to avoid becoming encrusted with zebra and quagga mussels and other organisms. Submersible pumps may be protected with materials that resist attachment (e.g., brass and galvanized steel). This also holds true for air lines if a bubbling system is employed. Circulators can also minimize icing during winter.
  • Advantages of floating docks systems include the adaptation to fluctuating water levels; the capability of removing them in the winter to avoid ice damage; and zebra and quagga mussels can be easily removed when the docks are stored on land.

“In January 2010 [our] marina changed over from fixed piers to floating piers.  With the improved technology, floating piers are the best way to go.

We went with removable concrete decking panels 2’x3′. This allows you to be able to remove them to do any type of repair. A good example of this benefit was the spring of 2011 after the first winter of the docks being installed, we discovered a broken waste pump-out pipe. We were able to remove several panels to gain access to the leak and repair the pipe and install a valve to drain excess water in a lower area.” – A Wisconsin marina harbor master, 2013.

Figure: Example of marina designs (Source: U.S. EPA 2001).

For more information on marina design, see: Marina Flushing – Siting and Design (EPA Management Measure) and the American Society of Civil Engineers’ (ASCE) Manual and Reports on Engineering Practice, No. 50: Planning and Design Guidelines for Small Craft Harbors, Third Edition.

Additional Marina Design Considerations

  • If you are expanding a marina, consolidate new development and expansion within the present footprint of the facility (land and water). Expanding into the upland areas rather than building out onto the bottomland is preferred. This avoids the loss of access to public trust waters and bottomland.
  • Damage from ice can potentially cause oil and gas spills and the deposition of debris. Identify areas prone to ice flows and come up with construction or management solutions.
  • Locate fueling stations in areas protected from waves and easily accessible by boat without entering or passing through the main berthing area. check box for Regional Best Management Practice

“When we were designing the new marina we considered installing a pump-out system where we could pump-out tenants’ holding tanks while their boat was in their slip. [One supplier] offered a system that provided a recessed hydrant on the dock that allows us to pump out four boats for every hydrant. This amenity really makes our tenants happy!” – A Wisconsin marina harbor master, 2013.

Use Environmentally Neutral Materials

  • For new pilings and other structures that are in or near the water, use materials that will not leach hazardous chemicals into the water and which will not break down (e.g., reinforced concrete, coated steel, recycled plastic, vinyl sheet piling, or plastic reinforced with fiberglass).

“If you are converting your fixed docks to floating docks and have sound pilings, you should seriously consider reusing the old pilings. [Our builder] was able to construct our floating piers using most of our outer pilings to anchor our docks. This ended up saving us thousands of dollars.” – A Wisconsin marina harbor master, 2013.

  • Contain shavings when field cutting plastic pilings and timbers.
  • Avoid using wood treated with creosote or chromated copper arsenate (CCA) for pilings and similar structures that are in or near the water. check box for Regional Best Management Practice
  • Avoid use of asphalt below the ordinary high-water mark. check box for Regional Best Management Practice
  • Avoid use of coal tar sealants on paved areas; they are a source of harmful contaminants (PAHs) that can impact the health of humans, fish, and wildlife.
  • Use naturally durable timbers conservatively. Black locust, cedar, chestnut, and white oak are naturally durable but expensive and may be hard to find.
  • Avoid exotic timbers. Some tropical trees, such as greenheart and bongossi, are also naturally durable, but their harvest is harmful to tropical forests.
  • Purchase floatable foams that have been coated or encapsulated in plastic or wood. As these floats age, degraded foam is contained by the covering. Unprotected floats may become inhabited by muskrats and other mammals, seriously reducing the flotation capability of the dockage.
  • When designing and constructing marina buildings and related facilities, consider incorporating “green building” practices. For more information, see: LEED guidelines.
  • Maintain structures using Clean Marina principles, i.e., scrape, sand, and paint structures according the same management principles as for vessels (see Boat Maintenance Unit), move floating structures to prescribed areas for scraping, painting, and major repairs. check box for Regional Best Management Practice

Other design considerations include safety and navigation in the marina basin and adequate parking. For more information on these issues and others with regard to designing marinas, see: American Society of Civil Engineers’ (ASCE) Manual and Reports on Engineering Practice, No. 50: Planning and Design Guidelines for Small Craft Harbors, Third Edition.

Limit Shaded Areas Over the Water

  • Submerged aquatic vegetation and near-shore, bottom-dwelling organisms require sunlight. In order to provide them with as much sunlight as possible, limit the number of completely covered slips.
  • Choose docking systems that minimize light blockage.

Minimize the Need for Dredging

New marinas must be located in areas where deep water can be reached with a minimum of excavation, filling, and dredging. Existing marinas that require maintenance dredging more frequently than once every four years should investigate practical options to increase circulation or reduce sediment accumulation. Possibilities include:

  • Extending piers and docks into naturally deep waters. check box for Regional Best Management Practice
  • Locating slips for deep draft boats in naturally deep water. check box for Regional Best Management Practice
  • Dredging channels to follow the course of the natural channel.
  • Providing dry storage for smaller boats.

Minimize the Impacts of Dredging

The majority of marina development and expansion projects along the Great Lakes, including dredging, will require a permit from the U.S. Army Corps (USACE) of Engineers and the responsible state agency. To streamline this process, “joint permits” are often offered. For more information, see the State Laws page for your state.

Dredging has the potential to impact fish spawning and juvenile fish survival. Direct impacts to the area dredged include destruction of spawning habitat, destruction of fish eggs, and mortality of fish within the dredging area due to removal of bottom substrates and resulting high levels of suspended silt. Currents can move silt particles suspended during dredging away from the site and deposit them in spawning or juvenile fish habitats some distance away.

Sediment testing may not be required for every dredging permit application. In some cases the state agency may require dredge material characterization. Contact your state agency early in the planning for dredging to see what is required. If required, sediment testing data need to be submitted with the permit application. The testing data will determine the appropriate disposal site and impose conditions on the site such as a clean soil cap, fencing, etc.

The dredging permit will require actions to minimize the subsequent impacts.

  • Avoid dredging during critical migration or spawning periods. Federal and state fisheries and wildlife officials have long recommended the implementation of timing restrictions on dredging projects during critical migration or spawning periods. Contact your state agency to determine when these periods are. The remaining time windows allow the necessary dredging to be accomplished without severely affecting valuable fish and wildlife resources of the Great Lakes and inland waters. check box for Regional Best Management Practice
  • Avoid water bird nesting areas and historic waterfowl staging and concentration areas. check box for Regional Best Management Practice
  • Be certain that your dredging contractor selects an appropriate permitted disposal site and containment design based upon the sediment characterization data. The disposal site must have minimal impact on public safety, adjacent properties and the environment. The beneficial usage of dredge materials from marina dredging should always be evaluated. check box for Regional Best Management Practice
  • Use dredging methods, like hydraulic dredging or the use of low-turbidity, mechanical dredging buckets, which minimize environmental impacts.
  • Always use silt curtains to contain suspended sediments.

Employ Nonstructural Shore Erosion Control Measures

The booklet, Along the Shore, includes information about shoreline management activities, ordinary high water mark, Michigan laws, and the Public Trust Doctrine.

Waterways are often lined by structures designed to stabilize shorelines, protect property from flooding and erosion, or to accommodate commercial navigation or industry. These structures have historically been made of wood or metal pilings, rock, or reinforced concrete. Many Great Lakes shorelines are marked by seawalls, revetments, breakwaters, groins, and jetties. Over the years, such “hard” engineering has been recognized to have its own environmental consequences.

While traditional hard structures continue to be installed or maintained around the Great Lakes, rising awareness of their detrimental effects are leading to a call for “soft” engineering to protect the shore.

Soft shorelines utilize ecological principles and practices to reduce erosion and achieve the stabilization and safety of shorelines, while enhancing habitat, improving aesthetics, and often saving money.

Soft shorelines are characterized by the use of vegetation and other materials to soften where land meets water. Hard shoreline structures tend to take up less space and may have an advantage in environments that are prone to erosion. However, mandatory “no wake” zones in and around marinas will allow soft shorelines to be more successful.

A coastal engineering analysis will be required to determine whether a hard structural solution or soft, bioenegineered approach can be used, as well as the nature of the vegetation or armoring type needed to create the necessary protection. Ideally, the protection method used will mimic or be sympathetic to the existing environment.

  • Consult a site engineer. When developing marina plans, consider consulting a coastal or water resource engineer to enhance or maintain proper water movement, including consideration of impact on adjacent properties. See Section 1: Site Selection for more information on water movement. check box for Regional Best Management Practice
  • To preserve habitat and natural processes, use soft shorelines where feasible. Focus erosion control measures on nonstructural applications. Where structural practices are required, chose the least intrusive option.
    • Employ nonstructural shore erosion control measures. Nonstructural measures, such as beach nourishment, wetlands creation, and other methods that encourage the preservation of the natural environment are the preferred methods of shore erosion control.
      • Beach nourishment entails the introduction of replacement material to restore waterfronts degraded by erosion. If using this option, take care to avoid transfer of undesired elements in the new material (e.g., invasive species, pollutants) and also when introducing vegetation to stabilize the new material. Beach nourishment is appropriate only if a beach was once present and if there is still room to rebuild the beach. The restored beach will likely have a larger footprint than a hard solution, so there is a tradeoff of physically changing a larger part of the environment to create a beach — versus building something with a smaller footprint and preserving the remaining natural areas instead. A beach environment would also not be the same environment as a wetland or mudflat, so the local biology should dictate the solution type.
      • Because soft engineering uses living structures, which tend to stabilize with time, soft engineering of shorelines is typically less costly to install and maintain than hard engineering.
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    • If nonstructural measures alone are not sufficient to control erosion, use structural controls to stabilize and ensure the long-term viability of the nonstructural controls. As a last resort, use structural controls in this order of preference: shoreline revetments (riprap) and bulkheads (vertical walls, concrete, or steel sheet pile). The structure of riprap armor may serve as forms of habitat and, in some circumstances, can allow vegetation to re-establish between the armor pieces. It is also composed of natural and native material. Vertical walls typically stymy habitat formation and the material is not always compatible with the existing environment.
    • A combination of soft and hard solutions may be possible (e.g., intersperse plantings with riprap). Local organizations may provide additional guidance on natural shoreline landscaping and bioengineered erosion control techniques. For example, the Michigan Natural Shoreline Partnership (MNSP) trains and certifies professional waterfront contractors.
    • Minimize the adverse effects of erosion control projects on adjacent properties, navigation, threatened or endangered species, and significant historic or archaeological resources.
  • If you have erosion-prone areas, designate a “no wake” or “no boating” zone to reduce sediment re-suspension from prop wash or destruction of shallow water habitat. Regional Best Management Practice
  • Consult with local and state permitting authorities for sediment control requirements and use soil erosion control practices during construction. Regional Best Management Practice

Additional resources on shoreline management:

Conserve Water

It sometimes seems like water is a limitless resource, but the fresh water that is available for use is limited. Water is constantly being recycled through the earth’s water cycle. However, water is often used faster than it can be naturally replenished. Conserving water and other natural resources saves energy, helps the environment (by taking some of the stress off the resource), and saves money.

  • Equip all freshwater hoses with automatic shutoff nozzles.
  • Fix any dockside faucet and hose leaks and drips. Regional Best Management Practice
  • Install “low-flow” faucets, toilets and shower heads at public marina toilet facilities. Regional Best Management Practice
  • Install automatic faucets and toilet fixtures.

Anticipate Recycling Needs

State and local laws may require provisions for recycling of certain waste materials.

  • Anticipate needs for collection bins and pick-up services when designing a marina.

Next: Unit Review