Stormwater Runoff Best Management Practices For Marinas: A Guide for Operators

Jay Tanski, New York Sea Grant Extension Program, Cornell Cooperative Extension. Partial funding for this publication was provided by New York State Department of Environmental Conservation Section 319 Program and U.S. Environmental Protection Agency Peconic National stuary Program.

Stormwater Runoff, Hull Maintenance and BMPs – They All Go Together

Stormwater runoff is simply the water from rain and snow melt that flows across the land. This water picks up pollutants left on the land and carries them into wetlands, creeks and bays where they can adversely impact water quality and threaten aquatic habitats. Any development can increase the amount of stormwater runoff, alter natural drainage patterns, and increase the concentration and types of pollutants carried by the runoff.

Even relatively simple practices can help reduce potential pollution from hull maintenance areas.

For marinas, runoff can be a concern particularly in areas used for boat hull maintenance. Due to the materials and compounds used on boats to control fouling and corrosion and for repairs, the wastes generated by sanding, scraping, painting, varnishing and fiberglassing can contain contaminants like metals, solvents and hydrocarbons.

Preparing a vessel for painting can generate paint chips, dust and particles that may contain metals such as copper, zinc, and lead. While some of these metals are relatively harmless on land, if they are not handled properly and allowed to get into the water, they can be toxic to marine organisms even at very low levels. (These levels are so low their harmful concentrations are often measured in terms of parts per billion). Since many contaminants tend to attach themselves to solid particles, even soil and dirt in hull maintenance areas can pick up potentially harmful materials. In addition to adversely affecting marine life, material washed into the water from hull maintenance areas can also contaminate sediments in the marina basin, posing problems for dredging and the disposal of dredged material. Finally, allowing pollutants to seep into the ground can eventually contaminate the site itself, posing problems if the marina is ever to be sold.

So, it is not hard to see why it is important to keep a close eye on hull maintenance areas to ensure that the associated wastes do not get into the water. Under the Federal Coastal Nonpoint Source Pollution Control Program, the States are required to develop plans to reduce pollution from stormwater runoff from a variety of sources, including marinas. While marinas are usually not considered a major contributor to water quality problems, existing marinas are being asked to reduce the total amount of solids in runoff from boat maintenance areas by 80 percent as part of this program. The question is how best to do this.

This is where Best Management Practices come in. Put simply, BMPs are really anything a marina operator can do to help prevent or reduce the amount of pollutants coming from his facility. BMPs can involve a wide range of activities including:

  • Building new structures
  • Using new or different equipment or products
  • Changing operating procedures and improving housekeeping practices.
  • Which BMPs are really “best” for a particular facility depends on the marina.

Different Marinas, Different BMPs

When evaluating BMPs for use at a site, it is important to remember all marinas are different and, in some respects, unique. Marinas in different parts of the country can vary tremendously in terms of their average size, services offered and operating characteristics because of differences in boat use, number and size. Even in relatively small geographic areas there can be a great deal of variation in the facilities. In the New York/Long Island metropolitan region, marinas range in size from less than 10 to more than 500 slips. Gross annual revenues range from $14,000 to $15,000,000 with most of the facilities falling towards the lower end of the range.

Obviously, the diversity in size and types of marinas makes it difficult to generalize about BMPs for these facilities. A BMP that works well at one marina might be totally inappropriate for another because of location, site, economic or operational considerations. Each marina must be examined on a site-specific basis to ensure that the most effective and suitable BMPs are selected.

While there is no “one size fits all” set of BMPs for all marinas, there are a number of BMPs often suggested for reducing potential stormwater pollution from hull maintenance areas. Chances are one or more of the BMPs discussed here would be suitable for most facilities.

BMPs are often categorized into two types commonly known as Source-control BMPs and Stormwater-treatment BMPs. Source-control BMPs focus on keeping stormwater from coming into contact with pollutants. Stormwater-treatment BMPs usually involve building structures or installing devices to treat or manage runoff. Source-control BMPs are generally preferred because they usually cost less and can keep most, if not all, of the pollutants out of the water.

Maintenance Area Source-control Bmps

Indoor Maintenance Areas

Moving maintenance and repair work indoors or under roofs where it is not exposed to rainfall is one of the most effective ways to reduce contaminated stormwater runoff. However, it may also be one of the most impractical alternatives for many marinas due to cost, size and space limitations, and zoning restrictions, especially when traditional structures are used.

For marinas with enough room, temporary work enclosures, such as the one shown here, can be a relatively inexpensive way to protect maintenance areas from rain while extending the work season. The enclosures are pre-fabricated structures made of heavy-gauge polypropylene plastic stretched over a tubular metal frame. Although the plastic has a life expectancy of three years, this structure is seven years old and has survived a hurricane and a number of severe “northeaster” storms without major damage.

Indoor work areas should have hard floors to facilitate clean up. Floor drains should be avoided or covered while work is being done.

Temporary enclosures come in various sizes up to 100 feet long, 30 feet wide and 23 feet high.

Usually, enclosures come as a kit with materials and assembly instructions. The marina must supply the labor to actually build the structure. Construction does not usually require special tools or skills, but it can be time consuming.

Because they do not have permanent foundations and are considered temporary or portable, these structures may not require permits or zoning approvals in some locations and may also be exempt from capital improvement taxes. Check with your local building department regarding the laws and regulations in your area.

Moving certain types of work, like painting, indoors or into enclosed areas may require the use of special ventilation equipment, protective clothing and respirators, and safety equipment to meet Occupational Safety and Health Administration, Clean Air Act, and local fire safety requirements and regulations.

Buildings capable of handling boats can cost over $60 per square foot to construct in the New York area, not including land costs. (All cost estimates in this document are given in 1997 dollars unless otherwise noted.) Unless a building is already available, it is not feasible for most marinas to build a structure solely for maintenance activities. Typical costs for temporary work enclosures run between $3 to $5 per square foot for materials. This does not include labor.

Outdoor Maintenance Areas

Usually, it is not practical for marinas to do all maintenance work under a roof. If work has to be done outdoors, it should be done over dry land in specially designated areas designed for that purpose. These areas should be clearly marked with signs. Customers (and staff) should be discouraged from performing maintenance work outside these areas.

Indoor work areas should have hard floors to facilitate clean up. Floor drains should be avoided or covered while work is being done.

Temporary enclosures come in various sizes up to 100 feet long, 30 feet wide and 23 feet high.

Usually, enclosures come as a kit with materials and assembly instructions. The marina must supply the labor to actually build the structure. Construction does not usually require special tools or skills, but it can be time consuming.

Because they do not have permanent foundations and are considered temporary or portable, these structures may not require permits or zoning approvals in some locations and may also be exempt from capital improvement taxes. Check with your local building department regarding the laws and regulations in your area.

Moving certain types of work, like painting, indoors or into enclosed areas may require the use of special ventilation equipment, protective clothing and respirators, and safety equipment to meet Occupational Safety and Health Administration, Clean Air Act, and local fire safety requirements and regulations.

Buildings capable of handling boats can cost over $60 per square foot to construct in the New York area, not including land costs. (All cost estimates in this document are given in 1997 dollars unless otherwise noted.) Unless a building is already available, it is not feasible for most marinas to build a structure solely for maintenance activities. Typical costs for temporary work enclosures run between $3 to $5 per square foot for materials. This does not include labor.

Work Outside of Designated Hull Maintenance Areas

In some marinas, it may not be possible to have a designated work area for all hull maintenance activities due to space limitations, time constraints, or cost. If work has to be done outside a designated area, precautions should be taken to contain wastes and debris and prevent them from entering the water.

Tarps used to contain paint chips and dust from hull maintenance activities.

In areas that do not have sealed or impervious surfaces, perform all work over tarps or drop clothes. Ideally, tarps should be placed beneath the cradle or boat stand.

If customers are allowed to do maintenance work on their boats, they should be required to clean up the area when done working. Separate, covered, and labeled containers should be provided for waste materials.

When maintenance work has to be done near water, consider the use of additional BMPs such as the innovative paint removal techniques and dustless vacuum sanders described below.

Innovative Paint Removal Techniques

Different paint removal technologies can be used as BMPs to eliminate or, at least, contain paint chips and dust associated with hull preparation activities. Special equipment, products or procedures can also help reduce the amount of waste material generated and ensure it does not get into the environment.

New abrasive hull blasting technologies utilize a process to reclaim and reuse media made of plastic. In this procedure, the boat must be completely enclosed to trap the media and paint waste. The collected mixture is fed into specialized equipment (located in the truck in the photograph) which through a sifting process separates most of the paint dust and chips from the media, which can then be reused. In addition to containing paint dust and chips, this process can significantly reduce the amount of material that has to be disposed of when stripping a hull. For example, the plastic media stripping of a 19-foot boat produced a total of 200 pounds of waste and media. The equipment recovered 185 pounds reusable media (containing a small amount of paint), leaving only 15 pounds of paint for disposal.

Specialized equipment and training is required for plastic media blasting. In some areas companies have mobile equipment and will perform this service on site for a set fee.

Containment of dust and other debris and recovery of the media can considerably reduce clean up and disposal costs.

Since the media can not remove anything harder than itself, these techniques may not be effective for preparing all surfaces. For instance, plastic media may not remove corrosion or barnacles from props, shafts, or rudders. However, it will remove paint without damaging sound gel coat, rubber, chrome or glass surfaces.

Some softer media may not work well on very durable, pliable paints (like coal tar epoxies). Paint around edges may have to be removed by hand. Sanding is usually required before painting a blasted hull.

Care should be taken when blasting boats that have damaged or blistered gel coats since blasting may open blisters or voids that have to be filled before painting. Even sound gel coat may contain small voids that may have to be filled after blasting.

Equipment costs for a blasting system that incorporates media recovery and reclamation start at $25,000, not including training or the media. In New York, contractors with their own mobile equipment will blast hulls with plastic media on site for approximately $17 to $18 per foot, where length is calculated as the length of the boat at the waterline plus one-half the beam. (Approximate cost for blasting a “typical” 30-foot power boat is about $630.) Discounts may be available for volume work.

Chemical paint stripper and covering cloth applied to boat hull

Chemical paint strippers can actually eliminate paint chips and dust associated with sanding, scraping and blasting. There are now less toxic and less hazardous alternatives to strippers that use methylene chloride and other organic solvents. New products are non-chlorinated, biodegradable, have low volatility and are not listed as hazardous. Some of the more environmentally-sensitive strippers may be water based and use less toxic materials (look for dibastic esters, semi-aqueous terpene-based products, detergents and C9 to C12-based hydrocarbon strippers). While the new strippers themselves may be considered non-hazardous, metals and chemicals from the paint they remove may be hazardous, so all residue and wash water must be collected and disposed of properly.

Environmentally-sensitive paint strippers are usually made without toxic or caustic chemicals, so they do not burn skin and will not release harmful fumes like some of the more aggressive chemical strippers. This can reduce or eliminate the need for special ventilation equipment.

The more environmentally-friendly strippers may require more experience and expertise to apply correctly, as well as more time to work effectively. Some may have to remain on the hull for 2 to 24 hours depending on the condition of the hull and air temperature. Lower temperatures require longer times, and some products do not work well below 32°F.

When stripping, place plastic around and under the work area to catch any drips. Some products come with a special paper placed over the stripper after it has been applied that helps contain the chemicals and dissolved paint.

Strippers may not work on all paints, such as 2-part epoxies or chlorinated rubbers. Check with the manufacturer for specific applications.

Machine used to pressure wash and collect washwater in one step from chemically stripped hull.

Stripping residue and washdown water may be contaminated by paint and must be collected and disposed of properly, possibly as a hazardous waste. Special machines that pressure wash the hull and collect the washwater in a one-step process are available for this purpose. It is estimated that a 30-foot boat would generate approximately 30 gallons of waste, including washdown water.

Costs will vary depending on product used, conditions, and layers of paint to be removed. Non-toxic, water-based strippers can cost $40 to $60 per gallon. According to one manufacturer, a gallon of their product will cover an average of 50 square feet of hull so the estimated cost of materials is one dollar per square foot. A 30-foot boat may require five to six gallons. The manufacturer also estimated disposal cost for the residue to be about $30 per boat depending on size. Complete pressure washing/vacuum collection systems cost $5,000 but costs can be reduced if the marina has an existing pressure washer and/or vacuum system.

Dustless Vacuum Sanders

Dustless vacuum sanders are sanders (or grinders) attached to a vacuum system that starts automatically when the sander is turned on. These units can trap up to 98 percent of the dust generated by hull sanding, making them particularly suitable for situations where work must be done near the water.

By containing dust, vacuum sanders keep work areas and workers clean, saving time and money in clean up.

To recover costs, some marinas rent the sanders to customers for use on their own boats for fees ranging up to $15 per hour. Advertising and training is necessary to encourage use.

Studies indicate that sanders may collect an average of two ounces of dust per foot of boat sanded (3.75 pounds for a 30-foot boat). This material must be collected and disposed of properly.

The cost of vacuum sanders varies depending on size and features. Typical costs range between $1,100 and $1,400.