SECTION 3: Nonpoint Source Pollution Control

3-1

SECTION 3: NONPOINT SOURCE POLLUTION CONTROL AND

WATERBODY CHARACTERISTICS

Understanding Management Measures and

Practices

Management measures and practices are implemented at marinas primarily to control nonpoint

source pollution, which in turn protects water

resources and terrestrial and aquatic habitat,

enhances the aesthetic appeal of the marina, and

protects the marina and the people using it from

toxic and harmful substances. The focus of this

guidance is on management measures and

practices that mitigate the generation of pollutants

(using pollution prevention practices) and the

delivery of runoff or nonpoint source pollutants

(using source reduction practices) to our nation’s

coastal and fresh waters.

Management measures are defined as

economically achievable measures for

the control of the addition of pollutants

from existing and new categories and

classes of nonpoint sources of pollution, which reflect the greatest degree

of pollutant reduction achievable

through the application of the best

available nonpoint source control

practices, technologies, processes,

siting criteria, operating methods, and

other alternatives.

Marinas and recreational boating management

measures contain general management guidelines

to prevent or minimize nonpoint source pollution.

Individual management practices are not included

as part of the statement of the management

measures, and states have considerable flexibility

in determining how they will achieve the management measures.

Best management practices, or BMPs, are used

to fulfill management measures. There are two

basic types of management practices—pollution

prevention and source reduction. Pollution prevention practices are practices implemented to

prevent the creation or release of pollution into the

environment. An example is a vacuum sander that

gathers sanding dust before it even has a chance

to fall to the ground. Using a nontoxic cleanser in

place of a toxic one is another example of pollution prevention. Source reduction controls are

practices implemented to gather pollutants that

have been released before they can reach the

water. They include practices that filter, screen,

trap, contain, absorb, chemically neutralize, or

divert pollutants before they reach a waterbody or

Section 3 Contents

Understanding Management Measures and Practices .................................................3-1

How Management Practices Work to Prevent Nonpoint Source Pollution ................3-2

Management Practice Systems ........................................................................................3-4

Site-Specific Design of Management Practices ............................................................3-4

Important Characteristics of Marina Environments from a Pollution

Perspective ....................................................................................................................3-5

General Factors Common to All Waterbodies ............................................................3-5

Lakes and Reservoirs ..................................................................................................3-5

Rivers .............................................................................................................................3-6

Estuaries ........................................................................................................................3-6

Coastal Environments ..................................................................................................3-7

Boating on Inland Waters ..................................................................................................3-7

Boating Access ..................................................................................................................3-8
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National Management Measures Guidance

ground water. An oil/water separator in a storm

drain is an example. A tarp under a boat during

hull maintenance, with follow-up disposal of all

collected debris in a trash receptacle, is another

example of source reduction.

Management measures and practices can also be

either structural (e.g., used oil collection containers, multiple openings to a marina basin) or

managerial (e.g., pollution control agreements in

slip leases, marina policies regarding where boat

hull maintenance can be done on the marina

property and who is allowed to do it). Individual

management practices are not usually sufficient

for solving water quality problems but are used in

combination to control the diverse potential

sources of pollution at marinas. For example,

placement of absorbent pads in bilges is a good

means to control the release of petroleum-based

pollutants, but without storm water runoff controls

in parking lots and air/fuel separators to control

spillage during refueling, petroleum hydrocarbon

pollution in the marina basin is likely.

Management practices are best selected, designed, implemented, and maintained in accordance with site-specific considerations to ensure

that the practices function together properly to

achieve overall pollution management goals. For

example, a grassed drainage swale designed to

handle only the quantity of water expected to fall

on a parking lot during a design storm will not

effectively control pollution if the grassed drainage swale receives runoff from non-marina

upland areas as well. When more than one

management practice is used to control a type of

pollutant from individual or multiple sources, the

individual practices will work as a system more

effectively if the design standards and specifications of the individual practices are compatible.

Additional effectiveness might be achieved if

BMPs for a site are selected within the context of

an overall watershed protection program. Further

information can be found at EPA’s watershed

protection web site, http://www.epa.gov/owow/

watershed.

EPA’s management measures for marinas and

recreational boating are described in Section 4.

How Management Measures and Practices

Work to Prevent Nonpoint Source Pollution

Nonpoint source pollution control management

measures and practices are devised to prevent

and reduce the introduction of pollutants generated by marina-related activities to the marina

basin. Controlling the entry of pollutants into the

marina basin helps protect water quality, control

aquatic weeds, reduce odors that result from

decaying matter, ensure a more attractive and

healthy shoreline, maintain water clarity, and allow

for the natural ecological processes of the marina

basin and surrounding waters to maintain the

basin without the need for expensive chemical or

mechanical treatments.

Management measures are recommended to

control the delivery of nonpoint source pollutants

to receiving waters by

• Minimizing pollutants released to the environment during an activity (pollution prevention).

• Preventing the transport and delivery of

pollutants by reducing runoff and thus the

amount of pollutant transported (source

reduction).

• Treating runoff pollution before it is released

into surface or ground waters (source reduction).

Management practices are used to control

pollutants generated by specific activities. For

example, pumpouts, dump stations, and/or

restrooms are installed to discourage dumping

sewage into waterways and thus to reduce the

release of organic materials and pathogens into

the water.

Implementing management measures and practices also provides secondary benefits. For

example, use of a vacuum-based (often referred

to as “dustless”) sanding system prevents paint,

wood, and fiberglass dust from being blown about

and potentially ending up in marina basin waters.

It also improves working conditions, protects the

health of employees, and reduces post-sanding

clean-up work so workers can be more productive. Another example of a management practice

that provides environmental benefits beyond those

linked to water quality is a grassed drainage swale
SECTION 3: Nonpoint Source Pollution Control

3-3

surrounding a marina basin. As a runoff pollution

control practice, it reduces nutrient and sediment

delivery to the basin. It also provides an aesthetic

buffer along the water’s edge and natural habitat

for aquatic plants and animals.

Nitrogen and phosphorus, in both dissolved

organic and inorganic forms, are the two principal

nutrients that promote plant and algal growth. In

general, nitrogen is the limiting nutrient for plant

growth (the nutrient whose abundance determines

rates of plant growth) in marine ecosystems, and

phosphorus is the limiting nutrient in freshwater

ecosystems. Both nitrogen and phosphorus can

limit plant growth in some estuarine systems,

where freshwater and marine ecosystems

converge, and both are necessary for the production of phytoplankton, free-floating microscopic

algae, and macrophytes (larger floating and rooted

plants). When the limiting nutrient is overabundant, phytoplankton, algae, and macrophytes can

grow excessively, causing a decrease in water

clarity, production of unsightly surface scum, and

clogged waterways. All of these conditions are

detrimental to marina operations for aesthetic

reasons. They are also detrimental for operational

reasons: excessive macrophytes can hinder boat

passage and entangle propellers and pipelines. As

these plants die, their decomposition in the marina

basin consumes dissolved oxygen and degrades

water quality. In extreme cases, anaerobic, foulsmelling water might result.

For these reasons, controlling the entry of nutrients into the marina basin makes good managerial

sense. The marina will be aesthetically more

appealing and operationally more functional, and

maintenance costs will be kept down by not

having to harvest overgrowths of aquatic plants.

Sources of nitrogen and phosphorus at a marina

include detergents that contain phosphorus,

sewage from boat heads or on-site septic systems, fertilizers used on marina grounds, pet and

wildlife waste, and waste from fish cleaning.

The introduction of pathogens into a marina basin

due to inadequate sanitation practices is a legitimate cause for concern by marina managers. If

the water in a marina basin has elevated levels of

fecal coliform bacteria or is contaminated with

viruses, marina patrons could be in danger of

contracting illness. Insistence that marina patrons

use pumpout stations or have a properly operating

Type I or II marine sanitation device (MSD) on

their vessel can protect the patrons from the

dangers of poor sanitation and the marina owner

from lawsuits that could result from such incidents.

The types of MSDs are described in Table 3-1.

Untreated sewage, pet waste, discarded fish

parts, and all forms of litter can add polluting

organic matter and debris to a marina basin’s

water, creating an aesthetically and biologically

undesirable environment. Excessive organic

matter in a marina basin leads to lowered dissolved oxygen levels. It also makes water murky.

Water clarity is reduced further from other

activities that stir sediment and particles of

decomposing organic debris up from the bottom.

Litter like paper and styrofoam cups, plastic bags

and soda can holders, fishing lines or nets, and

discarded materials from boat maintenance

activities creates an unsightly marina basin. It is

also a threat to fish, waterfowl, and shorebirds,

which can become entangled in plastics or might

eat debris mistaken for food and die as a result.

Harmful or toxic compounds in a marina basin

create conditions that not only are dangerous to

the health of people and animals but also can be

aesthetically unpleasant and expensive to correct.

Petroleum compounds can be toxic to aquatic

habitat and a nuisance for marina patrons. Oil,

gasoline, and materials that contain these compounds (such as discarded oily rags, bilge pads,

and dirty bilge water) are pollutants that detract

from the beauty of the marina setting by leaving

an unsightly surface sheen. In addition, the

discharge of any petroleum product in a sufficient

quantity to cause a surface sheen is a violation of

federal law and is punishable by the imposition of

substantial fines and penalties. These compounds

foul boats, docks, and anything else that comes

into contact with them. Fish gills and the feathers

of waterfowl are fouled by these substances,

jeopardizing the animals’ health, and plant leaves

can become coated, preventing or reducing the

plants’ ability to photosynthesize.

All of these potential sources of pollution to

marina basins and the undesirable conditions they

cause for marina patrons and owners point out the

importance of establishing controls on how wastes
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National Management Measures Guidance

are disposed of, the use of pumpouts, where

storm water drains, and where boat maintenance

is allowed to occur. Good pollution control can

leave marina basin waters as healthy an environment for people, fish, aquatic plants, and other

aquatic organisms as any other part of a

waterbody.

Management Practice Systems

Water quality problems can’t usually be solved

with one management practice because single

practices cannot provide the full range and extent

of control needed to limit the entry of pollutants

from numerous sources. Multiple management

measures or practices can be combined to build

management practice systems that address the

pollutant control needs associated with pollutant

generation from more than one source. For

example, controlling petroleum hydrocarbon

pollution is an objective of four marina management measures (storm water runoff, fueling

station design, liquid material, and petroleum

control). A single management practice cannot

adequately control petroleum hydrocarbon

pollution because one management practice can

usually address pollution from only a single

source. Separate management practices are

necessary to control pollution from other sources.

For instance, a grassed drainage swale can

control petroleum hydrocarbon pollution from

surface runoff, air/fuel separators can control it

from boat fuel tanks, berms are helpful (and might

be required) at liquid material storage areas, and

bilge pads are effective in boat bilges. If any one

of these sources is overlooked or inadequately

addressed, the overall goal of controlling petroleum hydrocarbon pollution in the marina basin

might not be attained.

Site-Specific Design of Management

Practices

There is no single, ideal management practice for

controlling a pollutant or class of pollutants in all

situations. Rather, management practices should

be chosen and designed based on the types of

pollutants causing problems, sources of the

pollutants, causes of pollution at the marina,

climate, type of waterbody, existing water quality,

habitats in and around the marina basin, pollution

reduction goals, experience of the system designers, and willingness and ability of the marina

owner to implement and maintain the practices.

The relative importance of these and other factors

varies depending on other considerations such as

MSD TYPES

Type I

(Vessel size = <65 ft)

A flow-through MSD in which sewage is filtered though an on-board

treatment system and then directly discharged. Required to produce an

effluent with a fecal coliform bacteria count  1,000/100 mL and no visible

floating solids (40 CFR 140.3). Rely on maceration and disinfection for

treatment of sanitary waste.

Type II

(Vessel size = >65 ft)

A flow-through device larger than a Type I MSD. Required to produce an

effluent with a fecal coliform bacteria count  200/100 mL and suspended

solids  150 mg/L (40 CFR 140.3). A Type II MSD provides more

advanced treatment than a Type I MSD.

Type III

(All vessel sizes)

Device designed to prevent overboard discharge of treated or untreated

sewage. Commonly a called holding tank because the sewage flushed from

the marine head is deposited into a tank containing deodorizers and other

non-treatment chemicals. Contents of the holding tank are stored until

properly disposed of at a shoreside pumpout facility. Can be equipped with

a discharge option, called a Y-valve, that allows the boater to direct the

discharge from the head either into the holding tank or directly overboard.

Overboard discharge is illegal in U.S. navigable waters.

Table 3-1. Marine sanitation device descriptions
SECTION 3: Nonpoint Source Pollution Control

3-5

whether the implementation is voluntary or

mandatory (e.g., required under a storm water

permit).

Important Characteristics of Marina

Environments from a Pollution Perspective

Marinas are located on nearly every type of

surface water—lakes, rivers, inland waterways,

reservoirs, embayments, bays, coastal channels,

and others. Each of these waterbody types has

different characteristics that affect how pollutants

behave in them; that is, whether they are diluted

quickly or not, accumulate in sediments or remain

in the water column, or concentrate in specific

areas or disperse. Although marina operators

cannot affect the qualities of or processes that

occur in waterbodies, knowledge of the qualities

and processes particular to the type of waterbody

where a marina is located is useful when devising

a pollution control strategy and in general for

helping to understand the larger watershed

context within which every marina is located.

General Factors Common to All Waterbodies

Sediment has the potential to be a concern at any

marina because of the turbid waters it can create,

the dredging that might become necessary if too

much sediment accumulates in the marina basin,

and the pollutants it can carry with it. Sediment

can enter a marina from upland flow (storm water

runoff) and from surrounding waters. The amount

of sediment contained in either of these sources is

very site-specific and needs to be assessed

individually at each marina.

Along with the sediment are nutrients and toxic

substances attached to sediment particles. The

types and quantities of these pollutants are other

factors that are best assessed on a site-specific

basis. Many chemicals (including nutrients and

chemical pollutants) have different forms with

different tendencies to attach to particles, biodegrade, and volatilize. Each chemical form might

have a different toxicity to aquatic life. The

chemical form can change when the compound

moves from one environment to another––for

instance, from ground water to surface water or

from fresh water to salt water. Heavy metals

naturally react to particles and sorb onto suspended particulates. This process is particularly

accentuated in estuaries, where the mixing of

fresh and salt water creates turbulent and turbid

conditions. Most metals transported down rivers

to estuaries are removed to bottom sediments in

the estuary.

Pollutant resuspension is another potential concern in marinas, and it is affected by currents,

boat traffic, and dredging. Toxic metals and

hydrocarbons are often mentioned in the context

of pollutant resuspension, but bacteria and viruses,

nutrients, organic matter, and any other pollutants

concentrated in sediments are also resuspended

by water turbulence and can cause water quality

problems.

The type of waterbody on which a marina is

located plays a role in processes in the marina

basin, like sedimentation; pollutant delivery,

settling, and resuspension; and circulation. The

subsections that follow discuss the general types

of environments where marinas are located and

factors of concern in each of them.

Lakes and Reservoirs

Lakes and reservoirs are strongly affected by the

characteristics of the watersheds in which they

are located, more so than coastal waters because

lakes and reservoirs are not flushed and mixed

with a larger body of water. Water that enters

lakes and reservoirs carries with it nutrients,

sediment, oxygen, decomposing organic matter,

fertilizers and pesticides used on farms and lawns,

and weathered minerals. In addition, pollutants

from on-site waste disposal systems (septic tanks)

that leak into ground water, industrial and municipal point sources that discharge into rivers and

streams that then feed into the lake or reservoir,

street runoff, and pollutants from the atmosphere

all enter lakes and reservoirs and affect their

ecology.

The water quality and biological effects of

pollutants discharged into the waters of lakes and

reservoirs depend on a combination of lake and

reservoir characteristics. Depth is one of the

characteristics that determines the effect of

marinas and recreational boating in a lake or

reservoir. Lakes and deeper reservoirs are usually

thermally divided during the summer into distinct

upper (epilimnion) and lower (hypolimnion)
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National Management Measures Guidance

Watersheds are areas of land that drain to

a single stream, lake, or other water

resource. Watersheds are defined solely

by drainage areas and not by land ownership or political boundaries.

portions. Because the density of water depends

on its temperature, the temperature difference

between the upper and lower portions creates a

difference in density as well. Wind circulation

alone is not enough to overcome the density

difference between the upper and lower portions,

so there is little exchange of dissolved oxygen

between the upper portion and the lower portion

while a lake or reservoir is divided in this manner.

The epilimnion usually has a depth of from about

10 feet in shallow lakes to 40 feet in deep lakes.

A narrow region where water temperature

changes rapidly with depth (usually about 1.5 oF

per 3 feet of depth), the thermocline, rests

between the epilimnion and the hypolimnion. The

hypolimnion is more or less uniform in temperature and extends from the base of the thermocline

to the bottom of the lake or reservoir.

Stratified lakes and reservoirs have two periods of

overturn or mixing each year, one in the autumn

and another in the spring. The change of season

from a warm summer to a cold winter destratifies

lakes and reservoirs and induces mixing; the

reverse process of warming with the change from

winter to summer induces another mixing period.

Because there is limited exchange of dissolved

oxygen between the epilimnion and the hypolimnion while a lake or reservoir is stratified, the

oxygen depleted in the hypolimnion during the

summer is not replenished until the autumn

overturn. During the overturn, when a lake or

reservoir is unstratified, dissolved oxygen is

usually uniformly distributed from the surface to

the bottom.

Stratification and mixing of lakes and reservoirs

influence the effect of pollutants on them. When a

lake or reservoir is stratified, the upper

(epilimnetic) volume of the lake or reservoir

determines the volume of water available for

dilution of fuel, oil, and other wastes that are not

mixed into or do not sink into the hypolimnion

while the waterbody is stratified. The total volume of

the lake or reservoir determines the volume of water

available to dilute pollutants over time.

Another important characteristic of lakes and

reservoirs is the hydraulic residence time (HRT).

The HRT of a lake or reservoir is the time it

would theoretically take for all of the water in the

lake or reservoir to be replaced by new water

entering it naturally. For example, if a lake has a

volume of 5 million gallons and natural flow into

the lake from streams averages 10,000 gallons per

day, the HRT of the lake would be 500 days

(5,000,000/10,000). In a lake with an HRT of 10

years, therefore, even if pollution input were

completely stopped, existing lake water would

predominate for many years while new water

slowly replaced the polluted water. There would

be a long lag time (perhaps 2 to 3 years) before

improvements in lake water quality would be seen.

Rivers

Water quality at any point along a river is strongly

influenced by upstream water and land uses. If

the conditions that affect upstream water quality

change, downstream water quality is affected.

Examples of upstream changes in conditions

include clearing land near the river for construction or forest harvesting, which might increase

sediment loading, or changing land use change

from forest to agriculture, which could increase

sediment, nutrient, and chemical pollution. Water

quality changes at downstream locations can

occur in pulses if inputs of pollutants from upstream dredging or pesticide and fertilizer

applications, for instance, are short-lived. The

duration of changes in water quality depends on

the type of upstream change. A change in land

use from forest to agriculture over a large area,

for instance, could cause long-term changes in

water quality, whereas an increase in suspended

sediment from dredging might last no longer than

the duration of the dredging work.

Estuaries

Estuaries are similar to coastal embayments with

the special characteristic of receiving fresh water

from upland areas via rivers and streams. This

characteristic creates special circumstances and

properties. Where fresh water meets salt water,

there is a change in salinity and alkalinity, a
SECTION 3: Nonpoint Source Pollution Control

3-7

change in water density (because salt water is

more dense than fresh water), a loss of water

velocity, and turbulence due to the meeting of

fast-moving river water and quiescent estuarine

water. These factors affect the behavior of

sediment and the pollutants attached to it.

Sedimentation is greater in the upper portions of

estuaries where rivers enter because of the

water’s loss of velocity. Sedimentation also

occurs where the fresh water and salt water meet

because the change in salinity causes suspended

particles to join together into larger particles and

settle. The changes in salinity and pH affect many

pollutants, such as nutrients and toxic metals, in

the incoming fresh water as well. The form of a

pollutant might change because of these changes

in the water, making it less or more toxic or

causing it to attach to or detach from sediment

particles. As in coastal embayments, the force of

tides influences estuarine environments as well.

Coastal Environments

Coastal environments are areas of high energy,

with tides moving in and out, coastal storms,

waves constantly washing against the shore, and

currents moving along the coast. Marinas cannot

afford to be subject to all of this energy because

of the need to offer protection for boats and

on-land structures; therefore, they are usually

located on quieter embayments along the coast or

are protected from coastal energies by artificial

means like breakwaters. However, the energetic

processes of the coast still exert a strong effect

on the water quality and aquatic environment of

marinas.

Coastal embayments have quieter waters than

open coastal areas, and sediments tend to accumulate in quiet-water areas because the lack of

water movement permits the sediment to settle.

Countering this tendency are tides and coastal

storms that mix sediments from the bottom and

transport them to open waters. So, in marinas

located in coastal embayments, pollutants can

build up if tidal action is not strong or the

embayment is well protected from storm action.

As noted above, metals transported down rivers

to estuaries sorb onto particulates and settle to

sediments. In general, more than 90 percent of

particulate matter transported by rivers settles in

estuarine and coastal marine areas and does not

escape to offshore waters.

Modification of coastal areas—for example, by

excavating coastal land to create a marina or by

adding breakwaters—can alter coastal currents

near marina entrances. The effect in any particular area depends on local conditions relating to

currents and the sizes and types of sediments

transported by them. Coastal currents carry

sediments with them, and these sediments tend to

be transported into channels that lie perpendicular

to the current. Artificial structures and channels

can also alter erosion patterns due to alterations

of wave patterns in the immediate vicinity. Thus,

marinas in altered coastal environments might

have to contend with problems of sedimentation

and erosion that were not present before the

coastal alterations.

Boating on Inland Waters

A picture of a marina on a large inland reservoir,

lake, or river would look very similar to a picture

of a coastal marina. Lakes and reservoirs range in

size from small (an acre or less) to very large.

Reservoirs operated by the Tennessee Valley

Authority range in surface area size from relatively small (10 to 12 miles long by 1⁄2 mile wide)

to large (180 miles long by 1 mile wide), and their

depths typically range from 100 to 300 feet. The

size of a lake or reservoir dictates the types of

boats that can be used on it, and the boats used on

large inland lakes and reservoirs are usually of the

same types (keeled sailboats, large motorboats,

and yachts) as those used along the coast.

Marinas on large lakes and reservoirs are also

very similar to coastal marinas. They can have as

many as 200 slips (some marinas on Lake

Winnipesaukee in New Hampshire have 150 to

200 slips); they often have fueling stations,

pumpout services, and hull maintenance areas;

boat use is concentrated on the weekends, with

holiday weekends being especially busy. Inland

marinas can also be smaller, especially those

located on smaller lakes and rivers. A directory of

marinas in Louisiana lists 51 marinas on freshwater lakes, rivers, and bayous with capacities of as

few as 10 boats in slips or moorings.
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National Management Measures Guidance

Because reservoirs are dendritic (that is, they

have a branching configuration; see Figure 3-1),

the surface area in their main channels is limited.

Marinas or docks extending into the main channel

of a reservoir would impede navigation, and

therefore they are typically located to the side of

the main channel. Some typical features of lakes

and reservoirs are summarized in Figure 3-1.

Boating Access

In 1984 Congress created the Aquatic Resources

Trust Fund, which made two sources of funding

available for the acquisition, design, and construction of recreational boating facilities. The Boating

Safety Account is administered by the U.S. Coast

Guard and primarily provides grants to states to

help finance boating safety programs, one element

of which is access. The Sport Fish Restoration

Account is administered by the U.S. Fish and

Wildlife Service. Ten percent of revenues to the

account from recreational user taxes and a

marine fuel tax must be expended by states for

boating access. States may also use funds from

the account to operate and maintain recreational

boating facilities.

The States Organization for Boating Access

(SOBA) was created in 1987 to promote the

acquisition, development, and administration of

recreational boating facilities. The organization

maintains close ties with the Coast Guard and

Fish and Wildlife Service both to ensure that the

boating access aspects of the grant programs

administered by these agencies receive the funds

and attention that Congress intended and to provide

input from states on program requirements.

Construction of boat ramps is an aspect of boating

access that can affect shorelines and water

quality in inland waters. Where appropriate,

measures that can help protect the environment

and ensure attractive and safe boating access

points are highlighted throughout this document

and are based on the concepts developed by

SOBA. A thorough treatment of the topic can be

found in SOBA’s book Design Handbook for

Recreational Boating and Fishing Facilities

(1996), available from SOBA at 919-781-0239.

Figure 3-1. Typical features of and differences between lakes and reservoirs.