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DIRECTOR’S ORDER #47:
SOUNDSCAPE PRESERVATION AND NOISE MANAGEMENT Approved:/s/ Robert Stanton Effective
Date:
December 1, 2000 Sunset
Date:
December 1, 2004 Table
of Contents A. Purpose
and Background
D.Definitions A.
PURPOSE AND BACKGROUND The purpose
of this Director’s Order is to articulate National Park Service operational
policies that will require, to the fullest extent practicable, the
protection, maintenance, or restoration of the natural soundscape resource in
a condition unimpaired by inappropriate or excessive noise sources. Natural Sounds
and the NPS Mission. An important part of the NPS mission is to preserve
and/or restore the natural resources of the parks, including the natural
soundscapes associated with units of the national park system. Natural sounds
are intrinsic elements of the environment that are often associated with
parks and park purposes. They are inherent components of "the scenery
and the natural and historic objects and the wild life" protected by the
NPS Organic Act. They are vital to the natural functioning of many parks and
may provide valuable indicators of the health of various ecosystems.
Intrusive sounds are of concern to the NPS because they sometimes impede the
Service's ability to accomplish its mission. Intrusive
sounds are also a matter of concern to park visitors. As was reported to the
U.S. Congress in the "Report on the Effects of Aircraft Overflights on
the National Park System," a system-wide survey of park visitors
revealed that nearly as many visitors come to national parks to enjoy the natural
soundscape (91 percent) as come to view the scenery
(93 percent). Noise can also distract visitors from the resources and
purposes of cultural areas--the tranquility of historic settings and the
solemnity of memorials, battlefields, prehistoric ruins, and sacred sites. Increasingly,
even those parks that appear as they did in historical context do not sound
like they once did. Natural sounds are being masked or obscured by a wide
variety of human activities. In some parks, natural sounds are disappearing
at such a rate that some may be gone before their existence can even be
documented. Thus, soundscape preservation and noise management is one more
dimension of the complex problem of achieving the NPS mission of preserving
park resources unimpaired for the enjoyment of present and future
generations. Appropriate
and Inappropriate Noise. Park purposes are defined in enabling legislation or
proclamations, and through a comprehensive public planning process. Park
purposes may be highly varied, in the same way that activities appropriate to
each park's purpose may be highly varied. Park activities may include
transportation systems, visitor centers, maintenance activities, recreational
activities, weapons-firing demonstrations, cultural events, and many others.
These activities are often found to be appropriate even though they generate
elevated sound levels for areas within the parks. However, when activities
(whether inside or outside a park) generate excessive levels of noise, they
can jeopardize the natural soundscape resource and/or the purposes for which
the park was created. Addressing
the Problem.
This Director’s Order addresses the problem of excessive/ inappropriate
levels of noise. It directs park managers to (1) measure baseline acoustic
conditions, (2) determine which existing or proposed human-made sounds are
consistent with park purposes, (3) set acoustic management goals and
objectives based on those purposes, and (4) determine which noise sources are
impacting the park and need to be addressed by management. Furthermore, it
requires park managers to (1) evaluate and address self-generated noise, and
(2) constructively engage with those responsible for other noise sources that
impact parks to explore what can be done to better protect parks. In this regard,
the Service will give appropriate recognition and weight to the vital
missions of other government agencies, such as the Federal Aviation
Administration (FAA) and the military services, and respect the rights of
park neighbors. B.
AUTHORITY Authority to
issue this Director’s Order is contained in the National Park Service Organic
Act, as amended (16 USC 1 through 4), and delegations of authority contained
in Part 245 of the Department of the Interior Manual. C.
INSTRUCTIONS AND REQUIREMENTS To
accomplish the purpose of this Director’s Order, the NPS will apply the
following requirements to its soundscape preservation and noise management
activities. 1.
Applicable Policies Soundscape
preservation and noise management activities will be subject to the policies
contained in NPS Management Policies. The portions of Management Policies
that are most pertinent to this topic are: Chapter 1, Introduction; Chapter
4, Natural Resource Management; Chapter 5, Cultural Resource Management;
Chapter 6, Wilderness Preservation and Management; and Chapter 8, Use of the
Parks. Policies in the form of regulations covering general audio
requirements are published in title 36, section 2.12, of the Code of Federal
Regulations. Policy on the regulation of commercial air tourism is
established by Public Law 106-181, and implementing FAA regulations. 2.
Reference Manual The
Associate Director for Park Operations and Education will develop and
maintain a reference manual (RM-47) to provide comprehensive guidance on soundscape
preservation and noise management. The reference manual will include
applicable policies and procedures; technical guidance on planning,
inventory, monitoring, education, noise prevention and mitigation; and other
information that will help field managers and staff to meet their
responsibilities. 3.
Soundscape Preservation and Noise Management Planning Superintendents
will address the preservation of natural soundscapes and the elimination,
mitigation, or minimization of inappropriate noise sources through NPS
planning processes (see Director’s
Order #2: Park Planning) and operations policies. Soundscape preservation
and noise management can be addressed in appropriate sections of General
Management Plans or through a variety of park implementation plans. If needed
to deal with the complexity or urgency of a noise issue, a separate
implementation plan (e.g., a Soundscape Preservation and Noise Management
Plan as described in Reference Manual 47) will be developed. These park
planning efforts will (1) describe the baseline natural ambient sound
environment in qualitative and quantitative terms; (2) identify sound sources
and sound levels consistent with park legislation and purposes; (3) identify
the level, nature and origin of internal and external noise sources; (4)
articulate desired future soundscape conditions; and (5) recommend the
approaches or actions that will be taken to achieve those conditions or
otherwise mitigate noise impacts. 4.
Interim Noise Management Measures Where noise
management actions – particularly those related to park-generated noise or
noise from sources covered by existing regulations – do not require a
planning process with public participation, superintendents will act to
lessen the impact of noise in parks by identifying the inappropriate and
intrusive noise sources and by implementing any immediately feasible
mitigation or preventative measures. Noise Prevention and Mitigation
Considerations in Reference Manual 47 will provide guidance in this process. 5.
Inventorying and Monitoring the Soundscape As needed
for baseline resource inventory, soundscape preservation and noise management
planning, development of interim management measures, commercial air tour
management planning purposes, or for other plans (general management plans,
commercial services plans, use management plans, etc.), superintendents will
inventory and monitor park soundscapes as described in Reference Manual 47.
The information provided from inventory and monitoring is essential to
understanding the relationship between the baseline natural soundscape and
human-made components of the soundscape--existing and proposed. This
information (1) makes it possible to better understand the resource that needs
to be protected and the appropriate and inappropriate sources of noise; (2)
enables a park to define acoustic goals for different parts of the park, and
to determine the nature and level of impacts; and (3) suggests where
management intervention can most effectively contribute to protecting park
resources and improving the visitor experience consistent with park purposes.
Monitoring over time will allow measurement of progress toward defined
acoustic goals. 6.
Establishing Soundscape Preservation Objectives In the
planning process, acoustic objectives must be established to define the
desired future soundscape conditions of parks. These objectives must be
consistent with park purposes and plans, as well as with the goal of
returning the soundscape to as near natural conditions as possible over time
– while allowing visitors to access and enjoy the park in a manner consistent
with park management goals. The timeframe for this restoration will be a
function of local conditions and will be established in appropriate planning
documents. The
fundamental principle underlying the establishment of soundscape preservation
objectives is the obligation to protect or restore the natural soundscape to
the level consistent with park purposes, taking into consideration other
applicable laws. Where natural soundscape conditions are currently not
impacted by inappropriate noise sources, the objective must be to maintain
those conditions. Where the soundscape is found to be degraded, the objective
is to facilitate and promote progress toward the restoration of the natural
soundscape. This basic principle is modified by two circumstances: (a) The
first is where the Congress has legislated (e.g., through park legislation,
the Alaska National Interest Lands Conservation Act, the Wendell H. Ford
Aviation Investment and Reform Act for the 21st Century) specific
provision for noise-making activities, and then only to the extent that the
noise cannot be contained below certain levels consistent with that activity.
If, for example, congressional action provided for a noise-producing activity
in or next to a national park, the soundscape management goal would be to
reduce the noise to the level consistent with the best technology available –
to mitigate the noise impact, but not adversely affect the authorized
activity. (b) The
second circumstance relates to noise-generating activities that are
appropriate to the park under the NPS Organic Act and other relevant
legislation related to natural and cultural resource management or the
provision of visitor services. This includes many appropriate management and
maintenance activities, visitor and permittee activities, concession
operations, etc. In these situations, soundscape management goals are to
reduce noise to minimum levels consistent with the appropriate service or
activity, as long as that service or activity continues to be needed. It is
critical that the Service lead by example and not impose conditions on others
that the Service is not itself prepared to implement. Where appropriate new
services or activities are initiated consistent with park management plans,
soundscape management goals will be adjusted to the extent necessary to
facilitate the service or activity. Another consideration in this regard is
the management of permitted noise-generating activities, such as concerts in
urban parks, to ensure that noise is kept to levels that will not adversely
impact residents of adjacent neighborhoods. 7.
Defining Impacts on Park Soundscapes In planning
for soundscape preservation and noise management, superintendents must use
the best science available to determine the impact of existing or proposed
noise sources on the soundscape, wildlife, aquatic and marine life, cultural
resources, other resources and values, and the visitor experience, as
appropriate. With respect to determinations related to the impacts of sound
on the park soundscape, the natural soundscape is the "affected
environment." Under 16 USC 1 et seq., the Service possesses broad and
sole authority to manage the lands, resources, and visitors in the areas
under its charge. The Service has the "special expertise" and
"jurisdiction," as the terms are used in the National Environmental
Policy Act and its implementing regulations, to determine the nature, extent,
and acceptability of impacts on park resources and visitors. This includes
determining the type, magnitude, duration, and frequency of occurrence of
noise that is compatible or incompatible with protecting the resources or the
visitor experience for which the park was established and planned, as well as
determining the significance of noise levels or impacts. This may also
include determining whether certain noise sources are necessary or
appropriate. In some cases, it may be necessary for parks to conduct
additional ecological and sociological studies to better understand the
extent and nature of actual or potential impacts on park resources or
visitors. Even in
those situations where the responsibility for assessing the noise impacts of
its proposed action rests with another Federal agency, under guidance
established by the Council on Environmental Quality (CEQ) in implementing the
National Environmental Policy Act, the NPS has jurisdiction by law and
expertise to determine the effects of that noise on units of the national
park system. CEQ guidance indicates that these agencies must take NPS
standards and evaluations into account in the evaluation of impacts. 8.
Constructive Engagement Superintendents
must work constructively and cooperatively with those responsible for inappropriate
sources of noise in parks, including NPS operations, permittees, visitors, commercial tours with or without commercial use
permits, concessionaires, and park neighbors. In some cases, such as where
there are aircraft overflights or noise sources located outside park
boundaries, other agencies or entities may have jurisdiction over the
noise-producing activity. However, where such activity impacts park resources
or visitors, the Service has the obligation to protect and manage park
resources and visitors, and Service jurisdiction may overlap or interact with
the other agency's jurisdiction in complex ways. The vital missions of other
government agencies such as the FAA and the military services, and park
neighbors, must be given appropriate consideration in the process of setting
soundscape preservation and noise management goals and objectives. The
Service will work constructively with other agencies and entities to minimize
and mitigate any impacts to park resources or visitors. 9. Air
Tour Management Planning Public Law
106-181 and implementing FAA regulations provide for a cooperative FAA/NPS
public planning process to develop an Air Tour Management Plan (ATMP) when
and where a commercial air tour operator seeks to provide tours over units of
the national park system (the legislation exempts Grand Canyon National Park,
Rocky Mountain National Park, and parks in Alaska from the process). The
Service will assist the FAA in this localized process and determine the
nature and extent of impacts on natural and cultural resources and visitor
experience opportunities. The FAA, with responsibility for ensuring the safe
and efficient use of the nation’s airspace and for protecting the public
health and welfare from aircraft noise, will lead the ATMP effort and
regulate these commercial activities as provided for in the cooperative
planning effort. The FAA and the NPS must approve and sign the environmental
decision document required by NEPA, which may include a finding of no
significant impact, an environmental assessment, or an environmental impact
statement, and the record of decision for the ATMP. This requires
superintendents to work cooperatively with the FAA, air tour operators, and
other stakeholders in the development of these plans. Procedures for this
interagency process, and plan content requirements, are provided in Reference
Manual 47. 10.
Interpreting the Soundscape to Visitors Educating
the American public about the nation’s natural and cultural heritage is one
of the fundamental responsibilities of the National Park Service and is
central to its resource preservation efforts. Superintendents will use
educational and interpretive materials (e.g. The Nature of Sound education
materials) on the natural soundscape and its values to educate visitors about
their soundscapes. Internally, NPS staff will lead by example by minimizing
use of mechanical equipment, and by using the quietest and least impacting
technologies available. 11.
National Program Steering Committee The
Associate Director for Park Operations and Education may establish a program
steering committee to promote consistency and improvement in NPS soundscape
preservation and noise management efforts, and to facilitate interagency
coordination and actions. The committee will (1) assess NPS progress toward
natural soundscape restoration and preservation; (2) review programmatic
needs and provide recommendations on resource needs; (3) identify and assess
programmatic issues; and (4) provide recommendations and advice to establish
accountability, consistency, and continuity within the program. An
established committee will function until such time as the Associate Director
determines the committee is no longer needed. D.
DEFINITIONS The
following definitions apply to this Director’s Order: 1. Sound A mechanical
wave or an oscillation in pressure, stress, particle displacement, and
particle velocity transmitted though solids, liquids, and gases—some types of
which are able to cause a sensation of hearing. The vibration causes the
propagation of sound waves. Basic analytical parameters of sound include:
frequency, amplitude (related to sound pressure and intensity), envelope
(shape of amplitude in time), spectrum and duration. 2.
Soundscape Soundscape
refers to the total ambient acoustic environment associated with a given
environment (sonic environment) in an area such as a national park. It is
also refers to the total ambient sound level for the park. In a national park
setting, this soundscape is usually composed of both natural ambient sounds
and a variety of human-made sounds. 3.
Natural Ambient Sound Level The natural
ambient sound level of a park is the natural soundscape of that park. It is
comprised of the natural sound conditions in a park which exist in the
absence of any human-produced noises. These conditions are actually composed
of many natural sounds, near and far, which often are heard as a composite,
not individually. In an acoustic environment subjected to high levels of
human-caused sound, natural ambient sounds may be masked by other noise
sources. The natural soundscape is an important resource of parks; there may
also be important relationships between how this environment is perceived and
understood by individuals and society. (Natural ambient sound is considered
synonymous with the term "natural quiet.") This is the basis for
determining the "affected environment" in NEPA documents and other
environmental assessments related to human actions producing inappropriate or
intrusive impacts on the park soundscape. 4.
Background Sound Level This is the
sound level that can be measured in those situations where it is not possible
to measure the natural ambient sound level with certainty because of high
levels of human-caused sound, or where it is prohibitively expensive to measure
natural ambient sound levels. In such situations, this level will be
estimated using a statistic called L90, the sound level that is
exceeded 90 percent of the time. This metric is often used in acoustics
literature to characterize "background" or "ambient," and
is incorporated, for example, in state laws in Massachusetts, Connecticut and
Illinois. 5.
Man-made Sound Levels The ambient
sounds attributable to human activities in national parks are defined as
human-made sound. The sound levels associated with these sounds are actually
composed of many human-made sounds, near and far, which may be heard
individually or as a composite. In a national park setting, these sounds may
be associated with activities that are essential to the park's purpose, they
may be a by-product of park management activities, or they may come from
outside the park. It is these sounds and sound levels that need to be
measured and evaluated in park planning processes to determine whether they
are consistent with or destructive to soundscape management objectives. 6. Noise Noise is
generally defined as an unwanted or undesired sound, often unpleasant in
quality, intensity or repetition. This makes noise a subjective term and
pushes society to address which sounds or aspects of sound constitute
unwanted interruptions in specific situations. Noise is often a byproduct of
desirable activities or machines. In a national park setting, noise is a
subset of human-made noises. National park staff are responsible for
analyzing the sound energy associated with human activities and defining
which sounds are appropriate or necessary for park purposes within the
various park management zones, and which sounds are inappropriate or impact
park purposes within various park management zones. ----------End of Director's
Order---------- |
