ANDSCAPE L INES 2

Levels of Investigation INTRODUCTION

The Cultural Landscape Report (CLR) has a flexible format so that it

can be used for various landscape types, address different management objectives, and guide treatment activities. While every CLR

should be similar in format and content, not every CLR needs to

contain the same level of information or have the same outline of

contents. A project agreement defines the level of investigation for a

CLR. (See Landscape Lines 1: Project Agreement.) THREE LEVELS OF INVESTIGATION

The level of investigation refers to the type and extent of information

gathered and processed during three activities conducted for a CLR.

The three activities are historical research, existing conditions investigation, and analysis and evaluation. The National Park Service (NPS)

Cultural Resources Management Guideline, defines the level of

investigation for these activities as exhaustive, thorough, and limited. DETERMINING THE LEVEL OF INVESTIGATION

Within a CLR, the level of investigation required for historical research, existing conditions investigation, and analysis and evaluation

may be different. For example, the historical research piece of a CLR

may warrant an exhaustive level of investigation because no previous

research on the landscape exists. In contrast, the existing conditions

investigation may require only a limited level of investigation because

reliable information is available from another source, such as a recent,

detailed site survey. (See Figure 1.)
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The level of investigation is influenced by several

key factors:

• legislative mandate

• management objectives

• resource significance

• resource complexity

• proposed treatment

• operations and programs

Legislative Mandate

The legislative mandate or enabling legislation

for a park describes the primary resources to

be managed. In some cases, the enabling

legislation for a park is very general with regard

to the management of specific cultural and

natural resources. In other cases, there is a

clear statement that the landscape should be

managed as a cultural resource. For example,

the enabling legislation for Weir Farm National

Figure 1. Management objectives for the Andrew Johnson National Cemetary CLR influenced the level of investigation for

both the historical research and existing conditions investigation. A limited level of historical research and a thorough level

of existing conditions investigation were required to create management zones, which indicated a historic zone, a buffer

zone, and a development zone for new interments. Andrew Johnson National Cemetery. (NPS, 1988)
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Historic Site in Connecticut states that the site

is established for the purpose of “...maintaining

the integrity of a setting that inspired artistic

expression and encourages public enjoyment....” If preservation of a cultural landscape

is identified in legislation, it may warrant an

exhaustive level of research and documentation. However, if the legislative mandate does

not give specific direction for preserving a

cultural landscape, this does not imply that an

exhaustive level of investigation is unwarranted;

rather, it means the process of defining the

objectives and level of investigation is not

directed by legislative mandate.

Management Objectives

A clear understanding of a CLR’s management

objectives is critical to defining the appropriate

level of investigation for historical research,

existing conditions investigation, and analysis

and evaluation. When information is already

available on the site history, management

objectives may require only a limited level of

historical research. When current site data

does not exist, an exhaustive level of existing

conditions investigation may be required.

Other management objectives for a CLR may

include the following:

• determination of historic significance according

to National Register criteria for eligibility

• information gathering for resource management in the absence of a proposed treatment

(such as preservation)

• information gathering for park interpretation of

the resource

It is critical that the level of investigation of historical research, existing conditions investigation, and

analysis and evaluation matches the complexity of

the management issues.

Resource Significance

Resource significance is a factor that influences

the level of investigation. There are four levels of

resource significance.

• International: cultural landscapes that qualify as

World Heritage Sites based on their universal

significance.

• National: cultural landscapes that qualify as National

Historic Landmarks are listed in the National

Register as nationally significant, or are determined

to be nationally significant by an act of Congress.

• State: cultural landscapes that qualify for the

National Register and are determined to be

significant at the state level.

• Local: cultural landscapes that qualify for the

National Register and are determined to be

significant at the local level.

Cultural landscapes that are nationally significant, such

as the Blue Ridge Parkway or the grounds of the

White House and President’s Park, may warrant an

exhaustive level of investigation because of their

value to the nation and to ensure that management

protects these values. Cultural landscapes that are

significant at the state or local level, such as a

backcountry homestead in Colorado, a settlement

community in Wisconsin, or a sheep ranch in

eastern Oregon, may not require an exhaustive level

of investigation because they are not unique and are

more representative of a type of historic property.
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Resource Complexity

The physical scale and complexity, as well as the

historic complexity of a landscape, may necessitate additional time and effort in preparing Part 1

of a CLR, titled “Site History, Existing Conditions,

and Analysis and Evaluation.” Although complexity

does not affect the type of information gathered in

preparing a CLR, it influences the effort required to

review all the research materials of landscapes with

extensive site histories or to document landscapes

that are large, have complex spatial relationships,

or have a high density of features.

Proposed Treatment

Treatment for a cultural landscape is often decided through the park planning process. Treatment may or may not be decided before a CLR is

prepared. If a proposed treatment has been

decided, a CLR documents implementation of

the treatment. If treatment has not been decided

through the planning process, but management

objectives require a CLR to recommend a

treatment, a CLR augments, or is combined with

a Site Development Plan to determine a preferred treatment and physical design. This is

outlined in the CLR project agreement along with

specific questions to be answered. (See Landscape Lines 1: Project Agreement.)

The following two examples show how the type

of proposed treatment can influence a CLR’s level

of investigation.

Example 1: If rehabilitation is the proposed

treatment for a cultural landscape and the end

product of a CLR is a new site plan or design

illustrating the location, extent, and character of

new development, then a thorough or exhaustive level of investigation is required.

Take, for example, the rehabilitation of a historic

cattle ranch landscape to accommodate a new

visitor center with parking and interpretive

facilities. Here, historical research must be sufficient to allow for a very comprehensive review

and assessment of research materials.

Existing conditions investigation and documentation must clearly illustrate the existing landscape,

portray the landscape characteristics and associated features, and identify the conditions within

which the rehabilitation can occur. The analysis

and evaluation must consolidate and compare

data from various sources (programs and professional disciplines) and from different perspectives

to evaluate the impact of treatment activities on

specific features within the landscape and identify

the best option.

Example 2: If preservation is the proposed

treatment for a cultural landscape and the end

product of a CLR is a list of acceptable plants, then

a limited level of investigation may be sufficient.

Take, for example, the replacement of plants

around a new visitor center (which is also a

historic building) with historically accurate

plants. Historical research may include a review

of primary historical records, such as drawings

or historic photographs, for the purposes of

identifying former plant materials. A review of

written documents may reveal the historic

design intent, function, or character of former
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plants, assisting in the selection of new

plantings. An exhaustive review of all historic

records related to the landscape is not appropriate. Similarly, existing conditions investigation and documentation may be limited to the

examination of extant plant materials in the

vicinity of the visitor center to identify extant

historic plant species and document their

condition and character.

The proposed treatment for a landscape defines

the level of physical intervention of subsequent

treatment activities. The level of intervention

increases from preservation, through rehabilitation, to restoration, to reconstruction. It is critical

that the level of investigation for historical research, existing conditions investigation, and

analysis and evaluation adequately matches the

type of information required for the proposed

treatment. (See Figure 2.)

Operational and Program Factors

Operational factors, such as time, budget, and

staff, and program factors, such as the relationship

of the CLR to other projects, can influence the

level of investigation. Although operational and

program factors have low priority in determining

the level of investigation, they often have a

profound impact on a project. For instance,

funding may determine the amount of time and

the staff available for a project, set travel limits on

the number of repositories a researcher can visit,

and necessitate scheduling the completion of a

CLR so that it is available for other planning and

construction projects.

LEVELS OF INVESTIGATION

Historical Research

The purpose of historical research is to develop a

historic context that defines the significance of a

landscape. Historical research is used to compose

a site history, which describes and illustrates the

appearance of a cultural landscape through each

relevant historic period.

Exhaustive Historical Research

Exhaustive historical research uses all primary

sources of known or presumed relevance,

including the following:

• historic publications, unpublished manuscripts,

and historic correspondence

• all pertinent historic graphic records, such as

drawings, plans, and photographic materials

• interviews are conducted with knowledgeable

persons, regardless of their location

Secondary sources are also reviewed, such as

studies, reports, and topical publications. All

gathered information is compiled and then documented chronologically in an illustrated narrative.

Thorough Historical Research

Thorough historical research uses selected

documentation of known and presumed relevance. This includes primary and secondary

sources that are available without extensive travel

and interviews with knowledgeable people who

are readily available. The findings are presented in

an illustrated narrative.
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Figure 2. A proposed treatment can influence a CLR’s level of investigation for both historical research and existing conditions investigation. The above plan shows a proposed restoration treatment developed as a result of an exhaustive level of

historical research and existing conditions investigation. Frederick Law Olmsted National Historic Site. (NPS, 1995)

printer to

shoot neg
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Limited Historical Research

Limited historical research uses available, selected, and published secondary sources and

primary sources, if known. Research may be

limited to sources readily accessible within or

near a park. Brief interviews are conducted (often

by telephone) to answer specific questions. The

findings are presented in an illustrated narrative.

Existing Conditions Investigation

Documentation of existing conditions requires a

site investigation involving two general activities:

site research and a site survey. The purpose of

this work is to describe and illustrate the current

appearance and condition of a landscape, including all landscape characteristics and associated

features. The documentation resulting from a site

investigation includes an existing conditions plan,

narrative text, and black and white photographs.

Exhaustive Existing Conditions Investigation

An exhaustive existing conditions investigation

involves site research, including the collection and

review of all available site data from existing

sources, including the following:

• natural and cultural resource databases (such as

the List of Classified Structures and Cultural

Landscapes Inventory)

• park maintenance records

• utility records, zoning, and other political or

legal information

• special studies (such as archeological investigations and ethnographic overviews)

• building inventories

• Vegetation Management Plans

• National Register nominations

• Historic Resource Studies

• planning documents (such as the General

Management Plan, Statement for Management,

Interpretive Prospectus, or Resource Management Plan).

• maps, plans, photographs, etc.

Information on site access, accessibility, land use,

visitor services, park operations, and interpretive

programs is also reviewed. Other site-related

documents from external sources are also examined, including soil surveys, aerial photographs, and

United States Geological Survey (USGS) maps.

The site survey involves the extensive identification

and recording of existing landscape characteristics

and associated features. Their location, appearance, and physical condition are documented in

the field using black and white photographs, color

slides, sketches, and written observations.

Additional site survey techniques may be used

to identify and describe the appearance and

condition of landscape characteristics and

associated features in the field. These techniques include:

• tree coring to determine the age of historic

trees

• aerial photography to identify and record

broad patterns of landscape characteristics

(such as natural systems and features, circulation, land use, and spatial organization) and

associated features
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• topographic and hydrographic surveys to

obtain accurate location and elevation data for

a base map

• archeological techniques, including geophysical

surveys and soil analyses to locate and analyze

buried ruins and cultural artifacts

• computer technologies to collect and process

field survey information, such as the global

positioning system datalogger as an inventory tool

and geographic information survey as a system

for mapping, analyzing, and managing site data

All findings are presented in an existing conditions

plan, narrative text, and black and white photographs.

Thorough Existing Conditions Investigation

The availability of recent and reliable site data may

make it possible to conduct a thorough, rather

than an exhaustive, existing conditions investigation. A thorough investigation differs from an

exhaustive investigation in the following ways:

• more existing site data may be used, but less new

data will be generated from the site survey

• fewer specialized technologies or techniques

will be used in the site survey

• technical and park staff expertise will be used

rather than experts from other disciplines

• less labor-intensive techniques will be used to

collect site data

A thorough level of investigation may obtain

topographic information from an aerial photograph using photogrammetry, whereas an exhaustive level of investigation may use a refined

topographic survey with a close contour interval

and include the canopy size and d.b.h. (diameter

at breast height) of mature trees.

The findings of a thorough existing conditions

investigation are presented in an existing conditions plan, narrative text, and black and white

photographs. (See Figure 3.)

Limited Existing Conditions Investigation

A limited existing conditions investigation may

use available site data and generate less new

data through the field survey than the thorough or exhaustive investigations. A limited

existing conditions investigation may focus on

just one discrete area of a landscape, use only

park and technical staff expertise, and use only

the sources of site data available in park files.

In a limited investigation, the site survey may

be performed from a less intimate vantage

point (such as a motorized vehicle) and only

discrete areas may be surveyed and documented on foot. A limited investigation may

use existing USGS topographic information or a

previous topographic survey rather than contract

for a topographic survey on the ground or through

photogrammetry. The findings are presented in an

existing conditions plan, narrative text, and black

and white photographs.

Analysis and Evaluation

Analysis and evaluation involves comparing the

findings of historical research with the findings of

the existing conditions investigation. The purpose of the comparison is twofold:
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Figure 3. The Capitol Reef CLR had a thorough level of investigation for both historical research and existing conditions

investigation. Capitol Reef National Park. (NPS, c. 1930)

• to determine the landscape characteristics and

associated features of a landscape from each

significant historic period

• to understand how the landscape characteristics and associated features contribute to and

convey the significance of the landscape (based

on National Register criteria)

An analysis and evaluation shows how a landscape has changed over time. The analysis and

evaluation may also include a statement of

significance for the landscape and identify landscape character areas and management zones.

The findings of analysis and evaluation are

documented in a narrative illustrated with

graphics, such as plans, sketches, and photographs.

Exhaustive Analysis and Evaluation

An exhaustive analysis and evaluation uses all

historic and contemporary site data from historical

research and existing conditions investigation. It
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may include park operational data, maintenance

records, and detailed condition assessments of

landscape characteristics and associated features.

The analysis and evaluation may involve the

collaboration of experts from other disciplines as

well as representatives from the public. The

gathered information can be used to deal with

various issues, such as multiple periods of significance or areas of the landscape that may receive

secondary treatments within the primary treatment plan. The findings are documented in a

narrative illustrated with graphics, such as plans,

sketches, and photographs.

Thorough Analysis and Evaluation

A thorough analysis and evaluation uses relevant

findings from historical research and existing

conditions investigation. It may involve only park

and technical staff expertise and may deal with

less complex management issues than an exhaustive analysis. The findings are documented in a

narrative illustrated with graphics, such as plans,

sketches, and photographs.

Limited Analysis and Evaluation

A limited analysis and evaluation uses findings

from historical research and existing conditions

investigation that are relevant to specific

management concerns. It involves only the

resources and staff expertise readily available and

deals with less complex management issues than

a thorough analysis. The findings are documented

in a narrative illustrated with graphics, such as

plans, sketches, and photographs.

SUMMARY

The level of investigation is influenced by a

number of factors. Ultimately, the level of

historical research, existing conditions investigation, and analysis and evaluation, should match

the level of decision making to be directed by a

CLR. If the proposed level of intervention in a

landscape is high, the level of investigation

should be thorough or exhaustive. If funding and

staffing issues limit the level of investigation for a

CLR, the resultant level of decision making

should be limited.

REFERENCE

National Park Service. 1997. Cultural Resource

Management Guideline, NPS 28, no. 5. Washington, DC: USDI, NPS.

The mission of the Department of the Interior is to protect

and provide access to our Nation’s natural and cultural

heritage and honor our trust responsibilities to tribes.

U.S. Department of the Interior

National Park Service

Cultural Resources

Park Historic Structures & Cultural Landscapes