Geology Report Guidelines.pmd

Guidelines for Preparing

Engineering Geology Reports

in Washington

Prepared by:

Washington State Geologist Licensing Board

November 2006

DEPARTMENT OF LICENSING

dol.wa.gov

Acknowledgements:

The Washington State Geologist Licensing Board would like to

thank the following individuals for their contributions towards

creating this document:

Engineering Geology Report Guidelines Committee:

Dave Parks, LG, LEG, LHG

Kenneth Neal, LG, LEG

Jon Koloski, LG, LEG

Bill Laprade, LG, LEG

Mark Molinari, LG, LEG, LHG

Department of Licensing Staff:

Emma Butler

Brett Lorentson

Questions or Comments?

Any questions or comments regarding the content of this document

may be directed to:

Washington State Geologist Licensing Board

PO Box 9045

Olympia, WA 98507-9045

(360) 664-1497

Fax: (360) 664-1495

[email protected]

The Department of Licensing has a policy of providing equal access to its services. If

you need special accommodation, please call (360) 902-3600 or TTY (360) 664-8885.

Table of Contents

I. Introduction .................................................................................1

II. Report Content ............................................................................2

A. General Information ...................................................................2

B. Site Characterization..................................................................3

1. Report Text ..................................................................................3

2. Illustrations ................................................................................. 4

a. Vicinity Map ................................................................................4

b. Engineering Geologic Maps and Cross-Sections ....................... 4

c. Logs of Subsurface Explorations ................................................ 5

d. Laboratory and Field Test Results............................................. 6

C. Assessment and Analysis ...........................................................6

D. Conclusions and Recommendations........................................... 6

E. Limitations ..................................................................................7

F. Signature and Stamp ..................................................................7

G. Report References .......................................................................7

III. References ................................................................................... 8

Guidelines for Preparing Engineering Geology

Reports in Washington

I. Introduction

The Washington State Department of Licensing’s (DOL) Geologist

Licensing Board provides these guidelines for the following pur-

poses:

1. to serve as a resource for consumers who engage the services of

engineering geologists; and

2. to act as a reference for engineering geologists as they practice

their profession.

These guidelines are intended to improve the quality and consis-

tency of engineering geology reports in Washington.

The elements of the practice of engineering geology are outlined in

Washington Administrative Code (WAC) 308.15.053. The elements

define a process whereby geologic information and data are gath-

ered, interpreted, synthesized, evaluated, analyzed, and then used

for a specific application, at a scale and level of intensity appropri-

ate for that application.

The following information is intended to provide guidance for the

preparation and review of engineering geology and geotechnical

reports prepared by engineering geologists in Washington. The

actual scope of services for each engineering geology study will vary

depending on the level of detail and accuracy needed for the in-

tended application. Each report should include sufficient data and

interpretation regarding geologic materials, structure, processes,

and history to support conclusions and recommendations regarding

the suitability of the site or area for the proposed activity, modifica-

tion, or use.

The guidelines do not include systematic descriptions or all avail-

able techniques or topics, nor is it suggested that all techniques or

topics be applied to every project. The guidelines are intended to be

flexible and tailored to the specific project, based on the project

complexity and scope of work. All elements of these guidelines

should be considered during the preparation and review of reports

prepared by engineering geologists.

This document contains elements from guidance publications for

preparing engineering geology reports by the Guidelines Commit-

tee of the Utah Section of the Association of Engineering Geologists,

the California Board for Geologists and Geophysicists, and the

Oregon State Board of Geologist Examiners. These and other

references are presented in Section III.

The Geologist Licensing Board has prepared these guidelines in the

spirit of service to the public and to assist public officials and

professional engineering geologists to better understand the re-

quirements of our state laws and codes. They are not intended to

affect or limit the trade or business of individuals or firms that

provide support services to the profession. If any portion of these

guidelines is determined to conflict with or contradict Washington

State law or rules, or those local ordinances governing these prac-

tices, Washington State law or rules or local ordinances will take

precedence.

II. Report Content

A. General Information

Each report should include adequate background information to

inform the reader of the reason for doing the project, who commis-

sioned the work, the location of the site, the general site setting, the

proposed land use, and the purpose and scope of the geologic

investigation. The following items should be addressed:

1. Name of the party or entity that commissioned the report.

2. Location and size of area investigated, the proposed use of the

site, and the reason the site is being evaluated (include specific

regulatory references, as appropriate).

3. Purpose and scope of the report and geologic investigation,

including specific tasks that were performed. A clear and com-

plete description of the scope of the report is an essential compo-

nent that enables readers and reviewers to understand the

purpose of the geologic investigation as well as the methods

employed.

4. Methodology used in the project, including dates specific tasks

were completed, name(s) of geologist(s) and others who com-

pleted each task, and specific details about how data were

actually gathered.

5. A description of prior work on the site or in the immediate area,

including the nature and source of available subsurface informa-

tion and geologic reports or maps. Suitable explanations of the

available data should provide a technical reviewer with the

means of evaluating the reliability of the data, if they are refer-

enced in the report. Reference to cited works or field observations

should be made to substantiate opinions and conclusions.

B. Site Characterization

The report should document the methods used to characterize the

geology of the site and potential geologic and seismic processes that

could impact the site and its suitability for the proposed use. This

geologic evaluation should include a review and summary of perti-

nent existing geologic information and data, results of field assess-

ment and exploration, and field and laboratory testing of rock, soil,

and water to characterize the site conditions to the level of detail

appropriate to meet the project objectives. The sources of existing

information and data should be clearly documented using standard

scientific bibliographic citations. Figures and maps based on

existing sources should have the sources referenced on the graphic.

The scope of field exploration and methods and laboratory proce-

dures used should be described. Documentation and characteriza-

tion of the site geology and geomorphic processes should include a

written report with appropriate maps, figures, cross-sections, and

appendices. Geologic features and data that were directly observed

and measured should be clearly distinguished from existing infor-

mation and inferences and interpretations. Laboratory test and

geophysical survey results should be tabulated or summarized

appropriately in the report and the test and survey reports ap-

pended.

1. Report Text

The following is a topical outline of site characteristics commonly

described in the body of the report. In each case, references should

be cited where applicable.

a. Topography, vegetation, and current land use, including the high

and low elevations on the site, the total relief, slope inclination,

form, and aspect, vegetation type and size, ground cover, and

changes (both in vegetation and topography) due to past devel-

opment or use. Where there is more than one slope, or there are

a variety of different landforms on a project, the site should be

subdivided into areas having similar characteristics, and each

area should be described.

b. Regional and site geology, including a general description of

relevant geologic history in the area. Descriptions should be

written in a manner understandable to the client and the

reviewer, and should include a review of previous geologic work

conducted in the region and at the project location.

c. Site geology, soil and rock unit descriptions and classifications,

including where the unit was encountered (including in explora-

tions), and other pertinent information. Figures (geologic maps,

cross-sections and logs of explorations) should be referenced

where applicable. References should be cited for the classifica-

tion systems applied to the project.

d. Geologic processes, including surficial processes (slope move-

ment, erosion and deposition, channel avulsion and migration,

flooding, expansive and collapsible soils, and subsidence, etc.),

coastal processes, seismic processes (including strong ground

shaking, surface fault rupture, liquefaction, lateral spreading,

and local tectonic deformation, tsunamis, seiches, etc.), and

volcanic processes (ash-fall, pyroclastic flows, lahars, etc.),

potentially affecting the site should be described. The process

descriptions should be applied directly to specific locations in

the project area, and should be related to the hazards that could

be imposed as a result of the proposed development or use.

2. Illustrations

One or more of the following types of illustrations are typically

included in a report:

• maps;

• annotated photographs;

• cross-sections;

• logs of explorations or geophysical testing; and

• actual results of laboratory test data.

The following paragraphs describe what are typically contained in

the respective types of illustrations:

a. Vicinity Map

A vicinity map should include the specific project site in relation

to known or familiar locations.

b. Engineering Geologic Maps and Cross-Sections

Engineering geologic maps of the area should be prepared at a

scale that shows sufficient detail to adequately define the

geologic conditions present, given the context of the proposed

application. For most purposes, available published geologic

maps are too general to provide a basis for understanding site-

specific conditions, so a more site-specific geologic map may be

needed. Depending on the nature of the project, the map may

extend into adjacent areas to adequately define significant

geologic conditions. Maps used for engineering geologic applica-

tions typically include site- or project-specific soil and rock units,

landforms, drainage characteristics, and slope and other condi-

tions related to development, such as existing cut and fill slopes,

roads, proposed building footprints, etc.

Mapping should be done on a suitable planimetric or topographic

base map or aerial photograph, at an appropriate scale with

satisfactory horizontal and vertical control. Each map or photo

should include the date and source of the base. Limitations of

maps and remote sensing data (source and accuracy) should be

clearly described.

Where detailed site-specific characteristics are important to the

specific application, such as slope stability or foundation analy-

sis, detailed cross-sections portraying actual ground measure-

ments, slope breaks, contact and ground water relationships,

and the locations of borings and other explorations should be

included. Cross-sections should display both horizontal and

vertical control, and should be drawn at a scale appropriate for

site conditions and the specific application and should include

the date of preparation and the name(s) of the person(s) who

prepared the cross-section.

The engineering geologist should report the nature of bedrock

and surficial materials, structural features and relationships,

and the three-dimensional distribution of earth materials

exposed and inferred within the area. A clear distinction should

be made between observed and inferred features and relation-

ships.

c. Logs of Subsurface Explorations

The scope and methods of subsurface explorations and geophysi-

cal surveys should be clearly summarized and include the

following:

• type of exploratory and geophysical survey equipment

and techniques used;

• operator and contractor’s name(s);

• detailed information about sampling and testing tech-

niques; and

• classification systems used.

The log of each exploration should describe the geologic materi-

als encountered including the location, depth, top and bottom

elevation, and a detailed description of drilling or excavation

characteristics, individual samples and tests, water levels,

changes in materials, and the details of installations of monitor-

ing equipment for water levels, slope movement, or other ex-

pected changes.

Locations of explorations and surveys should be clearly and

accurately shown on the site base map and cross-sections. When

the exploration is not located immediately on the location of a

cross-section, the exploration location should be noted, and the

data should be projected into the plane of the section where

appropriate.

d. Laboratory and Field Test Results

Include documentation of laboratory and field-testing as an

appendix. The laboratory and other subcontractors responsible

for the field and laboratory testing, data processing, and data

interpretation should be identified.

C. Assessment and Analysis

All engineering geologic information gathered for the project

evaluation should be synthesized to allow an assessment of (1) the

effect of the geologic conditions on the project and (2) the effect of

the project on geologic processes (i.e., slope instability and erosion).

This may take the form of geologic profiles, maps, sketches, and text

to explain a logical train of thought for the conclusions and recom-

mendations that will be presented in the following section. Report

conclusions should not be made that cannot be supported by the

geologic information and a logic that has not been established in

this section of the report. For instance, interpreted geologic profiles

should be commensurate with the subsurface information provided

and relate to the proposed project.

Models, such as those for slope stability and erosion, may be used to

support the analyses, but should not purport to convey legitimacy

to situations where the collected information is insufficient. As-

sumptions of the model and the method of data collection should be

stated. The analytical process being used should be described, along

with the types of information needed, how it is processed, and the

meaning and limitations of potential results. Assumptions such as

ground water levels and seismic coefficients should be described,

including the reasoning for their use. Variations should be de-

scribed, where appropriate. The strength values or other data

developed during synthesis should be listed. The results of the

analyses for each assumption or variation should be described.

Graphical or tabular results should be displayed.

D. Conclusions and Recommendations

This portion of the report documents the outcome of the study,

based on the syntheses, assessments and evaluations, and analyses

of geologic information, data, and interpretations used to character-

ize the project area or site. This section should describe the suitabil-

ity of the site for the proposed development or use, and should

clearly state the likely effects of the proposed development or use

on the geologic environment, as well as the likely effects of geologic

processes on the proposed development or use.

Engineering geologic recommendations may cover one or more of

the following topics, depending on the nature of the project:

• foundation strength characteristics of soil and rock;

• excavations and earthwork;

• slopes and slope stability;

• suitability of materials for use;

• surface and subsurface drainage;

• management of vegetation;

• temporary sediment control; and

• relevant regulatory issues.

This section should include recommendations regarding additional

work needed to supplement the report, including, but not limited to,

monitoring of geological conditions (ground water, slope movement,

etc.), review of plans and specifications, and construction monitor-

ing. Relative to the intended land use include a statement concern-

ing the degree of confidence in and limitations of the data and

conclusions.

E. Limitations

The limitations section should briefly restate the location, intended

purpose, intended audience of the report, and what tasks were

accomplished in meeting these ends. The limitations should include

a statement regarding the limits of the intended use of the report,

including scope and extent, and should restate any additional needs

beyond the stated scope of work.

F. Signature and Stamp

All final reports or other documents must be signed and sealed/

stamped by the engineering geologist who prepared and/or was in

responsible charge of the engineering geology report

(WAC 308-15-075).

G. Report References

Reference all pre-existing information used in the report using

standard bibliographic citations. Include:

1. Literature, maps, and records cited and reviewed.

2. Aerial photographs or images interpreted, listing the type, scale,

source, and index numbers etc.

3. Other sources of information, including well records, personal

communications, or other data sources.

III. References

The following references are provided for use in preparing engi-

neering geologic and geotechnical reports. In addition to the refer-

ences listed, most county and city critical areas ordinances, as well

as the Washington Forest Practices Rules (WAC 222) contain a

section on reporting requirements.

California Department of Conservation. 1999. Guidelines For

Engineering Geologic Reports For Timber Harvesting Plans. Divi-

sion of Mines and Geology, Note 45.

California Department of Conservation. 2001. Guidelines For

Preparing Geologic Reports For Regional-Scale Environmental and

Resource Management Planning, Note 52. Division of Mines and

Geology, 801 K Street, MS 14-34, Sacramento, CA 95814-3532.

California Geological Survey. 2004. Guidelines for Reviewing

Geologic Reports. CGS Note 41.

http://www.consrv.ca.gov/cgs/information/publications/cgs_notes/

note_41/index.htm

Oregon State Board of Geologist Examiners. 2005. Guidelines For

Preparing Engineering Geologic Reports in Oregon. Oregon Board

of Geologist Examiners, 707 13th Street SE, Suite 275, Salem, OR

97301.

Rogers, D.J. 2004. Standards For Geotechnical and Engineering

Geology Reports. Karl F. Hasselman Chair in Geological Engineer-

ing, Department of Geological Engineering, University of Missouri-

Rolla, 129 McNutt Hall, 1870 Miner Circle, Rolla, MO 65409-0230.

http://web.umr.edu/_rogersda/umrcourses/peer_review/

standards.htm

Slosson, J.E. 1992. Guidelines For Preparing Engineering Geology

Reports. Association of Engineering Geologists. pp. 2-12.

State of California-State and Consumer Services Agency, 1998.

Guidelines for Engineering Geologic Reports. Board for Geologists

and Geophysicists. 2535 Capitol Oaks Drive, Suite 300A, Sacra-

mento, CA 95833-2926.

Utah Geological and Mineral Survey. 1986. Guidelines For Prepar-

ing Engineering Geologic Reports in Utah. 1594 W. North Temple,

Ste. 3110, Salt Lake City, Utah 84116.

Washington State Department of Licensing. 2005. The Law Relating

to Geologists. 18.220 RCW, 308-15 WAC, The Uniform Regulation of

Business and Professions Act, 18.235. Geologist Licensing Board, PO

Box 9045, Olympia, WA 98507-9045.

dol.wa.gov