IDENTIFYING, INVESTIGATING &
CHARACTERIZING UNKNOWNS
WHAT ARE UNKNOWNS &
HOW ARE THEY
IDENTIFIED?
• Unknowns are typically linear conductors or targets which can not
be readily correlated to available record information, utility related
structures or positively identified utility configurations.
• Unknowns are typically identified through the employment of surface
geophysical equipment during a Quality Level “B” (QL-B) subsurface
utility engineering (SUE) investigation.
• Unknowns may also be discovered during the excavation of Quality
Level “A” (QL-A) test holes or while investigating utility related
structures such as manholes, vaults, inlets, cabinets and pedestals.
• In some cases, unknowns may first show up as unidentified facilities
on plans, permits or record drawings.
UNKNOWN CONDUCTORS vs.
UNKNOWN UTILITIES
NON-UTILITY CONDUCTORS
UNKNOWN UTILITIES
Old Fencing
Typically found near existing or old
ROW lines.
Rebar
Typically found in curbs, sidewalks &
concrete paving.
Railroad & Trolley Tracks
Typically found in older urban,
metropolitan and industrial areas.
Construction/Demolition Debris
Occurs randomly on a small
percentage of projects.
Undocumented “Active” Utilities
Found everywhere, they are most often
communications, traffic control and privately
owned facilities.
Abandoned Communications
Most often found in suburban and rural areas,
their number are growing rapidly.
Abandoned Natural Gas & Water
Most often found in older urban,
metropolitan and industrial areas.
Aban & Gas Gathering Systems
Commonly found in regions with a history
of oil & gas production.
Steam & Pneumatic Systems
Casings and Culverts
WHAT ARE THE PRIMARY GOALS
OF INVESTIGATING UNKNOWNS?
ATTEMPT TO DETERMINE THE FOLLOWING:
•
What is it?
Obtaining this information is critical because it is the only way to eliminate
non-utility related targets. It also allows for the narrowing of search
parameters aimed at determining ownership.
•
Who owns it?
The determination of ownership is critical because it establishes a direct
contact for obtaining additional facility specific information. Direct contact
with the owner also facilitates the timely negotiation, design and planning
of relocations.
•
What is its operational status?
This information is critical regardless of the establishment of ownership.
The time and costs associated with removing “abandoned” facilities are
far less than those associated with the design and relocation of “inactive”
or “abandoned” facilities.
HOW CAN WE DETERMINE
WHAT IT IS?
• Employ surface geophysical equipment to tie the target in to a utility
related structure or positively identified utility configurations.
This may require investigation beyond the strict limits of the project.
• Research additional sources of record and anecdotal information.
These sources may include “archival” utility records, permits,
deeds, tax records, public libraries, county courthouses, regulatory
agencies, property owners, the internet, etc.
• Employ non-destructive excavating techniques to expose the target.
Exposure will allow for the elimination of non-utility unknowns. It also
allows for the collection of important physical information such as
the size, material type and general condition of unknown utilities.
HOW CAN WE DETERMINE
OWNERSHIP?
• Employ surface geophysical equipment to tie the target in to a utility
related structure or positively identified utility configurations.
This may require investigation beyond the strict limits of the project.
• Research additional sources of record and anecdotal information.
These sources may include “archival” utility records, permits,
deeds, tax records, public libraries, county courthouses regulatory
agencies, property owners, internet, etc.
• Post public notices as required by state and local statutes.
• Is there an owner?
Abandoned utilities are often not included in the sales, mergers, etc.
of corporate interests. In these cases, ownership may have reverted
to the surface owner.
FROM THE TxDOT UTILITY MANUAL:
Section 9: Unknown Utility Ownership Policy
Determining the ownership and authorized agent of the
utility can be accomplished by:
􀁺 visiting with people being served by the facility;
􀁺 checking with the owners or representatives of similar facilities in
the area;
􀁺 contacting the landowners where the utility is located;
􀁺 reviewing TxDOT permits and Joint Use Agreements in the area;
􀁺 investigate other adjacent roadway utilities; or
􀁺 contacting county maintenance personnel or commissioners.
Cooperative facilities may be used by consumers who are
unaware that the facilities are consumer owned, or that the
original members of a cooperative may no longer exist. Yet,
the cooperatives are responsible for the adjustment of
utilities. This situation may be remedied by the following
methods:
􀁺 Call the consumers using the facilities to a
meeting. Have the TxDOT Utility Liaison explain the
scope of the project and potential impact on the facilities.
􀁺 If the cooperative is unable to fund their portion
of the required adjustment, inform them of financing
options. These include SIB and State's Hardship
Financing Fund and other than State sources, e.g., bond.
• When ownership cannot be determined and the
utility is not abandoned or inoperative, TxDOT will
exhibit a good faith effort by publishing its intention
to abandon the utility according to State or industry
standards using a citation by publication. This
should be accomplished in the same manner as that
for a right of way parcel; refer to TxDOT’s right of
way Manual, Volume 4, Eminent Domain Guide,
Sections 3 and 8. Another method of handling this
situation could be leaving the utility in place through
highway design mitigation.
GENERALLY RECOGNIZED
OPERATIONAL STATUS
CHARACTERIZATIONS
ACTIVE – Any or all of the following may
apply:
• The utility owner has characterized the operational
status of this facility as ACTIVE .
• There is physical, electronic, record or anecdotal
evidence found to suggest this facility is in regular use.
GENERALLY RECOGNIZED
OPERATIONAL STATUS
CHARACTERIZATIONS
INACTIVE – Any or all of the following may apply:
• The utility owner has characterized the operational
status of this facility as INACTIVE .
• There is physical, electronic, record or anecdotal
evidence found to suggest this facility is not in regular
use.
• There is physical, electronic, record or anecdotal
evidence found to suggest this facility is serviceable or,
could be economically repaired and returned to ACTIVE
status.
GENERALLY RECOGNIZED
OPERATIONAL STATUS
CHARACTERIZATIONS
ABANDONED – Any or all of the following may
apply:
• The utility owner has characterized the operational
status of this facility as ABANDONED .
• There is physical, electronic, record or anecdotal
evidence found to suggest this facility is not in regular
use.
• There is physical, electronic, record or anecdotal
evidence found to suggest this facility is unserviceable
and, could not be economically repaired and returned to
ACTIVE or INACTIVE status.
GENERALLY RECOGNIZED
OPERATIONAL STATUS
CHARACTERIZATIONS
UNKNOWN – Any or all of the following may
apply:
• The utility owner was unable or unwilling to characterize
the operational status of this facility.
• There was insufficient physical, electronic, record or
anecdotal evidence found to warrant a more specific
status.
HOW CAN WE DETERMINE
OPERATIONAL STATUS?
• Employ surface geophysical to search for “EOIs”.
EOI’s can indicate the cut ends of pipes or cables.
• Employ non-destructive excavating techniques to expose target
utilities.
> Physical exposure at an EOI can provide verification that a line
has been cut.
>Physical exposure at points of poor electronic information may
yield additional telling information such as holes or other conditions
which are indicative of operational status.
>Physical exposure of pipes facilitates external testing for cathodic
protection, pipe wall thickness, asbestos content and flowing liquid
or gas.
• As a last resort and provided a number of prerequisite criteria have
been met, pipes can be “cold tapped”. This facilitates direct
sampling inside of the pipe.
DOCUMENTING & REPORTING
INFORMATION
• Provide QL-B information in the appropriate
CADD platform using the client’s standards for
line styles, symbology, etc.
• Add a unique non-embedded text label i.e., A-Z,
2A-2Z, 3A-3Z to each line.
• Provide a Utility Characterization Report which
includes detailed information such as size,
material type, depth, general condition,
ownership, operational status, etc. for each line.
TYPICAL QL-B WORK PRODUCT
TYPICAL QL-B/UC WORK PRODUCT
C/I ASCE 38-02
Standard Guidelines for the Collection
and Depiction of Existing Subsurface
Utility Data
• National engineering standard published in Dec.
2002.
• Utility ownership or type should be noted when
known.
• 38-02 is silent on how much investigation should
go into determining utility ownership or type.
SCOPES OF WORK
• Most scopes of work, whether generated by the SUE
consultant or the client, fail to specifically address the
issue of unknowns.
• Therefore, individual SUE consultants will address these
issues in different ways, based upon their perception of
the owner’s expectations, pricing mechanisms, project
due dates, and other factors.
• However, lacking a scope of work to the contrary, a
majority of SUE consultants will take a relatively
minimalist approach and simply label “unidentified
conductors” as an “UNKNOWNS” and leave it at that.
Range of Practices –
Consultant 1
• Research records of the major “known” utilities.
• Employ surface geophysical equipment to
confirm only these “utilities of record”.
• If they happen across an “unidentified
conductor” it is traced to the project limits,
mapped and labeled whatever the technician
thinks it might be or simply left as an
UNKNOWN.
Range of Practices –
Consultant 2
• Research records of the major “known” utilities.
• Employ surface geophysical equipment to confirm only
these “utilities of record”.
• If they happen across an “unidentified conductor” and it
is traced to the project limits, it is mapped and labeled
whatever the technician thinks it might be or simply left
as an UNKNOWN.
• If it is traced to a utility related structure (e.g. a
telephone pedestal), it is labeled based upon it
association with that structure (e.g. telephone).
Range of Practices –
Consultant 3
• Research records of the major “known” utilities.
• Employ surface geophysical equipment to confirm the
“utilities of record” and, actively sweep the projects
to search for others.
• If “unidentified conductors” are found, they are traced to
the project limits and mapped. If no structures are found
within the project limits, they labeled as an UNKNOWNS.
• If an unknown conductor is traced to a utility related
structure (e.g. a telephone pedestal), it is labeled based
upon it association with that structure (e.g. telephone).
Range of Practices –
Consultant 4
• Research records of the major “known” utilities.
• Employ surface geophysical equipment to confirm the “utilities of
record” and, actively sweep the projects to search for others.
• If “unidentified conductors” are found, they are traced to the project
limits and mapped. If no structures are found within the project
limits, they labeled as an UNKNOWNS.
• If an unknown conductor is traced to a utility related structure (e.g. a
telephone pedestal), it is labeled based upon it association with that
structure (e.g. telephone).
• Perform additional records research and meet or
correspond with owners of “known” utilities in an attempt
to obtain additional anecdotal information leading the
identification of unknowns and their ownership.
Range of Practices –
Consultant 5
•
Research records of the major “known” utilities.
•
Employ surface geophysical equipment to confirm the “utilities of record” and, actively
sweep the projects to search for others.
•
If “unidentified conductors” are found, they are traced
for some distance
beyond the project limits and mapped within the limits. If
no structures are found within the project limits, they labeled as an UNKNOWNS.
•
If an unknown conductor is traced to a utility related structure (e.g. a telephone
pedestal), it is labeled based upon it association with that structure (e.g. telephone).
•
Perform additional records research and meet or correspond with owners of “known”
utilities in an attempt to obtain additional anecdotal information leading the
identification of unknowns and their ownership.
• If unknown is thought to be relatively shallow, a hand
excavation is performed in an attempt to at least identify
its size and material type.
SUMMARY
• Unknown conductors can end
up being almost anything from
buried railroad tracks, to
scraps of abandoned phone
cables, to active petroleum or
natural gas pipelines.
• The amount of effort required
to determine what they are,
who owns them and whether
or not they are “active” covers
a large spectrum
• Some courses of action are
simple, inexpensive, and can
be relatively effective
• Other actions may be quite
costly and time consuming,
with liability issues regarding
environmental releases or
property damage (e.g. to a line
being tapped).
• Good communications and a
clear scope of work are critical
to controlling costs, mitigating
risks, and ensuring adherence
to project timelines.
• Project owners may perceive a
conflict of interest between the
normal utility mapping scope
and the costly measures
necessary to identify some
unknowns; they may desire
separate contracts to eliminate
this perceived conflict of
interest.