CGE offers Geophysical Services to include:

Private Utility Markouts

Underground Storage Tank (UST) Markouts

Investigations using Ground Penetrating Radar (GPR) and Electromagnetic (EM) instruments to locate buried conductive and non-conductive features

Private Utility Markouts involve more than just GPR...

Investigations utilize a variety of instruments, methods and techniques.

Instruments:

• GPR - Ground Penetrating Radar
• EM "Metal"-Detector (split box - able to detect metallic/conductive features)
• EM Utility Line Locators

Utilities typically detected:

• Electric lines
• Water lines
• Gas lines
• Communication lines
• Sewer and Drainage lines

Procedures - A 4 step process:

1. Locate underground lines associated with above-ground features such as light posts, manholes, valves, meters, etc.

2. The EM line locators are used in active and passive methods to investigate for utilities with no apparent exposures.

3. The EM "metal"-detector is used to locate conductive subsurface utilities and features, such as USTs, buried Dry Wells, etc.

4. The GPR system is pushed across an area of concern in an attempt to locate conductive and non-conductive features of interest.

UST Investigations:

If vents, fill ports, or product/return lines are present:

• EM line locators are used in an attempt to locate UST related piping.
• If the lines are detected, apparent termination points are investigated using the EM "metal"-detector and GPR in an attempt to identify the associated UST.

If no above-ground features are present:

Areas where USTs are expected will be investigated with the EM "metal"-detector and the GPR according to the following:

If the UST is expected to be metallic:

• Areas of concern are investigated using the EM "metal"-detector.
• Metal-detector anomalies with the potential of representing a UST are further investigated with the GPR in an attempt to detect reflections typical of a UST and possibly determine a depth.
• GPR is used over select areas to aid in UST detection.

If the UST is expected to be non-metallic:

• Areas of concern are investigated with the GPR in an attempt to detect reflections typical of USTs.

Additional Services:

Concrete Investigations – High Resolution (HR) GPR

• HR GPR can typically investigate through up to ~15 inches of concrete, depending on the age and type of concrete.
• HR GPR can be used to mark locations of rebar and other features within concrete.
• Identities of features detected in GPR data cannot be confirmed without physical verification.

Deliverables - Figures and Report

Figures

If requested, the results can be mapped onto a scaled orthoimage or existing site plan, if available. Attempts are made to make locations as accurate as possible, when appropriate, but it should be noted these are not surveyed maps. When necessary, a GPS unit may be used for more accurate mapping.

Report

A written report of the investigation results and limitations can be provided. The report format can be adapted to specific project requirements.

Utility Marking Color Code

Based on the American Public Works Association

RED - Electric

YELLOW - Natural Gas, Steam, Petroleum lines and structures, Gaseous features

ORANGE - Communication

BLUE - Water

GREEN - Sewer, Drainage

PINK - Utilities and Anomalies of Undetermined Use, Temporary Survey Markings

WHITE - Proposed Excavations and Drilling Locations

Every project and every job site is unique. CGE takes time to understand expectations of every project to determine a safe, effective and efficient approach.

Geophysical Services