Subsurface Utility Exploration (SUE)
Utilizing Electromagnetic Induction and Ground Penetrating Radar (GPR), GdB incorporates this service into our suite of Land Surveying and Geospatial options, providing cost and time savings to our valued clients.
GdB provides Subsurface Utility Exploration (SUE) according to ASCE/CI 38-02, Standard Guideline for the Collection and Depiction of Existing Subsurface Utility Data. This standard was developed and published in 2002 by the American Society of Civil Engineers (ASCE). Commonly referred to as "ASCE 38", this standard is defined by four "Quality Levels" which allow the Subsurface Utility Locator to work with design and construction professionals to gather the necessary data for their projects. These standards are defined as follows:
Quality Level D - Second Hand Information
Quality Level D (QLD) is the most simple depiction of utility information. GdB researchers utilize existing records from service providers and municipalities to depict what is expected underground without any field investigation. This quality level is assigned when records or One-Call marks are the only available data and is the least certain depiction of existing conditions.
Quality Level C - Surface-Visible Survey
The most common level of quality, Quality Level C (QLC) has GdB field crews use high-accuracy survey techniques to locate existing surface utility hardware (Manholes, Valve Boxes, etc.). The measured field data is then used to confirm utility data found and drafted through record research with service providers and municipalities.
Quality Level B - Derived through Geophysics
Quality Level B (QLB) utilizes technology such as GPR and Electromagnetic Induction to determine the horizontal position of all underground utilities in the examined area. This data is tied into Survey Control for the project, creating the most accurate depiction of existing underground utilities without excavation.
Quality Level A - Derived through Excavation
The most accurate method of Subsurface Utility Exploration (SUE), Quality Level A (QLA) builds on QLB by confirming the existence, horizontal and vertical location and direction of subsurface utility assets, typically through excavation. Data collected through these methods allow the accurate plan and profile mapping of subsurface utilities to be described.
Abbey of the Genesee SUE
GdB Geospatial was contracted directly by the Abbey of the Genesee projects ream to complete a Subsurface Utility Exploration (SUE) effort on site. In order to keep their records up to date and complete, the Abbey requested a Utility survey of the entire Main Campus, and additional areas associated with the Bethlehem, Bethany, Nazareth, and Cana campuses.
To begin our efforts, GdB acquired any existing utility plans that were available based on a list of stakeholders provided by the NY811 Dig Safely New York program. Once on site, Underground utilities were mapped to ASCE Quality Level “B”, which provides the existence and approximate horizontal position of underground utilities. To complete this mapping, GdB utilized Electromagnetic Cable Locators and Ground Penetrating Radar. Once marked-out, GdB field crews mapped the location of utilities with survey grade GPS. In addition to mark-out, any sanitary and storm sewer manholes were opened to measure pipe inverts, sizes, materials, and connectivity from surface only measurements. After our initial mapping, GdB was requested to complete additional SUE mapping at the Garth, Demolished Barn, and other areas specifically noted by the Abbey.
Fire Island Substations
The main focus of this project was to determine if a new underground distribution and transmission line was feasible for this area. To assist in this effort, GdB provided Subsurface Utility Engineering (SUE) through Utility locating and mapping. Utilizing Ground Penetrating Radar (GPR) and Electromagnetic Induction equipment, GdB mapped all underground utilities along the 5-mile route according to ASCE Quality Level B standard. Locations were provided for existing utility poles, overhead wire connections, street lights, telephone & fiber optic lines, etc. All sanitary and storm water assets were opened by GdB field crews and investigated to provide details on pipe inverts, size, flow, material, etc.
Utilizing existing aerial imagery provided by PSEG LI, GdB field crews collected additional surface features in specific locations. Additional elevations and measurements were taken to provide accurate contours and existing grade measurements.
GdB record researchers contacted local municipalities to obtain filed maps, deeds and any previously filed property records. Any property mark or monumentation found within the project area was located and utilized by office staff to plot and describe property boundaries and local right-of-ways. These descriptions, including any existing easements, reservations, agreements, etc were provided to the client on a comprehensive basemap, also including the completed topographic survey and utility information.
Syracuse Airport Landside Design Study
To begin, GdB Geospatial field crews recovered and verified existing Primary Airport Control Stations (PACS) and Secondary Airport Control Stations (SACS). Once recovered, a precise survey traverse and leveling loop was completed to establish a network of three horizontal control points and two vertical benchmarks to be used in the topographic survey.
A detailed topographic and utility survey was completed for the 35 acre project site, encompassing the existing Airport Boulevard Loop Road, Arrival/Departure drop-off/pickup lanes, interior surface parking lots, parking garage, westerly terminal entrance and adjacent overflow parking low. Topographic features included existing planimetric structures, finished floor elevations, etc. GdB also included overhead site features such as pedestrian walkways and bridges, noting vertical heights, clearances and building connection points. Ground elevations and grade breaks were captures at 50’ interval to produce 1’ ground contours.
Underground utilities were mapping using a combination of provided facility records as well as extensive SUE mapping. With use of Electromagnetic Cable Locators and Ground Penetrating radar, GdB detected and designated underground utilities to Quality Level “B” standards. This included opening of any surface hardware for sanitary and storm sewers, measuring invert depths, pipe size, type and flow directions.
John B Daly Boulevard Extension
To assist with a design effort for the John B Daly Boulevard extension project in Niagara Falls, New York, GdB Geospatial was contracted by Stantec to provide Subsurface Utility Exploration (SUE) services. Project limits included portions of Niagara Street, Ferry Avenue, Walnut Avenue, and Pine Avenue intersections along the proposed extension for John Daily Blvd.
At each location, GdB Geospatial field crews detected and designated underground utilities to ASCE Quality Level “B”. To begin our efforts, GdB acquired any existing utility plans that were available based on a list of stakeholders provided by the NY811 Dig Safely New York program. Field locations of mark-out performed was located and mapped using survey grade GPS. Estimated Horizontal and Vertical positioning of utilities was given based on field collected evidence, as well as measurements gathered with Electromagnetic Cable Locators and Ground Penetrating Radar. Measurements collected utilizing these tools are described as ‘relative’ depth, not true depth.
In addition to the Utility survey, GdB provided two days of supplemental topographic survey and mapping. This included capturing elevation grade breaks at a 50’ interval, needed to map 1’ contours, locating any planimetric additions to adjacent properties, location of building footprints with elevations of a first floor and egress points, as well as existing storm sewer and sanitary structures on site (with measured pipe inverts, depths, size and type).