Remote Sensing Technologies Case Study

Inaccessible Environmental Remediation Survey Performed with Remote Sensing Technologies

Arcadis of New York, Inc. (Arcadis) retained Thew Associates PE-LS, PLLC (Thew) to perform surveying services to support engineering design for an environmental remediation at a former industrial site located along a major river in Upstate, New York.

The former industrial site is comprised of a former hydroelectric powerhouse and associated infrastructure that are abandoned and dilapidated and abut the easterly shoreline of the river, which is a steep vertical cliff and constitute a health and safety risk.

In support of engineering design, Arcadis required topographic and boundary retracement surveying and mapping of an approximate 9-acre property, and bathymetric surveying and mapping within the river adjacent to the former powerhouse. Due to challenging site conditions including inaccessible terrain and health and safety risks to survey technicians, Thew staff utilized multiple technologies to collect the geospatial information required by Arcadis. An Unmanned Aerial Vehicle (UAV) equipped with a Riegl miniVUX-1 LiDAR sensor integrated with an RGB camera was utilized to acquire LiDAR data and colored aerial photography (RGB) to accomplish the topographic and planimetric data collection, while conventional surveying techniques were utilized to locate physical boundary evidence and surficial evidence of subsurface utilities beyond the high-risk areas. Thew staff also collected videography along the easterly shoreline of the major river to capture detail of the site features utilizing a UAV.

The LiDAR data was utilized to create a seamless digital elevation model (DEM) which provided one-foot contours of the site, while the aerial photography was utilized to map the planimetrics and provide high quality images of the abandoned and dilapidated structures in inaccessible areas. The videography was reviewed multiple times and utilized to show many site features not discernable through the LiDAR and aerial photography. The LiDAR data and aerial photography were also utilized to assist in determining the westerly boundary line of the property. The westerly boundary line was intended to follow the westerly edge of a former structure which was discernable in the LiDAR data and aerial photography.

The acoustic bathymetric data was collected utilizing a Norbit iWBMS multi-beam echo sounder (MBES) coupled with an Applanix POS MV Wave master navigation system, and Hypack hydrographic surveying software mounted on a 15-foot jon boat. “Thew provided an excellent site survey, using a variety of survey methods, to document complex site conditions for this challenging site – steep banks, large/complex structures and feature, river bathymetry, etc. Thew’s field crew completed the survey work in a timely manner, while adhering to the client’s strict Covid-19 protocols. The survey deliverables, including a site base map, photos, and videos, were a tremendous aid to the design team, to help 1) understand current site conditions and 2) allowing for the review of site conditions/features following the completion of the field work”. – Jason Golubski, P.E., Project Manager, Arcadis

“To fulfill Arcadis’ surveying and mapping requirements, our staff was required to utilize a multitude of the remote sensing tools in our repertoire to safely and efficiently capture the required spatial data. It was a great opportunity to integrate multi-beam sonar, low altitude LiDAR, and digital aerial imagery to solve the geospatial challenges this site posed. I was really impressed with the accuracy and quality of the data, the manner that our staff extracted the data, and the final mapping deliverable to the client. We would not have been able to safely perform this survey without the use of remote sensing technologies. I am amazed at how rapidly technological advances have changed the manner that Land Surveyors collect spatial information. It is an exciting time for our profession.” – James Thew, PLS, Principal, Thew Associates


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