Handheld LiDAR Mapping: SLAM dunk for Fluvial Geomorphology?
Brian O’Neill
Burns & McDonnell
Chicago, IL
Authors: O’Neill, Brian. J., Patrick Vrablik, and Nathan Kilgore. 2023
The measurement of stream dimension, pattern, and profile is fundamental to fluvial geomorphic assessment and monitoring. Advances in measurement tools and technology have enabled fluvial geomorphologists the capability to rapidly collect extensive, high-resolution, and accurate datasets. While these advanced technologies such as LiDAR are becoming more accessible, practitioners must weigh the advantages versus the drawbacks over more traditional tools such as direct leveling and even geodetic surveys. This presentation will describe the application of a handheld, survey-grade LiDAR mapping tool to capture geomorphic features of several thousand feet of ephemeral, intermittent, and perennial streams in support of a natural channel assessment and design project in the Bluegrass Region of Kentucky. The handheld LiDAR was equipped with simultaneous localization and mapping (SLAM) technology and true colorization of the point cloud. Ground control was achieved using smart control points and a survey-grade rover. Coincident direct leveling, Global Navigation Satellite System (GNSS) surveying, and aerial LiDAR survey data were also collected within the study area.
The handheld LiDAR was employed for its ability to collect high-resolution, shadowless data over a relatively short period of time under challenging conditions. The study site includes an array of entrenched stream channels, many with a dense canopy and brush cover and complex anastomosed stream segments. In-situ evaluations of the handheld LiDAR tool included its ability to provide channel bed roughness at representative riffle cross sections and depositional features, capture accurate elevation data within clear shallow water features, and the ability to support ad-hoc measurements for stream quality and stability indices. This presentation will describe the technology and survey implementation procedures, the advantages and disadvantages of the handheld LiDAR technology relative to the other methods, challenges and lessons learned, and recommendations for use of handheld LiDAR for fluvial geomorphologists.
About Brian O’Neill
Mr. O’Neill is an aquatic ecologist, serving the environmental planning and permitting needs of utilities, transportation, private/commercial developers, and municipalities throughout the country. Primary areas of expertise include ecological assessments, hydrographic studies, aquatic and terrestrial habitat restoration, and local, state and federal permitting for Clean Water Act §404,401, and §316 (a)(b); Endangered Species Act §7 consultations; and NEPA.
Mr. O’Neill applies natural channel design principles and bioengineering methodologies to stream and wetland restoration projects. Specialties include balancing restoration goals with utility and infrastructure assets in the built environment.
