R&M performed the Hydaburg Dam Site Survey, including a boundary and design survey, in support of dam improvements. The dam survey required the use of several methods of data collection, including GPS RTK, conventional, high definition scanner, HydroLite hydrographic echo sounder and an Unmanned Aerial System (UAS) using aerial photos and LiDAR.
- The first task in the project was to establish a dam coordinate system that could be used for collecting dam data. R&M established the dam boundary by recovering existing BLM corners and computing the section lines based on communication with BLM representatives.
- R&M collected dam LiDAR from a height of 230′ above the dam ground. A total of 40 flight lines were flown for the project, and the average density of the LiDAR collected was 0.13′.
- The dam hydrographic survey was performed using a HydroLite single beam echo sounder with RTK horizontal positioning mounted to a raft. The data was processed using Trimble Business Center.
- The dam data collected via UAS and hydrographic echo sounder was supplemented by RTK and conventional methods. The overlap in data was used to assure the quality of the dam data and to ensure the accuracy of areas that could not be collected using aerial or hydrographic methods.
The dam quality assurance checks indicate that the overall LiDAR DTM surface meets ASPRS Positional Accuracy Standards for Digital Geospatial Data (Edition 1, Version 1.0 – November 2014). According to the standard, no more than 10% of the check points can exceed 1/2 the contour interval.
The final dam products included a report with positional accuracies and an AutoCAD version 2018 comprehensive topographic basemap of existing conditions.
The 8′ dam is at risk of failing and knocking out the City of Hydaburg’s water supply. This survey determined reservoir capacity, and replacement of the dam and refurbishment of the intake structure.
Services for this Project
