TM-006: NEON AOP Surveys of City of Boulder Pre and Post 2013 Flood Event

Publication Type:
Report
Source:
NEON Technical Memorandum Series, NEON, Number 006, Boulder (2015)
Abstract

The National Ecological Observatory Network (NEON) operates an airborne remote sensing payload which contains a LiDAR (Light Detection and Ranging) sensor (Kampe et al., 2010). LiDAR provides a highly accurate and dense sampling of the earth’s surface, enabling a detailed mapping of the land surface topography. Two months prior to a major flood event in Colorado, which occurred in September of 2013, NEON undertook a LIDAR survey of the city of Boulder. Following the flood event, a second LiDAR acquisition was undertaken. A high resolution digital topographic map of the ground surface, termed a DTM (Digital Terrain Model), was produced for each survey at 1 m resolution. The DTMs were subtracted to produce a DTM of difference (DOD) map of the vertical topographic change caused by the flood event. An error analysis of the resulting DTMs generally indicates that changes observed above ±0.1 m are likely due to physical processes related to the flood, while changes below this threshold can be attributed to sensor and processing uncertainty. Resulting topographic changes due to overland flow were detectable in some stream headwater locations, while topographic changes within stream channels were prevalent. Some stream channels exhibited substantial degradation, especially in high slope regions as channels descended through mountainous regions of the landscape. Stream channels also experienced substantial degradation (> 3 m) as the channels transitioned from high to low slopes. Areas of substantial channel deposition were noted within the urban boundary of the City of Boulder. The LIDAR data described in this document is available for public retrieval through request to NEON.

NEON_Technical_Memo_006a_BLDR Flood_Pre_Post_Assessment.pdfairborne remote sensingairborne data