ABSTRACT
Airborne LiDAR surveys are now commonly used to characterize geomorphology and vegetation characteristics of wetland environments. This information can benefit wetland science and management through improved accuracy of ecosystem classifications and enhanced understanding of wetland hydrology and biogeochemistry. Wetlands present unique challenges associated with the analysis of LiDAR point clouds and digital elevation models (DEMs), however, and require different analytical considerations compared to applications in other environments such as urban areas, high-relief landscapes, and nonvegetated terrain. This chapter provides an overview of these considerations including the various types and applications of LiDAR ground and vegetation derivatives used for wetland environments. Published accuracy assessments for various types of wetlands are summarized and clearly demonstrate the effect of vegetation on ground surface elevation estimation with airborne LiDAR. A case study is presented in which a commonly used hydrologic derivative, computed from a LiDAR DEM, is compared to near-surface soil moisture in a northern peatland complex. The effectiveness of the topographic wetness index (TWI) as a predictor of near-surface soil moisture is shown to be very dependent on DEM resolution, hydrologic preprocessing method, and the specific TWI algorithm used. A different derivative, difference from mean elevation, is shown to explain spatial variability of point-scale surface soil moisture more reliably than the TWI.
