Jan 26, 2011
The Coastal Lidar and Radar Imaging System, CLARIS, is a fully-mobile mapping system that is designed to operate during storms, collecting topography data of the beach from a terrestrial laser scanner as well as bathymetry and wave data in the surf-zone from radar-derived wave celerity measurements. In the past, mapping systems were not capable of quantitatively measuring both subaerial topography and shallow-water bathymetry of coastal regions during storms. As a result, researchers have lacked the needed quantitative data to improve and assess predictive models of coastal change and damage from storms when much of the change occurs. Utilizing a tracked vehicle and full integration of a scanning terrestrial laser with a radar imaging system, CLARIS can survey 10-km of coastline in 2 hours and provide bathymetry from 2-m water depth to 1km offshore to within 10% accuracy as well as topography of the beach and dune to within 10 cm. Surf-zone morphology metrics, such as the position of shore-parallel bars are also objectively extracted from time-averaged radar mosaics. CLARIS has showed its value through acquisition of an unprecedented data set that captured evolving surf zone dynamics during Hurricane Earl in September 2010. CLARIS data are currently being used to improve state of the art predictions of coastal inundation and vulnerability during storms, as well as measure previously undocumented spatial and temporal variability in sub-aerial beach volume change throughout the course of a storm. Moreover, CLARIS may prove to be an important component to Force Projection operations by providing real-time, remotely sensed information concerning surf zone conditions (littoral penetration points) and preferred locations for staging infrastructure on the beach.
Prior to CLARIS, collecting simultaneous observations of oceanographic conditions and vulnerable coastal landforms over large areas and during storms has been virtually impossible. The coastal research community has long recognized the value of ‘during storm’ data because most of the relevant processes (e.g. sediment transport, overwash, shoreline change, infrastructure damage) occur during these energetic events. Unfortunately, collecting observations where the signal is strongest necessitates working in the surf zone and over inundated land, one of the most challenging environments on earth. The forces of large breaking waves are tremendous, the depths are too shallow for vessel operation, and the scales of change are so large that measurements from just a few locations (i.e. collected from bomb-proof, in-situ instrument mounts) are woefully inadequate to characterize the complexity of the processes.
CLARIS represents a significant step forward in coastal observing techniques, providing high-resolution (sub-meter) measurements of low-lying lands, depths across shallow-water regions, and wave parameters (e.g. direction, wavelength, period), all during storm conditions and over large areas. CLARIS has already yielded scientific breakthroughs in understanding 1) shoreline erosional hotspots, 2) beach overwash, and 3) sediment exchange between the beach and nearshore shoals. Besides collecting an unprecedented data set that captured evolving surf zone dynamics during Hurricane Earl in September 2010, CLARIS was utilized to assess response of a beach re-nourishment project at Benson Beach, Washington, work done in support of the USACE Portland District. Also, as part of collaborative research with the USGS, CLARIS was applied to observe and measure sediment exchange between shoals and the beach system at Cape Hatteras, NC. In addition, CLARIS is receiving R&D funding support from ONR and other DoD sources and being utilized to improve Force Projection operations over ever-changing, shallow-water regions.
POCs: Jesse E. McNinch, PhD, Jesse.E.McNinch@usace.army.mil and Kate L. Brodie, PhD, Kate.L.Brodie@usace.army.mil.