MONITORING GEOMORPHOLOGICAL CHANGE ON GALVESTON ISLAND USING AIRBORNE AND TERRESTRIAL LIDAR

Galveston Island resides in one of the largest metropolises in the world. Major geological processes affecting the island morphology are coastal erosion, accretion, and redistribution of sediments. The Galveston sea wall has protected the city from coastal erosion; however, at many other places, the ocean has penetrated the island by more than 100 meters since 1900. The major driving forces include wave climate and storm activity. Changes to the barrier island system occur on multiple time scales ranging from days (hurricanes) to centuries (tectonics, climate change).

In order to monitor spatio-temporal change over multiple time scales, the island morphology was monitored through GNSS, airborne and terrestrial LiDAR over the last 12 years. In total, three airborne campaigns (2001, 2006, 2010) and two terrestrial campaigns (at San Luis Pass and Jamaica Beach; 2010, 2013) have been conducted.

Initial results show sediment accretion at San Luis Pass and erosion at Jamaica Beach as well as most of the southern shoreline. We will present results from all five campaigns as well as uncertainty estimates obtained from cross-calibration between airborne, terrestrial and GNSS observations. Ultimately, the objective is to separate short-term and long-term processes and to quantify their impact on the geomorphology of Galveston Island. This allows for constraining future predictions of shoreline migration and to assist in planning of mitigation strategies.