MORPHOLOGICAL MONITORING OF A STORM-DOMINATED MICROTIDAL BARRIER ISLAND: GALVESTON ISLAND’S WESTEND, TEXAS, USA

This pilot project is an ongoing monitoring program which quantifies the relationships between temporal and spatial scales of morphologic change on a heavily developed and modified transgressive barrier island. This project incorporates not only traditional cross-shore profiling techniques, but also establishes an along-shore spatial monitoring technique to determine shoreline migration. This involves tracing the wet line immediately after the high tide utilizing a post-processed kinematic GPS mounted on an all terrain vehicle. Weekly monitoring enables determination of shoreline migration and deviation due to storm events, seasonal, and annual cycles. Archiving and analyses of these short-term changes provides a long time-series of shoreline position which will be used to project future coastal change.

Preliminary results indicate that in response to astronomical tidal cycles and non-storm wave energies there is a net sediment migration from the northeast to the southwest. In October, 2004 the Upper Texas Coast experienced a peripheral high energy event due to Hurricane Ivan. Consequently, the existing nourished templates were heavily scoured and introduced into the littoral system resulting in significant accretion at the extreme west end of the island.

Incorporation of this monitoring project with existing data will enable the opportunity of scientifically based sound management for the complex task of local and state coastal planning and decision making.