A few smoke plumes are visible in this image of the Southeastern United States from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS)
Image courtesy SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

Since the year 2000, eastern Louisiana, coastal Mississippi, Alabama, and the western Florida panhandle have been affected by 28 tropical storms, seven of which were hurricanes. These tropical cyclones have significantly altered normal coastal processes and characteristics in the Gulf region through sediment disturbance. In fact, tropical storm-induced sediment disturbance is a factor in four of the five GOMA priority issues: water quality for beaches and shellfish beds, wetland and coastal conservation restoration, characterization of Gulf habitats, and reduction of nutrient inputs to coastal systems. During tropical storms water quality is affected throughout the Gulf and its estuaries when turbidity increases from substrate disturbance and increased fluvial input carrying both natural and anthropogenic particulates and chemicals. Wetlands and coastal habitats are affected by tropical storm activity with sediment being eroded and deposited, thus altering the shoreline and disturbing natural habitats. Coastal and marine habitats are greatly influenced by increased tropical storm-induced wave energy with substrate disturbance and increased sediment from streams and rivers contributing to increased suspended load. Nutrient input is also affected by tropical storms as storm-water runoff in particular can carry a high level of agricultural and industrial sediment and chemicals.

The importance of sediments upon water quality, coastal erosion, habitats and nutrients has made their study and monitoring vital to decision makers in the region. Currently agencies such as the United States Army Corps of Engineers, NASA, and the Geological Survey of Alabama (GSA) are employing a variety of in-situ and airborne-based measurements to assess and monitor sediment loading and deposition (GSA 2008). These methods provide highly accurate information but are limited in geographic range, are not continuous over a region and, in the case of airborne LIDAR are expensive and do not recur on a regular basis. But the general usage of satellite based data products by decision makers in the Gulf of Mexico and other coastal locations with respect to tropical storm activity remains limited.

Decision support products derived from MODIS, SeaWiFS and Landsat data that show suspended sediments can provide valuable information related to wetlands management, coastal habitat restoration, marine ecology, coastal geomorphology, conservation, and other coastal activities. As shown by the letters of support in section 9, this project will provide a much needed resource for end users in the region. The products will be used for improved measurements of water quality (Cebrian), assessment of sedimentation during storm events and its impact on critical coastal habitats (Ferraro), assessment of sedimentation versus sea level rise in natural marshes (Roach) and for better understanding of the impact of sediment and sediment deposits on water quality, living resources, and habitats of the estuarine environment (Swann).

The proposed Sediment Analysis Network for Decision Support (SANDS) project will help resolve the GOMA priority issues by obtaining NASA MODIS, Landsat, and SeaWiFS data for multiple tropical storms and hurricanes over a number of years, and enhancing the data to generate decision support products highlighting suspended sediment and storm surge sediment deposits. SANDS will make the enhanced suspended sediment imagery readily available to north central Gulf of Mexico end users through an online system, in a format they can easily use, and provide them a path to the original NASA data. Many groups involved in coastal management, conservation, planning, recovery, and mitigation will greatly benefit from the information these satellite data will provide. By making multi-spectral satellite products available for multiple common storm events, SANDS will provide end users the opportunity to better analyze, detect, and identify compositions and patterns of suspended sediment and sediment deposits.