THE DIGITAL MISSISSIPPI: 3-D VISUALIZATION OF CENTURY-SCALE CHANNEL EVOLUTION AND FLOOD RESPONSE USING THE GEOWALL SYSTEM

A prototype database of river channel and floodplain change through the past >100 years on the Mississippi river system is visualized using the GeoWall and GeoWall 2, a three-dimensional visualization and ultra-high-resolution display system. The database consists of systematic surveys, maps, hydrologic data, and major engineering modifications of the Mississippi and Missouri river system over time, at present focusing on the Middle Mississippi. Input sources were digitized, registered, rectified, standardized to a uniform vertical datum, and stored in a GIS. The full database is envisioned as a system-wide tool for statistical hydrology, hydraulic modeling, environmental assessment, and public outreach.

Visualizations were produced using software that can display over 100 million elevation datapoints interactively. The GeoWall is a three-dimensional visualization system, and the GeoWall 2 is a 8-100 million pixel ultra-high resolution display. All software is either open-sourced or from low-cost commercial vendors; further information is available at www.geowall.org.

One application of this system is to illustrate the impacts of channel regulation and levee construction on flood levels, frequencies, and floodplain zonation. As previously reported, channel and floodplain modifications along the Middle Mississippi River have resulted in increased flood hazard. Three-dimensional, interactive visualization using GeoWall illustrates evolving flood response of the Mississippi for four time-slices: 1880, 1908, 1940, and 1998. This pairing of geo-/hydro-informatic database and advanced visualization capability creates a powerful tool for fluvio-geomorphic research, educational applications, and conveying changes in river and flood dynamics to both expert and non-scientific audiences.