Terrestrial Lidar and Bathymetric Data Integration and Potential Application for the Upper Mississippi River

Elevation data for terrestrial portions of the floodplain and bathymetric data currently exist for much of the Upper Mississippi River System.  The floodplain elevation data are attained using Light Detection and Ranging (LiDAR) technology.  Bathymetric data are collected by boat surveys with a depth sounder, because turbidity and depth limit the ability of LiDAR to collect bed elevation under water.  While some information needs can be met by using the individual datasets, an integrated spatial database for LiDAR and bathymetry is required in some cases.  For example, hydrodynamic models used to predict flow have until now been limited to predictions in low water conditions.  Other examples are information on near-shore habitat use by water birds, potential fish spawning habitat, and marshland vegetation use in these areas.  Using specialized Geographical Information System (GIS) software and high-speed computer processors, it is now possible to merge LiDAR and bathymetric data into a seamless GIS layer to meet these needs.  To accomplish this involves several steps including verifying LiDAR point classifications, development of a land/water boundary mask, rectifying discrepancies between shoreline boundaries as defined by the LiDAR and bathymetric data sets, and the  process of interpolating elevation from the two data sets to create the seamless layer of elevation.