Characterization of Flood Plains Using Remotely Sensed Data Progress Report on Year 3 of Project James F. Cruise, Mohammad Al-Hamdan, and Fuad Musleh Department of Civil and Environmental Engineering University of Alabama in Huntsville Introduction The purpose of this component of the project was to determine the utility of remotely sensed data in characterizing the surface roughness characteristics of forested flood plain areas that might lie in highway corridors or be the object of highway crossings. Flood Plain Roughness Characterization Objective: To develop a methodology for determining roughness coefficients for flood plain corridors from remotely sensed data. The project includes both an experimental component and a remote sensing component. Specifically, the project seeks to: • Determine relationships between landscape parameters amenable to measurement from remotely sensed data and corresponding roughness measures through laboratory experiments • Develop landscape characterization techniques using remotely sensed data to estimate the parameters found to be relevant in the experimental analysis. Background The discharge capacity of flood plain cross sections can be expressed through the Manning equation: 2 / 1 3 / 2 49 . 1 S Ay n Q = where: Q = discharge (ft 3 /s); A = cross sectional area (ft 2 ); y = flow depth (ft); S = stream slope (ft/ft); and n = roughness coefficient. The retarding effects of the resistance to flow provided by landscape features such as trees, grass, boulders, etc. are encapsulated within the roughness coefficient, known as “Manning’s n”. This coefficient must be estimated from empirical sources for each area for which corridor crossings are to be designed. Therefore, the purpose of this project was to develop a methodology for providing guidance for the estimation of Manning n values from remotely sensed data sources.