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A hydrological model of the Mobile Bay watershed located in the northern Gulf of Mexico, (Alabama, USA) is presented. The modeling of hydrological processes is performed using the Hydrological Simulation Program Fortran (HSPF). The project region was divided into two sectors for simplifying the modeling task: an upland watershed (that included streams not draining directly to the Mobile Estuary), and several watersheds of selected streams that drain directly to the Mobile estuary (namely: Fish River, Magnolia River, and Chickasaw Creek). The Better Assessment Science Integrating Point & Nonpoint Sources (BASINS) GIS system was used to perform most of the geospatial operations, although ArcGis and ArcInfo were also used to complement geospatial processing that was not available in BASINS.

A grid generation tool, called the Mesh Generation and Refinement Tool (MGRT), has been developed using Qt4. Qt4 is a comprehensive C++ application framework which includes GUI and container class‐libraries and tools for cross‐platform development. MGRT is capable of using several types of algorithms for grid generation. This paper presents an application of the MGRT grid generation tool for creating an unstructured grid of Mobile Bay (Alabama, USA) that will be used for hydrodynamics modeling. The algorithm used in this particular application is the Advancing‐Front/Local‐Reconnection (AFLR) [1] [2]. This research shows results of grids created with MGRT and compares them to grids (for the same geographical container) created using other grid generation tools. The superior quality of the grids generated by MGRT is shown.

Scarcity of precipitation data is common when modeling and simulating watershed hydrology. Current availability of ground‐based radar stations provides estimations of precipitation in ways that were inexistent before. However, the delivering method for radar‐estimated precipitation (raster layers of precipitation values per unit time) is not the best in the context of hydrological modeling. Usually, hydrological models require precipitation time‐series organized according to a previous delineation of the watershed. This paper presents a methodology for generating and using NEXRAD precipitation data for hydrological simulation. NEXRAD or Nexrad (Next‐Generation Radar) is a network of 158 high‐resolution Doppler weather radars operated by the National Weather Service, an agency of the National Oceanic and Atmospheric Administration (NOAA) within the United States Department of Commerce. In this research, more than 70000 NEXRAD precipitation data files in XMRGS format and HRAP coordinates (for the period 1997–2005) were used to generate precipitation time series to be used by hydrological and hydrodynamic models for the Mobile (Alabama, USA) watershed and estuary. Results and comparison with measured data are presented.

The modeling and simulation of water resources phenomena in coastal areas is changing rapidly. Recent developments in information technology, remote sensing, and data collection technologies have changed the paradigms under which modeling is done. The particular natural and human environment that is present in coastal areas requires special modeling approaches; from conceptual models and numerical techniques up to results visualization and dissemination. This session intends to provide an up‐to‐date account of current modeling and simulation strategies undergoing throughout the world.

Calculation of land use and topographical parameters for hydrological models is usually performed using GIS software. Current approaches, however, are limited by the intensive user dependency on fixed routines, commands, sequences, etc., specific to the software been used. Therefore, current modeling approaches for geoprocessing suffer from a lack of interoperability. Algorithms that translate/summarize geographical information have been tightly designed to the needs and characteristics of specific models and GIS systems, and are not reusable. This means that each connection between a specific pairing of an environmental model and a GIS system requires a unique translation algorithm, which, in turn, requires new resources to repeatedly solve the same conceptual problem. This paper proposes the use of the Geospatial Object Library for Environmental Modeling (GEOLEM) as an alternative or complementary tool for calculating land use and topographical parameters. Although this research focuses on the calculati...