San Diego Hydrogeology

The National Elevation Dataset (NED) is the primary elevation data product of the USGS and serves as the elevation layer of The National Map. The NED provides basic elevation information for earth science studies and mapping applications in the United States. Scientists and resource managers use the NED data for global change research, hydrologic modeling, resource monitoring, mapping, visualization, and many other applications. The NED is updated continually to integrate newly available, improved elevation source data. All NED data are public domain.

This National Elevation Dataset has a 1/9 arc-second resolution (~3-meter cell size) and was retrieved in 15 minute blocks for the study area. The individual 15-minute blocks were merged together by region and then projected.  For this study the primary areas of interest were the San Diego Bay and the United States and Mexico border regions. Areas extending into the ocean had to be removed from the dataset used since a value of zero was used instead of a empty data option.  Our findings indicated the near shore values were not as accurate as other datasets so all values less than 2 meters NAVD88 were removed.

NOAA's National Geophysical Data Center (NGDC) is building high-resolution digital elevation models (DEMs) for select U.S. coastal regions. These integrated bathymetric-topographic DEMs are used to support tsunami forecasting and warning efforts at the NOAA Center for Tsunami Research, Pacific Marine Environmental Laboratory (PMEL). The DEMs are part of the tsunami forecast system SIFT (Short-term Inundation Forecasting for Tsunamis) currently being developed by PMEL for the NOAA Tsunami Warning Centers, and are used in the MOST (Method of Splitting Tsunami) model developed by PMEL to simulate tsunami generation, propagation, and inundation. Bathymetric, topographic, and shoreline data used in DEM compilation are obtained from various sources, including NGDC, the U.S. National Ocean Service (NOS), the U.S. Geological Survey (USGS), the U.S. Army Corps of Engineers (USACE), the Federal Emergency Management Agency (FEMA), and other federal, state, and local government agencies, academic institutions, and private companies. DEMs are referenced to the vertical tidal datum of North American Vertical Datum of 1988 (NAVD 88) or Mean High Water (MHW) and horizontal datum of World Geodetic System 1984 (WGS84). Cell size for the DEMs ranges from 1/3 arc-second (~10 meters) to 3 arc-seconds (~90 meters).

This dataset was a well refined land and ocean elevation model off shore from San Diego.  This dataset matched well with our other detailed data. The DEM borders Mexico to the south and extends north to Laguna Beach, California with a 1/3 arc-second (~10 meter) resolution. This dataset was retrieved as one complete ASCII grid which was then projected to the study datum and projection.

The National Elevation Dataset (NED) is the primary elevation data product of the USGS and serves as the elevation layer of The National Map. The NED provides basic elevation information for earth science studies and mapping applications in the United States. Scientists and resource managers use the NED data for global change research, hydrologic modeling, resource monitoring, mapping, visualization, and many other applications. The NED is updated continually to integrate newly available, improved elevation source data. All NED data are public domain.

The National Elevation Dataset 1/3 arc-second resolution was used to complete the DEM for the land-based portion of the San Diego Hydrogeology study.  This dataset extends into Mexico and utilizes the best data available as one complete and seamless DEM.  This dataset was retrieved in 1 degree blocks for the study area. The blocks were merged together and then projected in to the projection used for the study. All data less than 2 meters NAVD88 were removed in the ocean area of the dataset.

NGDC's U.S. Coastal Relief Model (CRM) provides a comprehensive view of the U.S. coastal zone integrating offshore bathymetry with land topography into a seamless representation of the coast. The CRM spans the U.S. East and West Coasts, the northern coast of the Gulf of Mexico, Puerto Rico, and Hawaii, reaching out to, and in places even beyond, the continental slope. Bathymetric and topographic data sources include: NGDC's NOS hydrographic surveys and multibeam bathymetry; the U.S. Geological Survey (USGS); and other federal government agencies and academic institutions. Bathymetric contours from the International Bathymetric Chart of the Caribbean Sea and the Gulf of Mexico project were also used. Digital elevation models (DEMs) of the Great Lakes, Southern Alaska, and high-resolution DEMs of U.S. coastal communities and territories are also available.

Dataset was used to complete the primary portion of the ocean included in the study area.  This dataset was available in 3 arc-second resolution.